diff --git a/.cargo/config.toml b/.cargo/config.toml
index 0bab205cd..72f445d8a 100644
--- a/.cargo/config.toml
+++ b/.cargo/config.toml
@@ -1,7 +1,9 @@
 [alias]
-chk = "hack check --workspace --all-features --tests --examples"
-lint = "hack --clean-per-run clippy --workspace --tests --examples"
+chk = "check --workspace --all-features --tests --examples --bins"
+lint = "clippy --workspace --tests --examples"
 ci-min = "hack check --workspace --no-default-features"
 ci-min-test = "hack check --workspace --no-default-features --tests --examples"
-ci-default = "hack check --workspace"
-ci-full = "check --workspace --bins --examples --tests"
+ci-default = "check --workspace --bins --tests --examples"
+ci-full = "check --workspace --all-features --bins --tests --examples"
+ci-test = "test --workspace --all-features --lib --tests --no-fail-fast -- --nocapture"
+ci-doctest = "hack test --workspace --all-features --doc --no-fail-fast -- --nocapture"
diff --git a/.github/ISSUE_TEMPLATE/config.yml b/.github/ISSUE_TEMPLATE/config.yml
index d8c6d66ca..bfa124ffd 100644
--- a/.github/ISSUE_TEMPLATE/config.yml
+++ b/.github/ISSUE_TEMPLATE/config.yml
@@ -1,15 +1,8 @@
 blank_issues_enabled: true
 contact_links:
-  - name: GitHub Discussions
-    url: https://github.com/actix/actix-web/discussions
-    about: Actix Web Q&A
-  - name: Gitter chat (actix-web)
-    url: https://gitter.im/actix/actix-web
-    about: Actix Web Q&A
-  - name: Gitter chat (actix)
-    url: https://gitter.im/actix/actix
-    about: Actix (actor framework) Q&A
   - name: Actix Discord
     url: https://discord.gg/NWpN5mmg3x
     about: Actix developer discussion and community chat
-
+  - name: GitHub Discussions
+    url: https://github.com/actix/actix-web/discussions
+    about: Actix Web Q&A
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 585b3f497..22b92759a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -44,13 +44,6 @@ jobs:
           profile: minimal
           override: true
 
-      - name: Install ${{ matrix.version }}
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: ${{ matrix.version }}-${{ matrix.target.triple }}
-          profile: minimal
-          override: true
-
       - name: Generate Cargo.lock
         uses: actions-rs/cargo@v1
         with:
@@ -66,43 +59,33 @@ jobs:
 
       - name: check minimal
         uses: actions-rs/cargo@v1
-        with:
-          command: hack
-          args: check --workspace --no-default-features
+        with: { command: ci-min }
 
       - name: check minimal + tests
         uses: actions-rs/cargo@v1
-        with:
-          command: hack
-          args: check --workspace --no-default-features --tests --examples
+        with: { command: ci-min-test }
 
+      - name: check default
+        uses: actions-rs/cargo@v1
+        with: { command: ci-default }
+      
       - name: check full
         uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --workspace --bins --examples --tests
+        with: { command: ci-full }
 
       - name: tests
-        uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --workspace --all-features --no-fail-fast -- --nocapture
-            --skip=test_h2_content_length
-            --skip=test_reading_deflate_encoding_large_random_rustls
-
-      - name: tests (actix-http)
         uses: actions-rs/cargo@v1
         timeout-minutes: 40
         with:
-          command: test
-          args: --package=actix-http --no-default-features --features=rustls -- --nocapture
+          command: ci-test
+          args: --skip=test_reading_deflate_encoding_large_random_rustls
 
-      - name: tests (awc)
+      - name: doc tests
+        # due to unknown issue with running doc tests on macOS
+        if: matrix.target.os == 'ubuntu-latest'
         uses: actions-rs/cargo@v1
         timeout-minutes: 40
-        with:
-          command: test
-          args: --package=awc --no-default-features --features=rustls -- --nocapture
+        with: { command: ci-doctest }
 
       - name: Generate coverage file
         if: >
@@ -123,5 +106,5 @@ jobs:
 
       - name: Clear the cargo caches
         run: |
-          cargo install cargo-cache --no-default-features --features ci-autoclean
+          cargo install cargo-cache --version 0.6.2 --no-default-features --features ci-autoclean
           cargo-cache
diff --git a/.github/workflows/clippy-fmt.yml b/.github/workflows/clippy-fmt.yml
index e966fa4ab..957256d32 100644
--- a/.github/workflows/clippy-fmt.yml
+++ b/.github/workflows/clippy-fmt.yml
@@ -36,4 +36,4 @@ jobs:
         uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          args: --workspace --tests --all-features
+          args: --workspace --all-features --tests
diff --git a/.gitignore b/.gitignore
index 638a4397a..543403267 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,3 +16,6 @@ guide/build/
 
 # Configuration directory generated by CLion
 .idea
+
+# Configuration directory generated by VSCode
+.vscode
diff --git a/CHANGES.md b/CHANGES.md
index 4b3f1d7ab..fb3bc56ce 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,23 +1,60 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+### Removed
+* `FromRequest::Config` was removed. [#2233]
+
+[#2233]: https://github.com/actix/actix-web/pull/2233
+
+
+## 4.0.0-beta.8 - 2021-06-26
+### Added
+* Add `ServiceRequest::parts_mut`. [#2177]
+* Add extractors for `Uri` and `Method`. [#2263]
+* Add extractors for `ConnectionInfo` and `PeerAddr`. [#2263]
+* Add `Route::service` for using hand-written services as handlers. [#2262]
+
+### Changed
+* Change compression algorithm features flags. [#2250]
+* Deprecate `App::data` and `App::data_factory`. [#2271]
+* Smarter extraction of `ConnectionInfo` parts. [#2282]
+
+### Fixed
+* Scope and Resource middleware can access data items set on their own layer. [#2288]
+
+[#2177]: https://github.com/actix/actix-web/pull/2177
+[#2250]: https://github.com/actix/actix-web/pull/2250
+[#2271]: https://github.com/actix/actix-web/pull/2271
+[#2262]: https://github.com/actix/actix-web/pull/2262
+[#2263]: https://github.com/actix/actix-web/pull/2263
+[#2282]: https://github.com/actix/actix-web/pull/2282
+[#2288]: https://github.com/actix/actix-web/pull/2288
+
+
+## 4.0.0-beta.7 - 2021-06-17
 ### Added
 * `HttpServer::worker_max_blocking_threads` for setting block thread pool. [#2200]
 
 ### Changed
+* Adjusted default JSON payload limit to 2MB (from 32kb) and included size and limits in the `JsonPayloadError::Overflow` error variant. [#2162]
+[#2162]: (https://github.com/actix/actix-web/pull/2162)
 * `ServiceResponse::error_response` now uses body type of `Body`. [#2201]
 * `ServiceResponse::checked_expr` now returns a `Result`. [#2201]
 * Update `language-tags` to `0.3`.
 * `ServiceResponse::take_body`. [#2201]
 * `ServiceResponse::map_body` closure receives and returns `B` instead of `ResponseBody<B>` types. [#2201]
+* All error trait bounds in server service builders have changed from `Into<Error>` to `Into<Response<AnyBody>>`. [#2253]
+* All error trait bounds in message body and stream impls changed from `Into<Error>` to `Into<Box<dyn std::error::Error>>`. [#2253]
+* `HttpServer::{listen_rustls(), bind_rustls()}` now honor the ALPN protocols in the configuation parameter. [#2226]
+* `middleware::normalize` now will not try to normalize URIs with no valid path [#2246]
 
 ### Removed
 * `HttpResponse::take_body` and old `HttpResponse::into_body` method that casted body type. [#2201]
-* `FromRequest::Config` was removed. [#2233]
 
 [#2200]: https://github.com/actix/actix-web/pull/2200
 [#2201]: https://github.com/actix/actix-web/pull/2201
-[#2233]: https://github.com/actix/actix-web/pull/2233
+[#2253]: https://github.com/actix/actix-web/pull/2253
+[#2246]: https://github.com/actix/actix-web/pull/2246
 
 
 ## 4.0.0-beta.6 - 2021-04-17
diff --git a/Cargo.toml b/Cargo.toml
index 91d1212fc..9d4e9562f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web"
-version = "4.0.0-beta.6"
+version = "4.0.0-beta.8"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Actix Web is a powerful, pragmatic, and extremely fast web framework for Rust"
 keywords = ["actix", "http", "web", "framework", "async"]
@@ -17,7 +17,7 @@ edition = "2018"
 
 [package.metadata.docs.rs]
 # features that docs.rs will build with
-features = ["openssl", "rustls", "compress", "cookies", "secure-cookies"]
+features = ["openssl", "rustls", "compress-brotli", "compress-gzip", "compress-zstd", "cookies", "secure-cookies"]
 rustdoc-args = ["--cfg", "docsrs"]
 
 [lib]
@@ -40,10 +40,14 @@ members = [
 # resolver = "2"
 
 [features]
-default = ["compress", "cookies"]
+default = ["compress-brotli", "compress-gzip", "compress-zstd", "cookies"]
 
-# content-encoding support
-compress = ["actix-http/compress"]
+# Brotli algorithm content-encoding support
+compress-brotli = ["actix-http/compress-brotli", "__compress"]
+# Gzip and deflate algorithms content-encoding support
+compress-gzip = ["actix-http/compress-gzip", "__compress"]
+# Zstd algorithm content-encoding support
+compress-zstd = ["actix-http/compress-zstd", "__compress"]
 
 # support for cookies
 cookies = ["cookie"]
@@ -57,9 +61,13 @@ openssl = ["actix-http/openssl", "actix-tls/accept", "actix-tls/openssl"]
 # rustls
 rustls = ["actix-http/rustls", "actix-tls/accept", "actix-tls/rustls"]
 
+# Internal (PRIVATE!) features used to aid testing and cheking feature status.
+# Don't rely on these whatsoever. They may disappear at anytime.
+__compress = []
+
 [dependencies]
 actix-codec = "0.4.0"
-actix-macros = "0.2.0"
+actix-macros = "0.2.1"
 actix-router = "0.2.7"
 actix-rt = "2.2"
 actix-server = "2.0.0-beta.3"
@@ -68,10 +76,11 @@ actix-utils = "3.0.0"
 actix-tls = { version = "3.0.0-beta.5", default-features = false, optional = true }
 
 actix-web-codegen = "0.5.0-beta.2"
-actix-http = "3.0.0-beta.6"
+actix-http = "3.0.0-beta.8"
 
 ahash = "0.7"
 bytes = "1"
+cfg-if = "1"
 cookie = { version = "0.15", features = ["percent-encode"], optional = true }
 derive_more = "0.99.5"
 either = "1.5.3"
@@ -95,16 +104,16 @@ time = { version = "0.2.23", default-features = false, features = ["std"] }
 url = "2.1"
 
 [dev-dependencies]
-actix-test = { version = "0.1.0-beta.2", features = ["openssl", "rustls"] }
-awc = { version = "3.0.0-beta.5", features = ["openssl"] }
+actix-test = { version = "0.1.0-beta.3", features = ["openssl", "rustls"] }
+awc = { version = "3.0.0-beta.7", features = ["openssl"] }
 
 brotli2 = "0.3.2"
-criterion = "0.3"
+criterion = { version = "0.3", features = ["html_reports"] }
 env_logger = "0.8"
 flate2 = "1.0.13"
+zstd = "0.7"
 rand = "0.8"
 rcgen = "0.8"
-serde_derive = "1.0"
 tls-openssl = { package = "openssl", version = "0.10.9" }
 tls-rustls = { package = "rustls", version = "0.19.0" }
 
@@ -126,15 +135,15 @@ awc = { path = "awc" }
 
 [[test]]
 name = "test_server"
-required-features = ["compress", "cookies"]
+required-features = ["compress-brotli", "compress-gzip", "compress-zstd", "cookies"]
 
 [[example]]
 name = "basic"
-required-features = ["compress"]
+required-features = ["compress-gzip"]
 
 [[example]]
 name = "uds"
-required-features = ["compress"]
+required-features = ["compress-gzip"]
 
 [[example]]
 name = "on_connect"
diff --git a/MIGRATION.md b/MIGRATION.md
index c5d08e8c1..c644d95e9 100644
--- a/MIGRATION.md
+++ b/MIGRATION.md
@@ -12,6 +12,19 @@
 
 * The `type Config` of `FromRequest` was removed.
 
+* Feature flag `compress` has been split into its supported algorithm (brotli, gzip, zstd).
+  By default all compression algorithms are enabled.
+  To select algorithm you want to include with `middleware::Compress` use following flags:
+  - `compress-brotli`
+  - `compress-gzip`
+  - `compress-zstd`
+  If you have set in your `Cargo.toml` dedicated `actix-web` features and you still want
+  to have compression enabled. Please change features selection like bellow:
+
+  Before: `"compress"`
+  After: `"compress-brotli", "compress-gzip", "compress-zstd"`
+
+
 ## 3.0.0
 
 * The return type for `ServiceRequest::app_data::<T>()` was changed from returning a `Data<T>` to
diff --git a/README.md b/README.md
index 60ec57c60..309a18466 100644
--- a/README.md
+++ b/README.md
@@ -6,10 +6,10 @@
   <p>
 
 [![crates.io](https://img.shields.io/crates/v/actix-web?label=latest)](https://crates.io/crates/actix-web)
-[![Documentation](https://docs.rs/actix-web/badge.svg?version=4.0.0-beta.5)](https://docs.rs/actix-web/4.0.0-beta.5)
+[![Documentation](https://docs.rs/actix-web/badge.svg?version=4.0.0-beta.8)](https://docs.rs/actix-web/4.0.0-beta.8)
 [![Version](https://img.shields.io/badge/rustc-1.46+-ab6000.svg)](https://blog.rust-lang.org/2020/03/12/Rust-1.46.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-web.svg)
-[![Dependency Status](https://deps.rs/crate/actix-web/4.0.0-beta.5/status.svg)](https://deps.rs/crate/actix-web/4.0.0-beta.5)
+[![Dependency Status](https://deps.rs/crate/actix-web/4.0.0-beta.8/status.svg)](https://deps.rs/crate/actix-web/4.0.0-beta.8)
 <br />
 [![build status](https://github.com/actix/actix-web/workflows/CI%20%28Linux%29/badge.svg?branch=master&event=push)](https://github.com/actix/actix-web/actions)
 [![codecov](https://codecov.io/gh/actix/actix-web/branch/master/graph/badge.svg)](https://codecov.io/gh/actix/actix-web) 
@@ -25,7 +25,7 @@
 * Streaming and pipelining
 * Keep-alive and slow requests handling
 * Client/server [WebSockets](https://actix.rs/docs/websockets/) support
-* Transparent content compression/decompression (br, gzip, deflate)
+* Transparent content compression/decompression (br, gzip, deflate, zstd)
 * Powerful [request routing](https://actix.rs/docs/url-dispatch/)
 * Multipart streams
 * Static assets
diff --git a/actix-files/CHANGES.md b/actix-files/CHANGES.md
index 12b70c135..db047c44c 100644
--- a/actix-files/CHANGES.md
+++ b/actix-files/CHANGES.md
@@ -1,22 +1,34 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+
+
+## 0.6.0-beta.6 - 2021-06-26
+* Added `Files::path_filter()`. [#2274]
+* `Files::show_files_listing()` can now be used with `Files::index_file()` to show files listing as a fallback when the index file is not found. [#2228]
+
+[#2274]: https://github.com/actix/actix-web/pull/2274
+[#2228]: https://github.com/actix/actix-web/pull/2228
+
+
+## 0.6.0-beta.5 - 2021-06-17
 * `NamedFile` now implements `ServiceFactory` and `HttpServiceFactory` making it much more useful in routing. For example, it can be used directly as a default service. [#2135]
 * For symbolic links, `Content-Disposition` header no longer shows the filename of the original file. [#2156]
 * `Files::redirect_to_slash_directory()` now works as expected when used with `Files::show_files_listing()`. [#2225]
+* `application/{javascript, json, wasm}` mime type now have `inline` disposition by default. [#2257]
 
 [#2135]: https://github.com/actix/actix-web/pull/2135
 [#2156]: https://github.com/actix/actix-web/pull/2156
 [#2225]: https://github.com/actix/actix-web/pull/2225
+[#2257]: https://github.com/actix/actix-web/pull/2257
 
 
 ## 0.6.0-beta.4 - 2021-04-02
-* No notable changes.
-
 * Add support for `.guard` in `Files` to selectively filter `Files` services. [#2046]
 
 [#2046]: https://github.com/actix/actix-web/pull/2046
 
+
 ## 0.6.0-beta.3 - 2021-03-09
 * No notable changes.
 
diff --git a/actix-files/Cargo.toml b/actix-files/Cargo.toml
index b97badd3e..ef288215b 100644
--- a/actix-files/Cargo.toml
+++ b/actix-files/Cargo.toml
@@ -1,13 +1,11 @@
 [package]
 name = "actix-files"
-version = "0.6.0-beta.4"
+version = "0.6.0-beta.6"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Static file serving for Actix Web"
-readme = "README.md"
 keywords = ["actix", "http", "async", "futures"]
 homepage = "https://actix.rs"
-repository = "https://github.com/actix/actix-web.git"
-documentation = "https://docs.rs/actix-files/"
+repository = "https://github.com/actix/actix-web"
 categories = ["asynchronous", "web-programming::http-server"]
 license = "MIT OR Apache-2.0"
 edition = "2018"
@@ -17,7 +15,8 @@ name = "actix_files"
 path = "src/lib.rs"
 
 [dependencies]
-actix-web = { version = "4.0.0-beta.6", default-features = false }
+actix-web = { version = "4.0.0-beta.8", default-features = false }
+actix-http = "3.0.0-beta.8"
 actix-service = "2.0.0"
 actix-utils = "3.0.0"
 
@@ -34,5 +33,5 @@ percent-encoding = "2.1"
 
 [dev-dependencies]
 actix-rt = "2.2"
-actix-web = "4.0.0-beta.6"
-actix-test = "0.1.0-beta.2"
+actix-web = "4.0.0-beta.8"
+actix-test = "0.1.0-beta.3"
diff --git a/actix-files/README.md b/actix-files/README.md
index 895d5e687..13c301c56 100644
--- a/actix-files/README.md
+++ b/actix-files/README.md
@@ -3,17 +3,16 @@
 > Static file serving for Actix Web
 
 [![crates.io](https://img.shields.io/crates/v/actix-files?label=latest)](https://crates.io/crates/actix-files)
-[![Documentation](https://docs.rs/actix-files/badge.svg?version=0.6.0-beta.4)](https://docs.rs/actix-files/0.6.0-beta.4)
+[![Documentation](https://docs.rs/actix-files/badge.svg?version=0.6.0-beta.6)](https://docs.rs/actix-files/0.6.0-beta.6)
 [![Version](https://img.shields.io/badge/rustc-1.46+-ab6000.svg)](https://blog.rust-lang.org/2020/03/12/Rust-1.46.html)
 ![License](https://img.shields.io/crates/l/actix-files.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-files/0.6.0-beta.4/status.svg)](https://deps.rs/crate/actix-files/0.6.0-beta.4)
+[![dependency status](https://deps.rs/crate/actix-files/0.6.0-beta.6/status.svg)](https://deps.rs/crate/actix-files/0.6.0-beta.6)
 [![Download](https://img.shields.io/crates/d/actix-files.svg)](https://crates.io/crates/actix-files)
-[![Join the chat at https://gitter.im/actix/actix](https://badges.gitter.im/actix/actix.svg)](https://gitter.im/actix/actix?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
 ## Documentation & Resources
 
 - [API Documentation](https://docs.rs/actix-files/)
 - [Example Project](https://github.com/actix/examples/tree/master/basics/static_index)
-- [Chat on Gitter](https://gitter.im/actix/actix-web)
 - Minimum supported Rust version: 1.46 or later
diff --git a/actix-files/src/files.rs b/actix-files/src/files.rs
index fc8fd2531..49d81eb03 100644
--- a/actix-files/src/files.rs
+++ b/actix-files/src/files.rs
@@ -1,9 +1,17 @@
-use std::{cell::RefCell, fmt, io, path::PathBuf, rc::Rc};
+use std::{
+    cell::RefCell,
+    fmt, io,
+    path::{Path, PathBuf},
+    rc::Rc,
+};
 
 use actix_service::{boxed, IntoServiceFactory, ServiceFactory, ServiceFactoryExt};
 use actix_utils::future::ok;
 use actix_web::{
-    dev::{AppService, HttpServiceFactory, ResourceDef, ServiceRequest, ServiceResponse},
+    dev::{
+        AppService, HttpServiceFactory, RequestHead, ResourceDef, ServiceRequest,
+        ServiceResponse,
+    },
     error::Error,
     guard::Guard,
     http::header::DispositionType,
@@ -13,7 +21,7 @@ use futures_core::future::LocalBoxFuture;
 
 use crate::{
     directory_listing, named, Directory, DirectoryRenderer, FilesService, HttpNewService,
-    MimeOverride,
+    MimeOverride, PathFilter,
 };
 
 /// Static files handling service.
@@ -36,6 +44,7 @@ pub struct Files {
     default: Rc<RefCell<Option<Rc<HttpNewService>>>>,
     renderer: Rc<DirectoryRenderer>,
     mime_override: Option<Rc<MimeOverride>>,
+    path_filter: Option<Rc<PathFilter>>,
     file_flags: named::Flags,
     use_guards: Option<Rc<dyn Guard>>,
     guards: Vec<Rc<dyn Guard>>,
@@ -60,6 +69,7 @@ impl Clone for Files {
             file_flags: self.file_flags,
             path: self.path.clone(),
             mime_override: self.mime_override.clone(),
+            path_filter: self.path_filter.clone(),
             use_guards: self.use_guards.clone(),
             guards: self.guards.clone(),
             hidden_files: self.hidden_files,
@@ -104,6 +114,7 @@ impl Files {
             default: Rc::new(RefCell::new(None)),
             renderer: Rc::new(directory_listing),
             mime_override: None,
+            path_filter: None,
             file_flags: named::Flags::default(),
             use_guards: None,
             guards: Vec::new(),
@@ -114,6 +125,9 @@ impl Files {
     /// Show files listing for directories.
     ///
     /// By default show files listing is disabled.
+    ///
+    /// When used with [`Files::index_file()`], files listing is shown as a fallback
+    /// when the index file is not found.
     pub fn show_files_listing(mut self) -> Self {
         self.show_index = true;
         self
@@ -146,10 +160,45 @@ impl Files {
         self
     }
 
+    /// Sets path filtering closure.
+    ///
+    /// The path provided to the closure is relative to `serve_from` path.
+    /// You can safely join this path with the `serve_from` path to get the real path.
+    /// However, the real path may not exist since the filter is called before checking path existence.
+    ///
+    /// When a path doesn't pass the filter, [`Files::default_handler`] is called if set, otherwise,
+    /// `404 Not Found` is returned.
+    ///
+    /// # Examples
+    /// ```
+    /// use std::path::Path;
+    /// use actix_files::Files;
+    ///
+    /// // prevent searching subdirectories and following symlinks
+    /// let files_service = Files::new("/", "./static").path_filter(|path, _| {
+    ///     path.components().count() == 1
+    ///         && Path::new("./static")
+    ///             .join(path)
+    ///             .symlink_metadata()
+    ///             .map(|m| !m.file_type().is_symlink())
+    ///             .unwrap_or(false)
+    /// });
+    /// ```
+    pub fn path_filter<F>(mut self, f: F) -> Self
+    where
+        F: Fn(&Path, &RequestHead) -> bool + 'static,
+    {
+        self.path_filter = Some(Rc::new(f));
+        self
+    }
+
     /// Set index file
     ///
-    /// Shows specific index file for directory "/" instead of
+    /// Shows specific index file for directories instead of
     /// showing files listing.
+    ///
+    /// If the index file is not found, files listing is shown as a fallback if
+    /// [`Files::show_files_listing()`] is set.
     pub fn index_file<T: Into<String>>(mut self, index: T) -> Self {
         self.index = Some(index.into());
         self
@@ -312,6 +361,7 @@ impl ServiceFactory<ServiceRequest> for Files {
             default: None,
             renderer: self.renderer.clone(),
             mime_override: self.mime_override.clone(),
+            path_filter: self.path_filter.clone(),
             file_flags: self.file_flags,
             guards: self.use_guards.clone(),
             hidden_files: self.hidden_files,
diff --git a/actix-files/src/lib.rs b/actix-files/src/lib.rs
index aa5960b5b..1eb091aaf 100644
--- a/actix-files/src/lib.rs
+++ b/actix-files/src/lib.rs
@@ -16,11 +16,12 @@
 
 use actix_service::boxed::{BoxService, BoxServiceFactory};
 use actix_web::{
-    dev::{ServiceRequest, ServiceResponse},
+    dev::{RequestHead, ServiceRequest, ServiceResponse},
     error::Error,
     http::header::DispositionType,
 };
 use mime_guess::from_ext;
+use std::path::Path;
 
 mod chunked;
 mod directory;
@@ -56,6 +57,8 @@ pub fn file_extension_to_mime(ext: &str) -> mime::Mime {
 
 type MimeOverride = dyn Fn(&mime::Name<'_>) -> DispositionType;
 
+type PathFilter = dyn Fn(&Path, &RequestHead) -> bool;
+
 #[cfg(test)]
 mod tests {
     use std::{
@@ -279,6 +282,22 @@ mod tests {
         );
     }
 
+    #[actix_rt::test]
+    async fn test_named_file_javascript() {
+        let file = NamedFile::open("tests/test.js").unwrap();
+
+        let req = TestRequest::default().to_http_request();
+        let resp = file.respond_to(&req).await.unwrap();
+        assert_eq!(
+            resp.headers().get(header::CONTENT_TYPE).unwrap(),
+            "application/javascript"
+        );
+        assert_eq!(
+            resp.headers().get(header::CONTENT_DISPOSITION).unwrap(),
+            "inline; filename=\"test.js\""
+        );
+    }
+
     #[actix_rt::test]
     async fn test_named_file_image_attachment() {
         let cd = ContentDisposition {
@@ -856,4 +875,69 @@ mod tests {
             "inline; filename=\"symlink-test.png\""
         );
     }
+
+    #[actix_rt::test]
+    async fn test_index_with_show_files_listing() {
+        let service = Files::new(".", ".")
+            .index_file("lib.rs")
+            .show_files_listing()
+            .new_service(())
+            .await
+            .unwrap();
+
+        // Serve the index if exists
+        let req = TestRequest::default().uri("/src").to_srv_request();
+        let resp = test::call_service(&service, req).await;
+        assert_eq!(resp.status(), StatusCode::OK);
+        assert_eq!(
+            resp.headers().get(header::CONTENT_TYPE).unwrap(),
+            "text/x-rust"
+        );
+
+        // Show files listing, otherwise.
+        let req = TestRequest::default().uri("/tests").to_srv_request();
+        let resp = test::call_service(&service, req).await;
+        assert_eq!(
+            resp.headers().get(header::CONTENT_TYPE).unwrap(),
+            "text/html; charset=utf-8"
+        );
+        let bytes = test::read_body(resp).await;
+        assert!(format!("{:?}", bytes).contains("/tests/test.png"));
+    }
+
+    #[actix_rt::test]
+    async fn test_path_filter() {
+        // prevent searching subdirectories
+        let st = Files::new("/", ".")
+            .path_filter(|path, _| path.components().count() == 1)
+            .new_service(())
+            .await
+            .unwrap();
+
+        let req = TestRequest::with_uri("/Cargo.toml").to_srv_request();
+        let resp = test::call_service(&st, req).await;
+        assert_eq!(resp.status(), StatusCode::OK);
+
+        let req = TestRequest::with_uri("/src/lib.rs").to_srv_request();
+        let resp = test::call_service(&st, req).await;
+        assert_eq!(resp.status(), StatusCode::NOT_FOUND);
+    }
+
+    #[actix_rt::test]
+    async fn test_default_handler_filter() {
+        let st = Files::new("/", ".")
+            .default_handler(|req: ServiceRequest| {
+                ok(req.into_response(HttpResponse::Ok().body("default content")))
+            })
+            .path_filter(|path, _| path.extension() == Some("png".as_ref()))
+            .new_service(())
+            .await
+            .unwrap();
+        let req = TestRequest::with_uri("/Cargo.toml").to_srv_request();
+        let resp = test::call_service(&st, req).await;
+
+        assert_eq!(resp.status(), StatusCode::OK);
+        let bytes = test::read_body(resp).await;
+        assert_eq!(bytes, web::Bytes::from_static(b"default content"));
+    }
 }
diff --git a/actix-files/src/named.rs b/actix-files/src/named.rs
index 519234f0d..241e78cf0 100644
--- a/actix-files/src/named.rs
+++ b/actix-files/src/named.rs
@@ -120,6 +120,11 @@ impl NamedFile {
 
             let disposition = match ct.type_() {
                 mime::IMAGE | mime::TEXT | mime::VIDEO => DispositionType::Inline,
+                mime::APPLICATION => match ct.subtype() {
+                    mime::JAVASCRIPT | mime::JSON => DispositionType::Inline,
+                    name if name == "wasm" => DispositionType::Inline,
+                    _ => DispositionType::Attachment,
+                },
                 _ => DispositionType::Attachment,
             };
 
@@ -213,9 +218,11 @@ impl NamedFile {
 
     /// Set the Content-Disposition for serving this file. This allows
     /// changing the inline/attachment disposition as well as the filename
-    /// sent to the peer. By default the disposition is `inline` for text,
-    /// image, and video content types, and `attachment` otherwise, and
-    /// the filename is taken from the path provided in the `open` method
+    /// sent to the peer.
+    ///
+    /// By default the disposition is `inline` for `text/*`, `image/*`, `video/*` and
+    /// `application/{javascript, json, wasm}` mime types, and `attachment` otherwise,
+    /// and the filename is taken from the path provided in the `open` method
     /// after converting it to UTF-8 using.
     /// [`std::ffi::OsStr::to_string_lossy`]
     #[inline]
@@ -235,6 +242,8 @@ impl NamedFile {
     }
 
     /// Set content encoding for serving this file
+    ///
+    /// Must be used with [`actix_web::middleware::Compress`] to take effect.
     #[inline]
     pub fn set_content_encoding(mut self, enc: ContentEncoding) -> Self {
         self.encoding = Some(enc);
@@ -346,8 +355,8 @@ impl NamedFile {
         } else if let (Some(ref m), Some(header::IfUnmodifiedSince(ref since))) =
             (last_modified, req.get_header())
         {
-            let t1: SystemTime = m.clone().into();
-            let t2: SystemTime = since.clone().into();
+            let t1: SystemTime = (*m).into();
+            let t2: SystemTime = (*since).into();
 
             match (t1.duration_since(UNIX_EPOCH), t2.duration_since(UNIX_EPOCH)) {
                 (Ok(t1), Ok(t2)) => t1.as_secs() > t2.as_secs(),
@@ -365,8 +374,8 @@ impl NamedFile {
         } else if let (Some(ref m), Some(header::IfModifiedSince(ref since))) =
             (last_modified, req.get_header())
         {
-            let t1: SystemTime = m.clone().into();
-            let t2: SystemTime = since.clone().into();
+            let t1: SystemTime = (*m).into();
+            let t2: SystemTime = (*since).into();
 
             match (t1.duration_since(UNIX_EPOCH), t2.duration_since(UNIX_EPOCH)) {
                 (Ok(t1), Ok(t2)) => t1.as_secs() <= t2.as_secs(),
diff --git a/actix-files/src/service.rs b/actix-files/src/service.rs
index 831115dc6..09122c63e 100644
--- a/actix-files/src/service.rs
+++ b/actix-files/src/service.rs
@@ -13,7 +13,7 @@ use futures_core::future::LocalBoxFuture;
 
 use crate::{
     named, Directory, DirectoryRenderer, FilesError, HttpService, MimeOverride, NamedFile,
-    PathBufWrap,
+    PathBufWrap, PathFilter,
 };
 
 /// Assembled file serving service.
@@ -25,6 +25,7 @@ pub struct FilesService {
     pub(crate) default: Option<HttpService>,
     pub(crate) renderer: Rc<DirectoryRenderer>,
     pub(crate) mime_override: Option<Rc<MimeOverride>>,
+    pub(crate) path_filter: Option<Rc<PathFilter>>,
     pub(crate) file_flags: named::Flags,
     pub(crate) guards: Option<Rc<dyn Guard>>,
     pub(crate) hidden_files: bool,
@@ -82,6 +83,18 @@ impl Service<ServiceRequest> for FilesService {
                 Err(e) => return Box::pin(ok(req.error_response(e))),
             };
 
+        if let Some(filter) = &self.path_filter {
+            if !filter(real_path.as_ref(), req.head()) {
+                if let Some(ref default) = self.default {
+                    return Box::pin(default.call(req));
+                } else {
+                    return Box::pin(ok(
+                        req.into_response(actix_web::HttpResponse::NotFound().finish())
+                    ));
+                }
+            }
+        }
+
         // full file path
         let path = self.directory.join(&real_path);
         if let Err(err) = path.canonicalize() {
@@ -102,26 +115,20 @@ impl Service<ServiceRequest> for FilesService {
                 )));
             }
 
-            if let Some(ref redir_index) = self.index {
-                let path = path.join(redir_index);
-
-                match NamedFile::open(path) {
-                    Ok(mut named_file) => {
-                        if let Some(ref mime_override) = self.mime_override {
-                            let new_disposition =
-                                mime_override(&named_file.content_type.type_());
-                            named_file.content_disposition.disposition = new_disposition;
-                        }
-                        named_file.flags = self.file_flags;
-
-                        let (req, _) = req.into_parts();
-                        let res = named_file.into_response(&req);
-                        Box::pin(ok(ServiceResponse::new(req, res)))
-                    }
-                    Err(err) => self.handle_err(err, req),
+            let serve_named_file = |req: ServiceRequest, mut named_file: NamedFile| {
+                if let Some(ref mime_override) = self.mime_override {
+                    let new_disposition = mime_override(&named_file.content_type.type_());
+                    named_file.content_disposition.disposition = new_disposition;
                 }
-            } else if self.show_index {
-                let dir = Directory::new(self.directory.clone(), path);
+                named_file.flags = self.file_flags;
+
+                let (req, _) = req.into_parts();
+                let res = named_file.into_response(&req);
+                Box::pin(ok(ServiceResponse::new(req, res)))
+            };
+
+            let show_index = |req: ServiceRequest| {
+                let dir = Directory::new(self.directory.clone(), path.clone());
 
                 let (req, _) = req.into_parts();
                 let x = (self.renderer)(&dir, &req);
@@ -130,11 +137,19 @@ impl Service<ServiceRequest> for FilesService {
                     Ok(resp) => ok(resp),
                     Err(err) => ok(ServiceResponse::from_err(err, req)),
                 })
-            } else {
-                Box::pin(ok(ServiceResponse::from_err(
+            };
+
+            match self.index {
+                Some(ref index) => match NamedFile::open(path.join(index)) {
+                    Ok(named_file) => serve_named_file(req, named_file),
+                    Err(_) if self.show_index => show_index(req),
+                    Err(err) => self.handle_err(err, req),
+                },
+                None if self.show_index => show_index(req),
+                _ => Box::pin(ok(ServiceResponse::from_err(
                     FilesError::IsDirectory,
                     req.into_parts().0,
-                )))
+                ))),
             }
         } else {
             match NamedFile::open(path) {
diff --git a/actix-files/tests/test.js b/actix-files/tests/test.js
new file mode 100644
index 000000000..2ee135561
--- /dev/null
+++ b/actix-files/tests/test.js
@@ -0,0 +1 @@
+// this file is empty.
diff --git a/actix-http-test/Cargo.toml b/actix-http-test/Cargo.toml
index 88b4bd04a..c04b5da49 100644
--- a/actix-http-test/Cargo.toml
+++ b/actix-http-test/Cargo.toml
@@ -35,7 +35,7 @@ actix-tls = "3.0.0-beta.5"
 actix-utils = "3.0.0"
 actix-rt = "2.2"
 actix-server = "2.0.0-beta.3"
-awc = { version = "3.0.0-beta.5", default-features = false }
+awc = { version = "3.0.0-beta.7", default-features = false }
 
 base64 = "0.13"
 bytes = "1"
@@ -51,5 +51,5 @@ time = { version = "0.2.23", default-features = false, features = ["std"] }
 tls-openssl = { version = "0.10.9", package = "openssl", optional = true }
 
 [dev-dependencies]
-actix-web = { version = "4.0.0-beta.6", default-features = false, features = ["cookies"] }
-actix-http = "3.0.0-beta.6"
+actix-web = { version = "4.0.0-beta.8", default-features = false, features = ["cookies"] }
+actix-http = "3.0.0-beta.8"
diff --git a/actix-http-test/README.md b/actix-http-test/README.md
index b8cf450d4..74260a352 100644
--- a/actix-http-test/README.md
+++ b/actix-http-test/README.md
@@ -4,12 +4,14 @@
 
 [![crates.io](https://img.shields.io/crates/v/actix-http-test?label=latest)](https://crates.io/crates/actix-http-test)
 [![Documentation](https://docs.rs/actix-http-test/badge.svg?version=3.0.0-beta.4)](https://docs.rs/actix-http-test/3.0.0-beta.4)
+[![Version](https://img.shields.io/badge/rustc-1.46+-ab6000.svg)](https://blog.rust-lang.org/2020/03/12/Rust-1.46.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-http-test)
+<br>
 [![Dependency Status](https://deps.rs/crate/actix-http-test/3.0.0-beta.4/status.svg)](https://deps.rs/crate/actix-http-test/3.0.0-beta.4)
-[![Join the chat at https://gitter.im/actix/actix-web](https://badges.gitter.im/actix/actix-web.svg)](https://gitter.im/actix/actix-web?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Download](https://img.shields.io/crates/d/actix-http-test.svg)](https://crates.io/crates/actix-http-test)
+[![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
 ## Documentation & Resources
 
 - [API Documentation](https://docs.rs/actix-http-test)
-- [Chat on Gitter](https://gitter.im/actix/actix-web)
 - Minimum Supported Rust Version (MSRV): 1.46.0
diff --git a/actix-http/CHANGES.md b/actix-http/CHANGES.md
index ec7d8ee3b..8ead43718 100644
--- a/actix-http/CHANGES.md
+++ b/actix-http/CHANGES.md
@@ -1,6 +1,20 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+
+
+## 3.0.0-beta.8 - 2021-06-26
+### Changed
+* Change compression algorithm features flags. [#2250]
+
+### Removed
+* `downcast` and `downcast_get_type_id` macros. [#2291]
+
+[#2291]: https://github.com/actix/actix-web/pull/2291
+[#2250]: https://github.com/actix/actix-web/pull/2250
+
+
+## 3.0.0-beta.7 - 2021-06-17
 ### Added
 * Alias `body::Body` as `body::AnyBody`. [#2215]
 * `BoxAnyBody`: a boxed message body with boxed errors. [#2183]
@@ -9,15 +23,20 @@
 * Re-export `ContentEncoding` and `ConnectionType` at the crate root. [#2171]
 * `Response::into_body` that consumes response and returns body type. [#2201]
 * `impl Default` for `Response`. [#2201]
+* Add zstd support for `ContentEncoding`. [#2244]
 
 ### Changed
 * The `MessageBody` trait now has an associated `Error` type. [#2183]
+* All error trait bounds in server service builders have changed from `Into<Error>` to `Into<Response<AnyBody>>`. [#2253]
+* All error trait bounds in message body and stream impls changed from `Into<Error>` to `Into<Box<dyn std::error::Error>>`. [#2253]
 * Places in `Response` where `ResponseBody<B>` was received or returned now simply use `B`. [#2201]
 * `header` mod is now public. [#2171]
 * `uri` mod is now public. [#2171]
 * Update `language-tags` to `0.3`.
 * Reduce the level from `error` to `debug` for the log line that is emitted when a `500 Internal Server Error` is built using `HttpResponse::from_error`. [#2201]
 * `ResponseBuilder::message_body` now returns a `Result`. [#2201]
+* Remove `Unpin` bound on `ResponseBuilder::streaming`. [#2253]
+* `HttpServer::{listen_rustls(), bind_rustls()}` now honor the ALPN protocols in the configuation parameter. [#2226]
 
 ### Removed
 * Stop re-exporting `http` crate's `HeaderMap` types in addition to ours. [#2171]
@@ -35,6 +54,9 @@
 [#2201]: https://github.com/actix/actix-web/pull/2201
 [#2205]: https://github.com/actix/actix-web/pull/2205
 [#2215]: https://github.com/actix/actix-web/pull/2215
+[#2253]: https://github.com/actix/actix-web/pull/2253
+[#2244]: https://github.com/actix/actix-web/pull/2244
+
 
 
 ## 3.0.0-beta.6 - 2021-04-17
diff --git a/actix-http/Cargo.toml b/actix-http/Cargo.toml
index 1f7df39a6..a12fed4b9 100644
--- a/actix-http/Cargo.toml
+++ b/actix-http/Cargo.toml
@@ -1,13 +1,11 @@
 [package]
 name = "actix-http"
-version = "3.0.0-beta.6"
+version = "3.0.0-beta.8"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "HTTP primitives for the Actix ecosystem"
-readme = "README.md"
 keywords = ["actix", "http", "framework", "async", "futures"]
 homepage = "https://actix.rs"
-repository = "https://github.com/actix/actix-web.git"
-documentation = "https://docs.rs/actix-http/"
+repository = "https://github.com/actix/actix-web"
 categories = ["network-programming", "asynchronous",
               "web-programming::http-server",
               "web-programming::websocket"]
@@ -16,7 +14,7 @@ edition = "2018"
 
 [package.metadata.docs.rs]
 # features that docs.rs will build with
-features = ["openssl", "rustls", "compress"]
+features = ["openssl", "rustls", "compress-brotli", "compress-gzip", "compress-zstd"]
 
 [lib]
 name = "actix_http"
@@ -32,11 +30,17 @@ openssl = ["actix-tls/openssl"]
 rustls = ["actix-tls/rustls"]
 
 # enable compression support
-compress = ["flate2", "brotli2"]
+compress-brotli = ["brotli2", "__compress"]
+compress-gzip = ["flate2", "__compress"]
+compress-zstd = ["zstd", "__compress"]
 
 # trust-dns as client dns resolver
 trust-dns = ["trust-dns-resolver"]
 
+# Internal (PRIVATE!) features used to aid testing and cheking feature status.
+# Don't rely on these whatsoever. They may disappear at anytime.
+__compress = []
+
 [dependencies]
 actix-service = "2.0.0"
 actix-codec = "0.4.0"
@@ -76,6 +80,7 @@ tokio = { version = "1.2", features = ["sync"] }
 # compression
 brotli2 = { version="0.3.2", optional = true }
 flate2 = { version = "1.0.13", optional = true }
+zstd = { version = "0.7", optional = true }
 
 trust-dns-resolver = { version = "0.20.0", optional = true }
 
@@ -83,13 +88,15 @@ trust-dns-resolver = { version = "0.20.0", optional = true }
 actix-server = "2.0.0-beta.3"
 actix-http-test = { version = "3.0.0-beta.4", features = ["openssl"] }
 actix-tls = { version = "3.0.0-beta.5", features = ["openssl"] }
-criterion = "0.3"
+async-stream = "0.3"
+criterion = { version = "0.3", features = ["html_reports"] }
 env_logger = "0.8"
 rcgen = "0.8"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 tls-openssl = { version = "0.10", package = "openssl" }
 tls-rustls = { version = "0.19", package = "rustls" }
+webpki = { version = "0.21.0" }
 
 [[example]]
 name = "ws"
diff --git a/actix-http/README.md b/actix-http/README.md
index 87eb38e5d..de1ef0a9b 100644
--- a/actix-http/README.md
+++ b/actix-http/README.md
@@ -3,18 +3,17 @@
 > HTTP primitives for the Actix ecosystem.
 
 [![crates.io](https://img.shields.io/crates/v/actix-http?label=latest)](https://crates.io/crates/actix-http)
-[![Documentation](https://docs.rs/actix-http/badge.svg?version=3.0.0-beta.6)](https://docs.rs/actix-http/3.0.0-beta.6)
+[![Documentation](https://docs.rs/actix-http/badge.svg?version=3.0.0-beta.8)](https://docs.rs/actix-http/3.0.0-beta.8)
 [![Version](https://img.shields.io/badge/rustc-1.46+-ab6000.svg)](https://blog.rust-lang.org/2020/03/12/Rust-1.46.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-http.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-http/3.0.0-beta.6/status.svg)](https://deps.rs/crate/actix-http/3.0.0-beta.6)
+[![dependency status](https://deps.rs/crate/actix-http/3.0.0-beta.8/status.svg)](https://deps.rs/crate/actix-http/3.0.0-beta.8)
 [![Download](https://img.shields.io/crates/d/actix-http.svg)](https://crates.io/crates/actix-http)
-[![Join the chat at https://gitter.im/actix/actix](https://badges.gitter.im/actix/actix.svg)](https://gitter.im/actix/actix?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
 ## Documentation & Resources
 
 - [API Documentation](https://docs.rs/actix-http)
-- [Chat on Gitter](https://gitter.im/actix/actix-web)
 - Minimum Supported Rust Version (MSRV): 1.46.0
 
 ## Example
diff --git a/actix-http/benches/uninit-headers.rs b/actix-http/benches/uninit-headers.rs
index 83e74171c..53a2528ab 100644
--- a/actix-http/benches/uninit-headers.rs
+++ b/actix-http/benches/uninit-headers.rs
@@ -78,12 +78,12 @@ impl HeaderIndex {
 // test cases taken from:
 // https://github.com/seanmonstar/httparse/blob/master/benches/parse.rs
 
-const REQ_SHORT: &'static [u8] = b"\
+const REQ_SHORT: &[u8] = b"\
 GET / HTTP/1.0\r\n\
 Host: example.com\r\n\
 Cookie: session=60; user_id=1\r\n\r\n";
 
-const REQ: &'static [u8] = b"\
+const REQ: &[u8] = b"\
 GET /wp-content/uploads/2010/03/hello-kitty-darth-vader-pink.jpg HTTP/1.1\r\n\
 Host: www.kittyhell.com\r\n\
 User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; ja-JP-mac; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 Pathtraq/0.9\r\n\
@@ -119,6 +119,8 @@ mod _original {
     use std::mem::MaybeUninit;
 
     pub fn parse_headers(src: &mut BytesMut) -> usize {
+        #![allow(clippy::uninit_assumed_init)]
+
         let mut headers: [HeaderIndex; MAX_HEADERS] =
             unsafe { MaybeUninit::uninit().assume_init() };
 
diff --git a/actix-http/examples/echo.rs b/actix-http/examples/echo.rs
index 54a71a106..6cfe3a675 100644
--- a/actix-http/examples/echo.rs
+++ b/actix-http/examples/echo.rs
@@ -5,14 +5,13 @@ use actix_server::Server;
 use bytes::BytesMut;
 use futures_util::StreamExt as _;
 use http::header::HeaderValue;
-use log::info;
 
 #[actix_rt::main]
 async fn main() -> io::Result<()> {
     env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
 
     Server::build()
-        .bind("echo", "127.0.0.1:8080", || {
+        .bind("echo", ("127.0.0.1", 8080), || {
             HttpService::build()
                 .client_timeout(1000)
                 .client_disconnect(1000)
@@ -22,7 +21,8 @@ async fn main() -> io::Result<()> {
                         body.extend_from_slice(&item?);
                     }
 
-                    info!("request body: {:?}", body);
+                    log::info!("request body: {:?}", body);
+
                     Ok::<_, Error>(
                         Response::build(StatusCode::OK)
                             .insert_header((
diff --git a/actix-http/examples/echo2.rs b/actix-http/examples/echo2.rs
index 3974cf20b..db195d65b 100644
--- a/actix-http/examples/echo2.rs
+++ b/actix-http/examples/echo2.rs
@@ -5,7 +5,6 @@ use actix_http::{Error, HttpService, Request, Response};
 use actix_server::Server;
 use bytes::BytesMut;
 use futures_util::StreamExt as _;
-use log::info;
 
 async fn handle_request(mut req: Request) -> Result<Response<Body>, Error> {
     let mut body = BytesMut::new();
@@ -13,7 +12,8 @@ async fn handle_request(mut req: Request) -> Result<Response<Body>, Error> {
         body.extend_from_slice(&item?)
     }
 
-    info!("request body: {:?}", body);
+    log::info!("request body: {:?}", body);
+
     Ok(Response::build(StatusCode::OK)
         .insert_header(("x-head", HeaderValue::from_static("dummy value!")))
         .body(body))
@@ -24,7 +24,7 @@ async fn main() -> io::Result<()> {
     env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
 
     Server::build()
-        .bind("echo", "127.0.0.1:8080", || {
+        .bind("echo", ("127.0.0.1", 8080), || {
             HttpService::build().finish(handle_request).tcp()
         })?
         .run()
diff --git a/actix-http/examples/hello-world.rs b/actix-http/examples/hello-world.rs
index d51de6f4e..9a593c66a 100644
--- a/actix-http/examples/hello-world.rs
+++ b/actix-http/examples/hello-world.rs
@@ -1,28 +1,28 @@
-use std::io;
+use std::{convert::Infallible, io};
 
 use actix_http::{http::StatusCode, HttpService, Response};
 use actix_server::Server;
-use actix_utils::future;
 use http::header::HeaderValue;
-use log::info;
 
 #[actix_rt::main]
 async fn main() -> io::Result<()> {
     env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
 
     Server::build()
-        .bind("hello-world", "127.0.0.1:8080", || {
+        .bind("hello-world", ("127.0.0.1", 8080), || {
             HttpService::build()
                 .client_timeout(1000)
                 .client_disconnect(1000)
-                .finish(|_req| {
-                    info!("{:?}", _req);
+                .finish(|req| async move {
+                    log::info!("{:?}", req);
+
                     let mut res = Response::build(StatusCode::OK);
                     res.insert_header((
                         "x-head",
                         HeaderValue::from_static("dummy value!"),
                     ));
-                    future::ok::<_, ()>(res.body("Hello world!"))
+
+                    Ok::<_, Infallible>(res.body("Hello world!"))
                 })
                 .tcp()
         })?
diff --git a/actix-http/examples/streaming-error.rs b/actix-http/examples/streaming-error.rs
new file mode 100644
index 000000000..3988cbac2
--- /dev/null
+++ b/actix-http/examples/streaming-error.rs
@@ -0,0 +1,40 @@
+//! Example showing response body (chunked) stream erroring.
+//!
+//! Test using `nc` or `curl`.
+//! ```sh
+//! $ curl -vN 127.0.0.1:8080
+//! $ echo 'GET / HTTP/1.1\n\n' | nc 127.0.0.1 8080
+//! ```
+
+use std::{convert::Infallible, io, time::Duration};
+
+use actix_http::{body::BodyStream, HttpService, Response};
+use actix_server::Server;
+use async_stream::stream;
+use bytes::Bytes;
+
+#[actix_rt::main]
+async fn main() -> io::Result<()> {
+    env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
+
+    Server::build()
+        .bind("streaming-error", ("127.0.0.1", 8080), || {
+            HttpService::build()
+                .finish(|req| async move {
+                    log::info!("{:?}", req);
+                    let res = Response::ok();
+
+                    Ok::<_, Infallible>(res.set_body(BodyStream::new(stream! {
+                        yield Ok(Bytes::from("123"));
+                        yield Ok(Bytes::from("456"));
+
+                        actix_rt::time::sleep(Duration::from_millis(1000)).await;
+
+                        yield Err(io::Error::new(io::ErrorKind::Other, ""));
+                    })))
+                })
+                .tcp()
+        })?
+        .run()
+        .await
+}
diff --git a/actix-http/src/body/body.rs b/actix-http/src/body/body.rs
index 3fda8ae11..f04837d07 100644
--- a/actix-http/src/body/body.rs
+++ b/actix-http/src/body/body.rs
@@ -76,7 +76,9 @@ impl MessageBody for AnyBody {
 
             // TODO: MSRV 1.51: poll_map_err
             AnyBody::Message(body) => match ready!(body.as_pin_mut().poll_next(cx)) {
-                Some(Err(err)) => Poll::Ready(Some(Err(err.into()))),
+                Some(Err(err)) => {
+                    Poll::Ready(Some(Err(Error::new_body().with_cause(err))))
+                }
                 Some(Ok(val)) => Poll::Ready(Some(Ok(val))),
                 None => Poll::Ready(None),
             },
@@ -162,9 +164,10 @@ impl From<BytesMut> for AnyBody {
     }
 }
 
-impl<S> From<SizedStream<S>> for AnyBody
+impl<S, E> From<SizedStream<S>> for AnyBody
 where
-    S: Stream<Item = Result<Bytes, Error>> + 'static,
+    S: Stream<Item = Result<Bytes, E>> + 'static,
+    E: Into<Box<dyn StdError>> + 'static,
 {
     fn from(s: SizedStream<S>) -> Body {
         AnyBody::from_message(s)
@@ -174,7 +177,7 @@ where
 impl<S, E> From<BodyStream<S>> for AnyBody
 where
     S: Stream<Item = Result<Bytes, E>> + 'static,
-    E: Into<Error> + 'static,
+    E: Into<Box<dyn StdError>> + 'static,
 {
     fn from(s: BodyStream<S>) -> Body {
         AnyBody::from_message(s)
@@ -222,7 +225,7 @@ impl MessageBody for BoxAnyBody {
     ) -> Poll<Option<Result<Bytes, Self::Error>>> {
         // TODO: MSRV 1.51: poll_map_err
         match ready!(self.0.as_mut().poll_next(cx)) {
-            Some(Err(err)) => Poll::Ready(Some(Err(err.into()))),
+            Some(Err(err)) => Poll::Ready(Some(Err(Error::new_body().with_cause(err)))),
             Some(Ok(val)) => Poll::Ready(Some(Ok(val))),
             None => Poll::Ready(None),
         }
diff --git a/actix-http/src/body/body_stream.rs b/actix-http/src/body/body_stream.rs
index ebe872022..f726f4475 100644
--- a/actix-http/src/body/body_stream.rs
+++ b/actix-http/src/body/body_stream.rs
@@ -1,4 +1,5 @@
 use std::{
+    error::Error as StdError,
     pin::Pin,
     task::{Context, Poll},
 };
@@ -7,8 +8,6 @@ use bytes::Bytes;
 use futures_core::{ready, Stream};
 use pin_project_lite::pin_project;
 
-use crate::error::Error;
-
 use super::{BodySize, MessageBody};
 
 pin_project! {
@@ -24,7 +23,7 @@ pin_project! {
 impl<S, E> BodyStream<S>
 where
     S: Stream<Item = Result<Bytes, E>>,
-    E: Into<Error>,
+    E: Into<Box<dyn StdError>> + 'static,
 {
     pub fn new(stream: S) -> Self {
         BodyStream { stream }
@@ -34,9 +33,9 @@ where
 impl<S, E> MessageBody for BodyStream<S>
 where
     S: Stream<Item = Result<Bytes, E>>,
-    E: Into<Error>,
+    E: Into<Box<dyn StdError>> + 'static,
 {
-    type Error = Error;
+    type Error = E;
 
     fn size(&self) -> BodySize {
         BodySize::Stream
@@ -56,7 +55,7 @@ where
 
             let chunk = match ready!(stream.poll_next(cx)) {
                 Some(Ok(ref bytes)) if bytes.is_empty() => continue,
-                opt => opt.map(|res| res.map_err(Into::into)),
+                opt => opt,
             };
 
             return Poll::Ready(chunk);
@@ -66,9 +65,16 @@ where
 
 #[cfg(test)]
 mod tests {
-    use actix_rt::pin;
+    use std::{convert::Infallible, time::Duration};
+
+    use actix_rt::{
+        pin,
+        time::{sleep, Sleep},
+    };
     use actix_utils::future::poll_fn;
-    use futures_util::stream;
+    use derive_more::{Display, Error};
+    use futures_core::ready;
+    use futures_util::{stream, FutureExt as _};
 
     use super::*;
     use crate::body::to_bytes;
@@ -78,7 +84,7 @@ mod tests {
         let body = BodyStream::new(stream::iter(
             ["1", "", "2"]
                 .iter()
-                .map(|&v| Ok(Bytes::from(v)) as Result<Bytes, ()>),
+                .map(|&v| Ok::<_, Infallible>(Bytes::from(v))),
         ));
         pin!(body);
 
@@ -103,9 +109,63 @@ mod tests {
         let body = BodyStream::new(stream::iter(
             ["1", "", "2"]
                 .iter()
-                .map(|&v| Ok(Bytes::from(v)) as Result<Bytes, ()>),
+                .map(|&v| Ok::<_, Infallible>(Bytes::from(v))),
         ));
 
         assert_eq!(to_bytes(body).await.ok(), Some(Bytes::from("12")));
     }
+    #[derive(Debug, Display, Error)]
+    #[display(fmt = "stream error")]
+    struct StreamErr;
+
+    #[actix_rt::test]
+    async fn stream_immediate_error() {
+        let body = BodyStream::new(stream::once(async { Err(StreamErr) }));
+        assert!(matches!(to_bytes(body).await, Err(StreamErr)));
+    }
+
+    #[actix_rt::test]
+    async fn stream_delayed_error() {
+        let body =
+            BodyStream::new(stream::iter(vec![Ok(Bytes::from("1")), Err(StreamErr)]));
+        assert!(matches!(to_bytes(body).await, Err(StreamErr)));
+
+        #[pin_project::pin_project(project = TimeDelayStreamProj)]
+        #[derive(Debug)]
+        enum TimeDelayStream {
+            Start,
+            Sleep(Pin<Box<Sleep>>),
+            Done,
+        }
+
+        impl Stream for TimeDelayStream {
+            type Item = Result<Bytes, StreamErr>;
+
+            fn poll_next(
+                mut self: Pin<&mut Self>,
+                cx: &mut Context<'_>,
+            ) -> Poll<Option<Self::Item>> {
+                match self.as_mut().get_mut() {
+                    TimeDelayStream::Start => {
+                        let sleep = sleep(Duration::from_millis(1));
+                        self.as_mut().set(TimeDelayStream::Sleep(Box::pin(sleep)));
+                        cx.waker().wake_by_ref();
+                        Poll::Pending
+                    }
+
+                    TimeDelayStream::Sleep(ref mut delay) => {
+                        ready!(delay.poll_unpin(cx));
+                        self.set(TimeDelayStream::Done);
+                        cx.waker().wake_by_ref();
+                        Poll::Pending
+                    }
+
+                    TimeDelayStream::Done => Poll::Ready(Some(Err(StreamErr))),
+                }
+            }
+        }
+
+        let body = BodyStream::new(TimeDelayStream::Start);
+        assert!(matches!(to_bytes(body).await, Err(StreamErr)));
+    }
 }
diff --git a/actix-http/src/body/mod.rs b/actix-http/src/body/mod.rs
index 11aff039e..8a08dbd2b 100644
--- a/actix-http/src/body/mod.rs
+++ b/actix-http/src/body/mod.rs
@@ -191,11 +191,15 @@ mod tests {
     }
 
     #[actix_rt::test]
-    async fn test_box() {
+    async fn test_box_and_pin() {
         let val = Box::new(());
         pin!(val);
         assert_eq!(val.size(), BodySize::Empty);
         assert!(poll_fn(|cx| val.as_mut().poll_next(cx)).await.is_none());
+
+        let mut val = Box::pin(());
+        assert_eq!(val.size(), BodySize::Empty);
+        assert!(poll_fn(|cx| val.as_mut().poll_next(cx)).await.is_none());
     }
 
     #[actix_rt::test]
diff --git a/actix-http/src/body/sized_stream.rs b/actix-http/src/body/sized_stream.rs
index 4af132389..b6ceb32fe 100644
--- a/actix-http/src/body/sized_stream.rs
+++ b/actix-http/src/body/sized_stream.rs
@@ -1,4 +1,5 @@
 use std::{
+    error::Error as StdError,
     pin::Pin,
     task::{Context, Poll},
 };
@@ -7,15 +8,13 @@ use bytes::Bytes;
 use futures_core::{ready, Stream};
 use pin_project_lite::pin_project;
 
-use crate::error::Error;
-
 use super::{BodySize, MessageBody};
 
 pin_project! {
     /// Known sized streaming response wrapper.
     ///
-    /// This body implementation should be used if total size of stream is known. Data get sent as is
-    /// without using transfer encoding.
+    /// This body implementation should be used if total size of stream is known. Data is sent as-is
+    /// without using chunked transfer encoding.
     pub struct SizedStream<S> {
         size: u64,
         #[pin]
@@ -23,20 +22,22 @@ pin_project! {
     }
 }
 
-impl<S> SizedStream<S>
+impl<S, E> SizedStream<S>
 where
-    S: Stream<Item = Result<Bytes, Error>>,
+    S: Stream<Item = Result<Bytes, E>>,
+    E: Into<Box<dyn StdError>> + 'static,
 {
     pub fn new(size: u64, stream: S) -> Self {
         SizedStream { size, stream }
     }
 }
 
-impl<S> MessageBody for SizedStream<S>
+impl<S, E> MessageBody for SizedStream<S>
 where
-    S: Stream<Item = Result<Bytes, Error>>,
+    S: Stream<Item = Result<Bytes, E>>,
+    E: Into<Box<dyn StdError>> + 'static,
 {
-    type Error = Error;
+    type Error = E;
 
     fn size(&self) -> BodySize {
         BodySize::Sized(self.size as u64)
@@ -66,6 +67,8 @@ where
 
 #[cfg(test)]
 mod tests {
+    use std::convert::Infallible;
+
     use actix_rt::pin;
     use actix_utils::future::poll_fn;
     use futures_util::stream;
@@ -77,7 +80,11 @@ mod tests {
     async fn skips_empty_chunks() {
         let body = SizedStream::new(
             2,
-            stream::iter(["1", "", "2"].iter().map(|&v| Ok(Bytes::from(v)))),
+            stream::iter(
+                ["1", "", "2"]
+                    .iter()
+                    .map(|&v| Ok::<_, Infallible>(Bytes::from(v))),
+            ),
         );
 
         pin!(body);
@@ -103,7 +110,11 @@ mod tests {
     async fn read_to_bytes() {
         let body = SizedStream::new(
             2,
-            stream::iter(["1", "", "2"].iter().map(|&v| Ok(Bytes::from(v)))),
+            stream::iter(
+                ["1", "", "2"]
+                    .iter()
+                    .map(|&v| Ok::<_, Infallible>(Bytes::from(v))),
+            ),
         );
 
         assert_eq!(to_bytes(body).await.ok(), Some(Bytes::from("12")));
diff --git a/actix-http/src/builder.rs b/actix-http/src/builder.rs
index 660cd9817..4e68dc920 100644
--- a/actix-http/src/builder.rs
+++ b/actix-http/src/builder.rs
@@ -1,19 +1,16 @@
-use std::marker::PhantomData;
-use std::rc::Rc;
-use std::{fmt, net};
+use std::{error::Error as StdError, fmt, marker::PhantomData, net, rc::Rc};
 
 use actix_codec::Framed;
 use actix_service::{IntoServiceFactory, Service, ServiceFactory};
 
-use crate::body::MessageBody;
-use crate::config::{KeepAlive, ServiceConfig};
-use crate::error::Error;
-use crate::h1::{Codec, ExpectHandler, H1Service, UpgradeHandler};
-use crate::h2::H2Service;
-use crate::request::Request;
-use crate::response::Response;
-use crate::service::HttpService;
-use crate::{ConnectCallback, Extensions};
+use crate::{
+    body::{AnyBody, MessageBody},
+    config::{KeepAlive, ServiceConfig},
+    h1::{self, ExpectHandler, H1Service, UpgradeHandler},
+    h2::H2Service,
+    service::HttpService,
+    ConnectCallback, Extensions, Request, Response,
+};
 
 /// A HTTP service builder
 ///
@@ -34,7 +31,7 @@ pub struct HttpServiceBuilder<T, S, X = ExpectHandler, U = UpgradeHandler> {
 impl<T, S> HttpServiceBuilder<T, S, ExpectHandler, UpgradeHandler>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::InitError: fmt::Debug,
     <S::Service as Service<Request>>::Future: 'static,
 {
@@ -57,13 +54,13 @@ where
 impl<T, S, X, U> HttpServiceBuilder<T, S, X, U>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::InitError: fmt::Debug,
     <S::Service as Service<Request>>::Future: 'static,
     X: ServiceFactory<Request, Config = (), Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
     X::InitError: fmt::Debug,
-    U: ServiceFactory<(Request, Framed<T, Codec>), Config = (), Response = ()>,
+    U: ServiceFactory<(Request, Framed<T, h1::Codec>), Config = (), Response = ()>,
     U::Error: fmt::Display,
     U::InitError: fmt::Debug,
 {
@@ -123,7 +120,7 @@ where
     where
         F: IntoServiceFactory<X1, Request>,
         X1: ServiceFactory<Request, Config = (), Response = Request>,
-        X1::Error: Into<Error>,
+        X1::Error: Into<Response<AnyBody>>,
         X1::InitError: fmt::Debug,
     {
         HttpServiceBuilder {
@@ -145,8 +142,8 @@ where
     /// and this service get called with original request and framed object.
     pub fn upgrade<F, U1>(self, upgrade: F) -> HttpServiceBuilder<T, S, X, U1>
     where
-        F: IntoServiceFactory<U1, (Request, Framed<T, Codec>)>,
-        U1: ServiceFactory<(Request, Framed<T, Codec>), Config = (), Response = ()>,
+        F: IntoServiceFactory<U1, (Request, Framed<T, h1::Codec>)>,
+        U1: ServiceFactory<(Request, Framed<T, h1::Codec>), Config = (), Response = ()>,
         U1::Error: fmt::Display,
         U1::InitError: fmt::Debug,
     {
@@ -181,7 +178,7 @@ where
     where
         B: MessageBody,
         F: IntoServiceFactory<S, Request>,
-        S::Error: Into<Error>,
+        S::Error: Into<Response<AnyBody>>,
         S::InitError: fmt::Debug,
         S::Response: Into<Response<B>>,
     {
@@ -203,12 +200,12 @@ where
     pub fn h2<F, B>(self, service: F) -> H2Service<T, S, B>
     where
         F: IntoServiceFactory<S, Request>,
-        S::Error: Into<Error> + 'static,
+        S::Error: Into<Response<AnyBody>> + 'static,
         S::InitError: fmt::Debug,
         S::Response: Into<Response<B>> + 'static,
 
         B: MessageBody + 'static,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
     {
         let cfg = ServiceConfig::new(
             self.keep_alive,
@@ -226,12 +223,12 @@ where
     pub fn finish<F, B>(self, service: F) -> HttpService<T, S, B, X, U>
     where
         F: IntoServiceFactory<S, Request>,
-        S::Error: Into<Error> + 'static,
+        S::Error: Into<Response<AnyBody>> + 'static,
         S::InitError: fmt::Debug,
         S::Response: Into<Response<B>> + 'static,
 
         B: MessageBody + 'static,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
     {
         let cfg = ServiceConfig::new(
             self.keep_alive,
diff --git a/actix-http/src/client/connector.rs b/actix-http/src/client/connector.rs
index 508fe748b..bd46919e8 100644
--- a/actix-http/src/client/connector.rs
+++ b/actix-http/src/client/connector.rs
@@ -85,7 +85,7 @@ impl Connector<()> {
         use bytes::{BufMut, BytesMut};
 
         let mut alpn = BytesMut::with_capacity(20);
-        for proto in protocols.iter() {
+        for proto in &protocols {
             alpn.put_u8(proto.len() as u8);
             alpn.put(proto.as_slice());
         }
@@ -290,8 +290,7 @@ where
                         let h2 = sock
                             .ssl()
                             .selected_alpn_protocol()
-                            .map(|protos| protos.windows(2).any(|w| w == H2))
-                            .unwrap_or(false);
+                            .map_or(false, |protos| protos.windows(2).any(|w| w == H2));
                         if h2 {
                             (Box::new(sock), Protocol::Http2)
                         } else {
@@ -325,8 +324,7 @@ where
                             .get_ref()
                             .1
                             .get_alpn_protocol()
-                            .map(|protos| protos.windows(2).any(|w| w == H2))
-                            .unwrap_or(false);
+                            .map_or(false, |protos| protos.windows(2).any(|w| w == H2));
                         if h2 {
                             (Box::new(sock), Protocol::Http2)
                         } else {
diff --git a/actix-http/src/client/error.rs b/actix-http/src/client/error.rs
index d27363456..34833503b 100644
--- a/actix-http/src/client/error.rs
+++ b/actix-http/src/client/error.rs
@@ -1,15 +1,16 @@
-use std::io;
+use std::{error::Error as StdError, fmt, io};
 
 use derive_more::{Display, From};
 
 #[cfg(feature = "openssl")]
 use actix_tls::accept::openssl::SslError;
 
-use crate::error::{Error, ParseError, ResponseError};
-use crate::http::{Error as HttpError, StatusCode};
+use crate::error::{Error, ParseError};
+use crate::http::Error as HttpError;
 
 /// A set of errors that can occur while connecting to an HTTP host
 #[derive(Debug, Display, From)]
+#[non_exhaustive]
 pub enum ConnectError {
     /// SSL feature is not enabled
     #[display(fmt = "SSL is not supported")]
@@ -64,6 +65,7 @@ impl From<actix_tls::connect::ConnectError> for ConnectError {
 }
 
 #[derive(Debug, Display, From)]
+#[non_exhaustive]
 pub enum InvalidUrl {
     #[display(fmt = "Missing URL scheme")]
     MissingScheme,
@@ -82,6 +84,7 @@ impl std::error::Error for InvalidUrl {}
 
 /// A set of errors that can occur during request sending and response reading
 #[derive(Debug, Display, From)]
+#[non_exhaustive]
 pub enum SendRequestError {
     /// Invalid URL
     #[display(fmt = "Invalid URL: {}", _0)]
@@ -115,25 +118,17 @@ pub enum SendRequestError {
 
     /// Error sending request body
     Body(Error),
+
+    /// Other errors that can occur after submitting a request.
+    #[display(fmt = "{:?}: {}", _1, _0)]
+    Custom(Box<dyn StdError>, Box<dyn fmt::Debug>),
 }
 
 impl std::error::Error for SendRequestError {}
 
-/// Convert `SendRequestError` to a server `Response`
-impl ResponseError for SendRequestError {
-    fn status_code(&self) -> StatusCode {
-        match *self {
-            SendRequestError::Connect(ConnectError::Timeout) => {
-                StatusCode::GATEWAY_TIMEOUT
-            }
-            SendRequestError::Connect(_) => StatusCode::BAD_REQUEST,
-            _ => StatusCode::INTERNAL_SERVER_ERROR,
-        }
-    }
-}
-
 /// A set of errors that can occur during freezing a request
 #[derive(Debug, Display, From)]
+#[non_exhaustive]
 pub enum FreezeRequestError {
     /// Invalid URL
     #[display(fmt = "Invalid URL: {}", _0)]
@@ -142,15 +137,20 @@ pub enum FreezeRequestError {
     /// HTTP error
     #[display(fmt = "{}", _0)]
     Http(HttpError),
+
+    /// Other errors that can occur after submitting a request.
+    #[display(fmt = "{:?}: {}", _1, _0)]
+    Custom(Box<dyn StdError>, Box<dyn fmt::Debug>),
 }
 
 impl std::error::Error for FreezeRequestError {}
 
 impl From<FreezeRequestError> for SendRequestError {
-    fn from(e: FreezeRequestError) -> Self {
-        match e {
-            FreezeRequestError::Url(e) => e.into(),
-            FreezeRequestError::Http(e) => e.into(),
+    fn from(err: FreezeRequestError) -> Self {
+        match err {
+            FreezeRequestError::Url(err) => err.into(),
+            FreezeRequestError::Http(err) => err.into(),
+            FreezeRequestError::Custom(err, msg) => SendRequestError::Custom(err, msg),
         }
     }
 }
diff --git a/actix-http/src/client/h2proto.rs b/actix-http/src/client/h2proto.rs
index cf423ef12..b9d5f96bd 100644
--- a/actix-http/src/client/h2proto.rs
+++ b/actix-http/src/client/h2proto.rs
@@ -168,14 +168,13 @@ where
 
                 if let Err(e) = send.send_data(bytes, false) {
                     return Err(e.into());
-                } else {
-                    if !b.is_empty() {
-                        send.reserve_capacity(b.len());
-                    } else {
-                        buf = None;
-                    }
-                    continue;
                 }
+                if !b.is_empty() {
+                    send.reserve_capacity(b.len());
+                } else {
+                    buf = None;
+                }
+                continue;
             }
             Some(Err(e)) => return Err(e.into()),
         }
diff --git a/actix-http/src/config.rs b/actix-http/src/config.rs
index 9a2293e92..0e01e8748 100644
--- a/actix-http/src/config.rs
+++ b/actix-http/src/config.rs
@@ -152,8 +152,8 @@ impl ServiceConfig {
         }
     }
 
-    #[inline]
     /// Return keep-alive timer delay is configured.
+    #[inline]
     pub fn keep_alive_timer(&self) -> Option<Sleep> {
         self.keep_alive().map(|ka| sleep_until(self.now() + ka))
     }
@@ -365,11 +365,11 @@ mod tests {
         let clone3 = service.clone();
 
         drop(clone1);
-        assert_eq!(false, notify_on_drop::is_dropped());
+        assert!(!notify_on_drop::is_dropped());
         drop(clone2);
-        assert_eq!(false, notify_on_drop::is_dropped());
+        assert!(!notify_on_drop::is_dropped());
         drop(clone3);
-        assert_eq!(false, notify_on_drop::is_dropped());
+        assert!(!notify_on_drop::is_dropped());
 
         drop(service);
         assert!(notify_on_drop::is_dropped());
diff --git a/actix-http/src/encoding/decoder.rs b/actix-http/src/encoding/decoder.rs
index f0abae865..d3e304836 100644
--- a/actix-http/src/encoding/decoder.rs
+++ b/actix-http/src/encoding/decoder.rs
@@ -8,11 +8,18 @@ use std::{
 };
 
 use actix_rt::task::{spawn_blocking, JoinHandle};
-use brotli2::write::BrotliDecoder;
 use bytes::Bytes;
-use flate2::write::{GzDecoder, ZlibDecoder};
 use futures_core::{ready, Stream};
 
+#[cfg(feature = "compress-brotli")]
+use brotli2::write::BrotliDecoder;
+
+#[cfg(feature = "compress-gzip")]
+use flate2::write::{GzDecoder, ZlibDecoder};
+
+#[cfg(feature = "compress-zstd")]
+use zstd::stream::write::Decoder as ZstdDecoder;
+
 use crate::{
     encoding::Writer,
     error::{BlockingError, PayloadError},
@@ -36,15 +43,25 @@ where
     #[inline]
     pub fn new(stream: S, encoding: ContentEncoding) -> Decoder<S> {
         let decoder = match encoding {
+            #[cfg(feature = "compress-brotli")]
             ContentEncoding::Br => Some(ContentDecoder::Br(Box::new(
                 BrotliDecoder::new(Writer::new()),
             ))),
+            #[cfg(feature = "compress-gzip")]
             ContentEncoding::Deflate => Some(ContentDecoder::Deflate(Box::new(
                 ZlibDecoder::new(Writer::new()),
             ))),
+            #[cfg(feature = "compress-gzip")]
             ContentEncoding::Gzip => Some(ContentDecoder::Gzip(Box::new(
                 GzDecoder::new(Writer::new()),
             ))),
+            #[cfg(feature = "compress-zstd")]
+            ContentEncoding::Zstd => Some(ContentDecoder::Zstd(Box::new(
+                ZstdDecoder::new(Writer::new()).expect(
+                    "Failed to create zstd decoder. This is a bug. \
+                         Please report it to the actix-web repository.",
+                ),
+            ))),
             _ => None,
         };
 
@@ -141,14 +158,22 @@ where
 }
 
 enum ContentDecoder {
+    #[cfg(feature = "compress-gzip")]
     Deflate(Box<ZlibDecoder<Writer>>),
+    #[cfg(feature = "compress-gzip")]
     Gzip(Box<GzDecoder<Writer>>),
+    #[cfg(feature = "compress-brotli")]
     Br(Box<BrotliDecoder<Writer>>),
+    // We need explicit 'static lifetime here because ZstdDecoder need lifetime
+    // argument, and we use `spawn_blocking` in `Decoder::poll_next` that require `FnOnce() -> R + Send + 'static`
+    #[cfg(feature = "compress-zstd")]
+    Zstd(Box<ZstdDecoder<'static, Writer>>),
 }
 
 impl ContentDecoder {
     fn feed_eof(&mut self) -> io::Result<Option<Bytes>> {
         match self {
+            #[cfg(feature = "compress-brotli")]
             ContentDecoder::Br(ref mut decoder) => match decoder.flush() {
                 Ok(()) => {
                     let b = decoder.get_mut().take();
@@ -162,6 +187,7 @@ impl ContentDecoder {
                 Err(e) => Err(e),
             },
 
+            #[cfg(feature = "compress-gzip")]
             ContentDecoder::Gzip(ref mut decoder) => match decoder.try_finish() {
                 Ok(_) => {
                     let b = decoder.get_mut().take();
@@ -175,6 +201,7 @@ impl ContentDecoder {
                 Err(e) => Err(e),
             },
 
+            #[cfg(feature = "compress-gzip")]
             ContentDecoder::Deflate(ref mut decoder) => match decoder.try_finish() {
                 Ok(_) => {
                     let b = decoder.get_mut().take();
@@ -186,11 +213,25 @@ impl ContentDecoder {
                 }
                 Err(e) => Err(e),
             },
+
+            #[cfg(feature = "compress-zstd")]
+            ContentDecoder::Zstd(ref mut decoder) => match decoder.flush() {
+                Ok(_) => {
+                    let b = decoder.get_mut().take();
+                    if !b.is_empty() {
+                        Ok(Some(b))
+                    } else {
+                        Ok(None)
+                    }
+                }
+                Err(e) => Err(e),
+            },
         }
     }
 
     fn feed_data(&mut self, data: Bytes) -> io::Result<Option<Bytes>> {
         match self {
+            #[cfg(feature = "compress-brotli")]
             ContentDecoder::Br(ref mut decoder) => match decoder.write_all(&data) {
                 Ok(_) => {
                     decoder.flush()?;
@@ -205,6 +246,7 @@ impl ContentDecoder {
                 Err(e) => Err(e),
             },
 
+            #[cfg(feature = "compress-gzip")]
             ContentDecoder::Gzip(ref mut decoder) => match decoder.write_all(&data) {
                 Ok(_) => {
                     decoder.flush()?;
@@ -219,6 +261,7 @@ impl ContentDecoder {
                 Err(e) => Err(e),
             },
 
+            #[cfg(feature = "compress-gzip")]
             ContentDecoder::Deflate(ref mut decoder) => match decoder.write_all(&data) {
                 Ok(_) => {
                     decoder.flush()?;
@@ -232,6 +275,21 @@ impl ContentDecoder {
                 }
                 Err(e) => Err(e),
             },
+
+            #[cfg(feature = "compress-zstd")]
+            ContentDecoder::Zstd(ref mut decoder) => match decoder.write_all(&data) {
+                Ok(_) => {
+                    decoder.flush()?;
+
+                    let b = decoder.get_mut().take();
+                    if !b.is_empty() {
+                        Ok(Some(b))
+                    } else {
+                        Ok(None)
+                    }
+                }
+                Err(e) => Err(e),
+            },
         }
     }
 }
diff --git a/actix-http/src/encoding/encoder.rs b/actix-http/src/encoding/encoder.rs
index b8bc8b68d..1e69990a0 100644
--- a/actix-http/src/encoding/encoder.rs
+++ b/actix-http/src/encoding/encoder.rs
@@ -9,13 +9,20 @@ use std::{
 };
 
 use actix_rt::task::{spawn_blocking, JoinHandle};
-use brotli2::write::BrotliEncoder;
 use bytes::Bytes;
 use derive_more::Display;
-use flate2::write::{GzEncoder, ZlibEncoder};
 use futures_core::ready;
 use pin_project::pin_project;
 
+#[cfg(feature = "compress-brotli")]
+use brotli2::write::BrotliEncoder;
+
+#[cfg(feature = "compress-gzip")]
+use flate2::write::{GzEncoder, ZlibEncoder};
+
+#[cfg(feature = "compress-zstd")]
+use zstd::stream::write::Encoder as ZstdEncoder;
+
 use crate::{
     body::{Body, BodySize, BoxAnyBody, MessageBody, ResponseBody},
     http::{
@@ -132,9 +139,7 @@ where
             },
             EncoderBodyProj::BoxedStream(ref mut b) => {
                 match ready!(b.as_pin_mut().poll_next(cx)) {
-                    Some(Err(err)) => {
-                        Poll::Ready(Some(Err(EncoderError::Boxed(err.into()))))
-                    }
+                    Some(Err(err)) => Poll::Ready(Some(Err(EncoderError::Boxed(err)))),
                     Some(Ok(val)) => Poll::Ready(Some(Ok(val))),
                     None => Poll::Ready(None),
                 }
@@ -234,25 +239,40 @@ fn update_head(encoding: ContentEncoding, head: &mut ResponseHead) {
 }
 
 enum ContentEncoder {
+    #[cfg(feature = "compress-gzip")]
     Deflate(ZlibEncoder<Writer>),
+    #[cfg(feature = "compress-gzip")]
     Gzip(GzEncoder<Writer>),
+    #[cfg(feature = "compress-brotli")]
     Br(BrotliEncoder<Writer>),
+    // We need explicit 'static lifetime here because ZstdEncoder need lifetime
+    // argument, and we use `spawn_blocking` in `Encoder::poll_next` that require `FnOnce() -> R + Send + 'static`
+    #[cfg(feature = "compress-zstd")]
+    Zstd(ZstdEncoder<'static, Writer>),
 }
 
 impl ContentEncoder {
     fn encoder(encoding: ContentEncoding) -> Option<Self> {
         match encoding {
+            #[cfg(feature = "compress-gzip")]
             ContentEncoding::Deflate => Some(ContentEncoder::Deflate(ZlibEncoder::new(
                 Writer::new(),
                 flate2::Compression::fast(),
             ))),
+            #[cfg(feature = "compress-gzip")]
             ContentEncoding::Gzip => Some(ContentEncoder::Gzip(GzEncoder::new(
                 Writer::new(),
                 flate2::Compression::fast(),
             ))),
+            #[cfg(feature = "compress-brotli")]
             ContentEncoding::Br => {
                 Some(ContentEncoder::Br(BrotliEncoder::new(Writer::new(), 3)))
             }
+            #[cfg(feature = "compress-zstd")]
+            ContentEncoding::Zstd => {
+                let encoder = ZstdEncoder::new(Writer::new(), 3).ok()?;
+                Some(ContentEncoder::Zstd(encoder))
+            }
             _ => None,
         }
     }
@@ -260,31 +280,45 @@ impl ContentEncoder {
     #[inline]
     pub(crate) fn take(&mut self) -> Bytes {
         match *self {
+            #[cfg(feature = "compress-brotli")]
             ContentEncoder::Br(ref mut encoder) => encoder.get_mut().take(),
+            #[cfg(feature = "compress-gzip")]
             ContentEncoder::Deflate(ref mut encoder) => encoder.get_mut().take(),
+            #[cfg(feature = "compress-gzip")]
             ContentEncoder::Gzip(ref mut encoder) => encoder.get_mut().take(),
+            #[cfg(feature = "compress-zstd")]
+            ContentEncoder::Zstd(ref mut encoder) => encoder.get_mut().take(),
         }
     }
 
     fn finish(self) -> Result<Bytes, io::Error> {
         match self {
+            #[cfg(feature = "compress-brotli")]
             ContentEncoder::Br(encoder) => match encoder.finish() {
                 Ok(writer) => Ok(writer.buf.freeze()),
                 Err(err) => Err(err),
             },
+            #[cfg(feature = "compress-gzip")]
             ContentEncoder::Gzip(encoder) => match encoder.finish() {
                 Ok(writer) => Ok(writer.buf.freeze()),
                 Err(err) => Err(err),
             },
+            #[cfg(feature = "compress-gzip")]
             ContentEncoder::Deflate(encoder) => match encoder.finish() {
                 Ok(writer) => Ok(writer.buf.freeze()),
                 Err(err) => Err(err),
             },
+            #[cfg(feature = "compress-zstd")]
+            ContentEncoder::Zstd(encoder) => match encoder.finish() {
+                Ok(writer) => Ok(writer.buf.freeze()),
+                Err(err) => Err(err),
+            },
         }
     }
 
     fn write(&mut self, data: &[u8]) -> Result<(), io::Error> {
         match *self {
+            #[cfg(feature = "compress-brotli")]
             ContentEncoder::Br(ref mut encoder) => match encoder.write_all(data) {
                 Ok(_) => Ok(()),
                 Err(err) => {
@@ -292,6 +326,7 @@ impl ContentEncoder {
                     Err(err)
                 }
             },
+            #[cfg(feature = "compress-gzip")]
             ContentEncoder::Gzip(ref mut encoder) => match encoder.write_all(data) {
                 Ok(_) => Ok(()),
                 Err(err) => {
@@ -299,6 +334,7 @@ impl ContentEncoder {
                     Err(err)
                 }
             },
+            #[cfg(feature = "compress-gzip")]
             ContentEncoder::Deflate(ref mut encoder) => match encoder.write_all(data) {
                 Ok(_) => Ok(()),
                 Err(err) => {
@@ -306,6 +342,14 @@ impl ContentEncoder {
                     Err(err)
                 }
             },
+            #[cfg(feature = "compress-zstd")]
+            ContentEncoder::Zstd(ref mut encoder) => match encoder.write_all(data) {
+                Ok(_) => Ok(()),
+                Err(err) => {
+                    trace!("Error decoding ztsd encoding: {}", err);
+                    Err(err)
+                }
+            },
         }
     }
 }
@@ -317,7 +361,7 @@ pub enum EncoderError<E> {
     Body(E),
 
     #[display(fmt = "boxed")]
-    Boxed(Error),
+    Boxed(Box<dyn StdError>),
 
     #[display(fmt = "blocking")]
     Blocking(BlockingError),
@@ -326,19 +370,19 @@ pub enum EncoderError<E> {
     Io(io::Error),
 }
 
-impl<E: StdError> StdError for EncoderError<E> {
+impl<E: StdError + 'static> StdError for EncoderError<E> {
     fn source(&self) -> Option<&(dyn StdError + 'static)> {
-        None
-    }
-}
-
-impl<E: Into<Error>> From<EncoderError<E>> for Error {
-    fn from(err: EncoderError<E>) -> Self {
-        match err {
-            EncoderError::Body(err) => err.into(),
-            EncoderError::Boxed(err) => err,
-            EncoderError::Blocking(err) => err.into(),
-            EncoderError::Io(err) => err.into(),
+        match self {
+            EncoderError::Body(err) => Some(err),
+            EncoderError::Boxed(err) => Some(&**err),
+            EncoderError::Blocking(err) => Some(err),
+            EncoderError::Io(err) => Some(err),
         }
     }
 }
+
+impl<E: StdError + 'static> From<EncoderError<E>> for crate::Error {
+    fn from(err: EncoderError<E>) -> Self {
+        crate::Error::new_encoder().with_cause(err)
+    }
+}
diff --git a/actix-http/src/error.rs b/actix-http/src/error.rs
index 92efd572d..6c3d692c3 100644
--- a/actix-http/src/error.rs
+++ b/actix-http/src/error.rs
@@ -1,174 +1,155 @@
 //! Error and Result module
 
-use std::{
-    error::Error as StdError,
-    fmt,
-    io::{self, Write as _},
-    str::Utf8Error,
-    string::FromUtf8Error,
-};
+use std::{error::Error as StdError, fmt, io, str::Utf8Error, string::FromUtf8Error};
 
-use bytes::BytesMut;
 use derive_more::{Display, Error, From};
-use http::{header, uri::InvalidUri, StatusCode};
-use serde::de::value::Error as DeError;
+use http::{uri::InvalidUri, StatusCode};
 
-use crate::{body::Body, helpers::Writer, Response};
+use crate::{
+    body::{AnyBody, Body},
+    ws, Response,
+};
 
 pub use http::Error as HttpError;
 
-/// General purpose actix web error.
-///
-/// An actix web error is used to carry errors from `std::error`
-/// through actix in a convenient way.  It can be created through
-/// converting errors with `into()`.
-///
-/// Whenever it is created from an external object a response error is created
-/// for it that can be used to create an HTTP response from it this means that
-/// if you have access to an actix `Error` you can always get a
-/// `ResponseError` reference from it.
 pub struct Error {
-    cause: Box<dyn ResponseError>,
+    inner: Box<ErrorInner>,
+}
+
+pub(crate) struct ErrorInner {
+    #[allow(dead_code)]
+    kind: Kind,
+    cause: Option<Box<dyn StdError>>,
 }
 
 impl Error {
-    /// Returns the reference to the underlying `ResponseError`.
-    pub fn as_response_error(&self) -> &dyn ResponseError {
-        self.cause.as_ref()
+    fn new(kind: Kind) -> Self {
+        Self {
+            inner: Box::new(ErrorInner { kind, cause: None }),
+        }
     }
 
-    /// Similar to `as_response_error` but downcasts.
-    pub fn as_error<T: ResponseError + 'static>(&self) -> Option<&T> {
-        <dyn ResponseError>::downcast_ref(self.cause.as_ref())
+    pub(crate) fn new_http() -> Self {
+        Self::new(Kind::Http)
+    }
+
+    pub(crate) fn new_parse() -> Self {
+        Self::new(Kind::Parse)
+    }
+
+    pub(crate) fn new_payload() -> Self {
+        Self::new(Kind::Payload)
+    }
+
+    pub(crate) fn new_body() -> Self {
+        Self::new(Kind::Body)
+    }
+
+    pub(crate) fn new_send_response() -> Self {
+        Self::new(Kind::SendResponse)
+    }
+
+    // TODO: remove allow
+    #[allow(dead_code)]
+    pub(crate) fn new_io() -> Self {
+        Self::new(Kind::Io)
+    }
+
+    pub(crate) fn new_encoder() -> Self {
+        Self::new(Kind::Encoder)
+    }
+
+    pub(crate) fn new_ws() -> Self {
+        Self::new(Kind::Ws)
+    }
+
+    pub(crate) fn with_cause(mut self, cause: impl Into<Box<dyn StdError>>) -> Self {
+        self.inner.cause = Some(cause.into());
+        self
     }
 }
 
-/// Errors that can generate responses.
-pub trait ResponseError: fmt::Debug + fmt::Display {
-    /// Returns appropriate status code for error.
-    ///
-    /// A 500 Internal Server Error is used by default. If [error_response](Self::error_response) is
-    /// also implemented and does not call `self.status_code()`, then this will not be used.
-    fn status_code(&self) -> StatusCode {
-        StatusCode::INTERNAL_SERVER_ERROR
-    }
+impl From<Error> for Response<AnyBody> {
+    fn from(err: Error) -> Self {
+        let status_code = match err.inner.kind {
+            Kind::Parse => StatusCode::BAD_REQUEST,
+            _ => StatusCode::INTERNAL_SERVER_ERROR,
+        };
 
-    /// Creates full response for error.
-    ///
-    /// By default, the generated response uses a 500 Internal Server Error status code, a
-    /// `Content-Type` of `text/plain`, and the body is set to `Self`'s `Display` impl.
-    fn error_response(&self) -> Response<Body> {
-        let mut resp = Response::new(self.status_code());
-        let mut buf = BytesMut::new();
-        let _ = write!(Writer(&mut buf), "{}", self);
-        resp.headers_mut().insert(
-            header::CONTENT_TYPE,
-            header::HeaderValue::from_static("text/plain; charset=utf-8"),
-        );
-        resp.set_body(Body::from(buf))
+        Response::new(status_code).set_body(Body::from(err.to_string()))
     }
-
-    downcast_get_type_id!();
 }
 
-downcast!(ResponseError);
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Display)]
+pub enum Kind {
+    #[display(fmt = "error processing HTTP")]
+    Http,
 
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Display::fmt(&self.cause, f)
-    }
+    #[display(fmt = "error parsing HTTP message")]
+    Parse,
+
+    #[display(fmt = "request payload read error")]
+    Payload,
+
+    #[display(fmt = "response body write error")]
+    Body,
+
+    #[display(fmt = "send response error")]
+    SendResponse,
+
+    #[display(fmt = "error in WebSocket process")]
+    Ws,
+
+    #[display(fmt = "connection error")]
+    Io,
+
+    #[display(fmt = "encoder error")]
+    Encoder,
 }
 
 impl fmt::Debug for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "{:?}", &self.cause)
+        // TODO: more detail
+        f.write_str("actix_http::Error")
     }
 }
 
-impl std::error::Error for Error {
-    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
-        None
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.inner.cause.as_ref() {
+            Some(err) => write!(f, "{}: {}", &self.inner.kind, err),
+            None => write!(f, "{}", &self.inner.kind),
+        }
     }
 }
 
-impl From<()> for Error {
-    fn from(_: ()) -> Self {
-        Error::from(UnitError)
+impl StdError for Error {
+    fn source(&self) -> Option<&(dyn StdError + 'static)> {
+        self.inner.cause.as_ref().map(Box::as_ref)
     }
 }
 
 impl From<std::convert::Infallible> for Error {
-    fn from(_: std::convert::Infallible) -> Self {
-        // hint that an error that will never happen
-        unreachable!()
+    fn from(err: std::convert::Infallible) -> Self {
+        match err {}
     }
 }
 
-/// Convert `Error` to a `Response` instance
-impl From<Error> for Response<Body> {
-    fn from(err: Error) -> Self {
-        Response::from_error(err)
+impl From<ws::ProtocolError> for Error {
+    fn from(err: ws::ProtocolError) -> Self {
+        Self::new_ws().with_cause(err)
     }
 }
 
-/// `Error` for any error that implements `ResponseError`
-impl<T: ResponseError + 'static> From<T> for Error {
-    fn from(err: T) -> Error {
-        Error {
-            cause: Box::new(err),
-        }
+impl From<HttpError> for Error {
+    fn from(err: HttpError) -> Self {
+        Self::new_http().with_cause(err)
     }
 }
 
-#[derive(Debug, Display, Error)]
-#[display(fmt = "Unknown Error")]
-struct UnitError;
-
-impl ResponseError for Box<dyn StdError + 'static> {}
-
-/// Returns [`StatusCode::INTERNAL_SERVER_ERROR`] for [`UnitError`].
-impl ResponseError for UnitError {}
-
-/// Returns [`StatusCode::INTERNAL_SERVER_ERROR`] for [`actix_tls::accept::openssl::SslError`].
-#[cfg(feature = "openssl")]
-impl ResponseError for actix_tls::accept::openssl::SslError {}
-
-/// Returns [`StatusCode::BAD_REQUEST`] for [`DeError`].
-impl ResponseError for DeError {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
-    }
-}
-
-/// Returns [`StatusCode::BAD_REQUEST`] for [`Utf8Error`].
-impl ResponseError for Utf8Error {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
-    }
-}
-
-/// Returns [`StatusCode::INTERNAL_SERVER_ERROR`] for [`HttpError`].
-impl ResponseError for HttpError {}
-
-/// Inspects the underlying [`io::ErrorKind`] and returns an appropriate status code.
-///
-/// If the error is [`io::ErrorKind::NotFound`], [`StatusCode::NOT_FOUND`] is returned. If the
-/// error is [`io::ErrorKind::PermissionDenied`], [`StatusCode::FORBIDDEN`] is returned. Otherwise,
-/// [`StatusCode::INTERNAL_SERVER_ERROR`] is returned.
-impl ResponseError for io::Error {
-    fn status_code(&self) -> StatusCode {
-        match self.kind() {
-            io::ErrorKind::NotFound => StatusCode::NOT_FOUND,
-            io::ErrorKind::PermissionDenied => StatusCode::FORBIDDEN,
-            _ => StatusCode::INTERNAL_SERVER_ERROR,
-        }
-    }
-}
-
-/// Returns [`StatusCode::BAD_REQUEST`] for [`header::InvalidHeaderValue`].
-impl ResponseError for header::InvalidHeaderValue {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
+impl From<ws::HandshakeError> for Error {
+    fn from(err: ws::HandshakeError) -> Self {
+        Self::new_ws().with_cause(err)
     }
 }
 
@@ -218,13 +199,6 @@ pub enum ParseError {
     Utf8(Utf8Error),
 }
 
-/// Return `BadRequest` for `ParseError`
-impl ResponseError for ParseError {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
-    }
-}
-
 impl From<io::Error> for ParseError {
     fn from(err: io::Error) -> ParseError {
         ParseError::Io(err)
@@ -263,14 +237,23 @@ impl From<httparse::Error> for ParseError {
     }
 }
 
+impl From<ParseError> for Error {
+    fn from(err: ParseError) -> Self {
+        Self::new_parse().with_cause(err)
+    }
+}
+
+impl From<ParseError> for Response<AnyBody> {
+    fn from(err: ParseError) -> Self {
+        Error::from(err).into()
+    }
+}
+
 /// A set of errors that can occur running blocking tasks in thread pool.
 #[derive(Debug, Display, Error)]
 #[display(fmt = "Blocking thread pool is gone")]
 pub struct BlockingError;
 
-/// `InternalServerError` for `BlockingError`
-impl ResponseError for BlockingError {}
-
 /// A set of errors that can occur during payload parsing.
 #[derive(Debug, Display)]
 #[non_exhaustive]
@@ -344,16 +327,9 @@ impl From<BlockingError> for PayloadError {
     }
 }
 
-/// `PayloadError` returns two possible results:
-///
-/// - `Overflow` returns `PayloadTooLarge`
-/// - Other errors returns `BadRequest`
-impl ResponseError for PayloadError {
-    fn status_code(&self) -> StatusCode {
-        match *self {
-            PayloadError::Overflow => StatusCode::PAYLOAD_TOO_LARGE,
-            _ => StatusCode::BAD_REQUEST,
-        }
+impl From<PayloadError> for Error {
+    fn from(err: PayloadError) -> Self {
+        Self::new_payload().with_cause(err)
     }
 }
 
@@ -362,13 +338,19 @@ impl ResponseError for PayloadError {
 #[non_exhaustive]
 pub enum DispatchError {
     /// Service error
-    Service(Error),
+    // FIXME: display and error type
+    #[display(fmt = "Service Error")]
+    Service(#[error(not(source))] Response<AnyBody>),
+
+    /// Body error
+    // FIXME: display and error type
+    #[display(fmt = "Body Error")]
+    Body(#[error(not(source))] Box<dyn StdError>),
 
     /// Upgrade service error
     Upgrade,
 
-    /// An `io::Error` that occurred while trying to read or write to a network
-    /// stream.
+    /// An `io::Error` that occurred while trying to read or write to a network stream.
     #[display(fmt = "IO error: {}", _0)]
     Io(io::Error),
 
@@ -434,12 +416,6 @@ mod content_type_test_impls {
     }
 }
 
-impl ResponseError for ContentTypeError {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -448,42 +424,36 @@ mod tests {
 
     #[test]
     fn test_into_response() {
-        let resp: Response<Body> = ParseError::Incomplete.error_response();
+        let resp: Response<AnyBody> = ParseError::Incomplete.into();
         assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
 
         let err: HttpError = StatusCode::from_u16(10000).err().unwrap().into();
-        let resp: Response<Body> = err.error_response();
+        let resp: Response<AnyBody> = Error::new_http().with_cause(err).into();
         assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
     }
 
     #[test]
     fn test_as_response() {
         let orig = io::Error::new(io::ErrorKind::Other, "other");
-        let e: Error = ParseError::Io(orig).into();
-        assert_eq!(format!("{}", e.as_response_error()), "IO error: other");
-    }
-
-    #[test]
-    fn test_error_cause() {
-        let orig = io::Error::new(io::ErrorKind::Other, "other");
-        let desc = orig.to_string();
-        let e = Error::from(orig);
-        assert_eq!(format!("{}", e.as_response_error()), desc);
+        let err: Error = ParseError::Io(orig).into();
+        assert_eq!(
+            format!("{}", err),
+            "error parsing HTTP message: IO error: other"
+        );
     }
 
     #[test]
     fn test_error_display() {
         let orig = io::Error::new(io::ErrorKind::Other, "other");
-        let desc = orig.to_string();
-        let e = Error::from(orig);
-        assert_eq!(format!("{}", e), desc);
+        let err = Error::new_io().with_cause(orig);
+        assert_eq!("connection error: other", err.to_string());
     }
 
     #[test]
     fn test_error_http_response() {
         let orig = io::Error::new(io::ErrorKind::Other, "other");
-        let e = Error::from(orig);
-        let resp: Response<Body> = e.into();
+        let err = Error::new_io().with_cause(orig);
+        let resp: Response<AnyBody> = err.into();
         assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
     }
 
@@ -535,14 +505,4 @@ mod tests {
         from!(httparse::Error::TooManyHeaders => ParseError::TooLarge);
         from!(httparse::Error::Version => ParseError::Version);
     }
-
-    #[test]
-    fn test_error_casting() {
-        let err = PayloadError::Overflow;
-        let resp_err: &dyn ResponseError = &err;
-        let err = resp_err.downcast_ref::<PayloadError>().unwrap();
-        assert_eq!(err.to_string(), "Payload reached size limit.");
-        let not_err = resp_err.downcast_ref::<ContentTypeError>();
-        assert!(not_err.is_none());
-    }
 }
diff --git a/actix-http/src/h1/decoder.rs b/actix-http/src/h1/decoder.rs
index 8aba9f623..f240710c2 100644
--- a/actix-http/src/h1/decoder.rs
+++ b/actix-http/src/h1/decoder.rs
@@ -102,7 +102,7 @@ pub(crate) trait MessageType: Sized {
                     }
                     // transfer-encoding
                     header::TRANSFER_ENCODING => {
-                        if let Ok(s) = value.to_str().map(|s| s.trim()) {
+                        if let Ok(s) = value.to_str().map(str::trim) {
                             chunked = s.eq_ignore_ascii_case("chunked");
                         } else {
                             return Err(ParseError::Header);
@@ -110,7 +110,7 @@ pub(crate) trait MessageType: Sized {
                     }
                     // connection keep-alive state
                     header::CONNECTION => {
-                        ka = if let Ok(conn) = value.to_str().map(|conn| conn.trim()) {
+                        ka = if let Ok(conn) = value.to_str().map(str::trim) {
                             if conn.eq_ignore_ascii_case("keep-alive") {
                                 Some(ConnectionType::KeepAlive)
                             } else if conn.eq_ignore_ascii_case("close") {
@@ -125,7 +125,7 @@ pub(crate) trait MessageType: Sized {
                         };
                     }
                     header::UPGRADE => {
-                        if let Ok(val) = value.to_str().map(|val| val.trim()) {
+                        if let Ok(val) = value.to_str().map(str::trim) {
                             if val.eq_ignore_ascii_case("websocket") {
                                 has_upgrade_websocket = true;
                             }
diff --git a/actix-http/src/h1/dispatcher.rs b/actix-http/src/h1/dispatcher.rs
index c81d0b3bc..deb25763c 100644
--- a/actix-http/src/h1/dispatcher.rs
+++ b/actix-http/src/h1/dispatcher.rs
@@ -1,5 +1,6 @@
 use std::{
     collections::VecDeque,
+    error::Error as StdError,
     fmt,
     future::Future,
     io, mem, net,
@@ -17,19 +18,19 @@ use futures_core::ready;
 use log::{error, trace};
 use pin_project::pin_project;
 
-use crate::body::{Body, BodySize, MessageBody};
-use crate::config::ServiceConfig;
-use crate::error::{DispatchError, Error};
-use crate::error::{ParseError, PayloadError};
-use crate::http::StatusCode;
-use crate::request::Request;
-use crate::response::Response;
-use crate::service::HttpFlow;
-use crate::OnConnectData;
+use crate::{
+    body::{AnyBody, BodySize, MessageBody},
+    config::ServiceConfig,
+    error::{DispatchError, ParseError, PayloadError},
+    service::HttpFlow,
+    OnConnectData, Request, Response, StatusCode,
+};
 
-use super::codec::Codec;
-use super::payload::{Payload, PayloadSender, PayloadStatus};
-use super::{Message, MessageType};
+use super::{
+    codec::Codec,
+    payload::{Payload, PayloadSender, PayloadStatus},
+    Message, MessageType,
+};
 
 const LW_BUFFER_SIZE: usize = 1024;
 const HW_BUFFER_SIZE: usize = 1024 * 8;
@@ -50,13 +51,13 @@ bitflags! {
 pub struct Dispatcher<T, S, B, X, U>
 where
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -72,13 +73,13 @@ where
 enum DispatcherState<T, S, B, X, U>
 where
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -91,13 +92,13 @@ where
 struct InnerDispatcher<T, S, B, X, U>
 where
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -136,13 +137,13 @@ where
     X: Service<Request, Response = Request>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     None,
     ExpectCall(#[pin] X::Future),
     ServiceCall(#[pin] S::Future),
     SendPayload(#[pin] B),
-    SendErrorPayload(#[pin] Body),
+    SendErrorPayload(#[pin] AnyBody),
 }
 
 impl<S, B, X> State<S, B, X>
@@ -152,7 +153,7 @@ where
     X: Service<Request, Response = Request>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     fn is_empty(&self) -> bool {
         matches!(self, State::None)
@@ -170,14 +171,14 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -231,14 +232,14 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -334,7 +335,7 @@ where
     fn send_error_response(
         mut self: Pin<&mut Self>,
         message: Response<()>,
-        body: Body,
+        body: AnyBody,
     ) -> Result<(), DispatchError> {
         let size = self.as_mut().send_response_inner(message, &body)?;
         let state = match size {
@@ -379,7 +380,7 @@ where
                         // send_response would update InnerDispatcher state to SendPayload or
                         // None(If response body is empty).
                         // continue loop to poll it.
-                        self.as_mut().send_error_response(res, Body::Empty)?;
+                        self.as_mut().send_error_response(res, AnyBody::Empty)?;
                     }
 
                     // return with upgrade request and poll it exclusively.
@@ -399,7 +400,7 @@ where
 
                     // send service call error as response
                     Poll::Ready(Err(err)) => {
-                        let res = Response::from_error(err);
+                        let res: Response<AnyBody> = err.into();
                         let (res, body) = res.replace_body(());
                         self.as_mut().send_error_response(res, body)?;
                     }
@@ -438,7 +439,7 @@ where
                             }
 
                             Poll::Ready(Some(Err(err))) => {
-                                return Err(DispatchError::Service(err.into()))
+                                return Err(DispatchError::Body(err.into()))
                             }
 
                             Poll::Pending => return Ok(PollResponse::DoNothing),
@@ -473,7 +474,7 @@ where
                             }
 
                             Poll::Ready(Some(Err(err))) => {
-                                return Err(DispatchError::Service(err))
+                                return Err(DispatchError::Service(err.into()))
                             }
 
                             Poll::Pending => return Ok(PollResponse::DoNothing),
@@ -496,7 +497,7 @@ where
 
                     // send expect error as response
                     Poll::Ready(Err(err)) => {
-                        let res = Response::from_error(err);
+                        let res: Response<AnyBody> = err.into();
                         let (res, body) = res.replace_body(());
                         self.as_mut().send_error_response(res, body)?;
                     }
@@ -514,14 +515,13 @@ where
         cx: &mut Context<'_>,
     ) -> Result<(), DispatchError> {
         // Handle `EXPECT: 100-Continue` header
+        let mut this = self.as_mut().project();
         if req.head().expect() {
             // set dispatcher state so the future is pinned.
-            let mut this = self.as_mut().project();
             let task = this.flow.expect.call(req);
             this.state.set(State::ExpectCall(task));
         } else {
             // the same as above.
-            let mut this = self.as_mut().project();
             let task = this.flow.service.call(req);
             this.state.set(State::ServiceCall(task));
         };
@@ -546,7 +546,7 @@ where
                         // to notify the dispatcher a new state is set and the outer loop
                         // should be continue.
                         Poll::Ready(Err(err)) => {
-                            let res = Response::from_error(err);
+                            let res: Response<AnyBody> = err.into();
                             let (res, body) = res.replace_body(());
                             return self.send_error_response(res, body);
                         }
@@ -566,7 +566,7 @@ where
                         Poll::Pending => Ok(()),
                         // see the comment on ExpectCall state branch's Ready(Err(err)).
                         Poll::Ready(Err(err)) => {
-                            let res = Response::from_error(err);
+                            let res: Response<AnyBody> = err.into();
                             let (res, body) = res.replace_body(());
                             self.send_error_response(res, body)
                         }
@@ -772,7 +772,7 @@ where
                                 trace!("Slow request timeout");
                                 let _ = self.as_mut().send_error_response(
                                     Response::with_body(StatusCode::REQUEST_TIMEOUT, ()),
-                                    Body::Empty,
+                                    AnyBody::Empty,
                                 );
                                 this = self.project();
                                 this.flags.insert(Flags::STARTED | Flags::SHUTDOWN);
@@ -909,14 +909,14 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -1067,16 +1067,17 @@ mod tests {
         }
     }
 
-    fn ok_service() -> impl Service<Request, Response = Response<Body>, Error = Error> {
+    fn ok_service() -> impl Service<Request, Response = Response<AnyBody>, Error = Error>
+    {
         fn_service(|_req: Request| ready(Ok::<_, Error>(Response::ok())))
     }
 
     fn echo_path_service(
-    ) -> impl Service<Request, Response = Response<Body>, Error = Error> {
+    ) -> impl Service<Request, Response = Response<AnyBody>, Error = Error> {
         fn_service(|req: Request| {
             let path = req.path().as_bytes();
             ready(Ok::<_, Error>(
-                Response::ok().set_body(Body::from_slice(path)),
+                Response::ok().set_body(AnyBody::from_slice(path)),
             ))
         })
     }
diff --git a/actix-http/src/h1/encoder.rs b/actix-http/src/h1/encoder.rs
index eaabcb687..254981123 100644
--- a/actix-http/src/h1/encoder.rs
+++ b/actix-http/src/h1/encoder.rs
@@ -6,14 +6,15 @@ use std::{cmp, io};
 
 use bytes::{BufMut, BytesMut};
 
-use crate::body::BodySize;
-use crate::config::ServiceConfig;
-use crate::header::{map::Value, HeaderName};
-use crate::helpers;
-use crate::http::header::{CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCODING};
-use crate::http::{HeaderMap, StatusCode, Version};
-use crate::message::{ConnectionType, RequestHeadType};
-use crate::response::Response;
+use crate::{
+    body::BodySize,
+    config::ServiceConfig,
+    header::{map::Value, HeaderMap, HeaderName},
+    header::{CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCODING},
+    helpers,
+    message::{ConnectionType, RequestHeadType},
+    Response, StatusCode, Version,
+};
 
 const AVERAGE_HEADER_SIZE: usize = 30;
 
@@ -287,7 +288,7 @@ impl MessageType for RequestHeadType {
         let head = self.as_ref();
         dst.reserve(256 + head.headers.len() * AVERAGE_HEADER_SIZE);
         write!(
-            helpers::Writer(dst),
+            helpers::MutWriter(dst),
             "{} {} {}",
             head.method,
             head.uri.path_and_query().map(|u| u.as_str()).unwrap_or("/"),
@@ -420,7 +421,7 @@ impl TransferEncoding {
                     *eof = true;
                     buf.extend_from_slice(b"0\r\n\r\n");
                 } else {
-                    writeln!(helpers::Writer(buf), "{:X}\r", msg.len())
+                    writeln!(helpers::MutWriter(buf), "{:X}\r", msg.len())
                         .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
 
                     buf.reserve(msg.len() + 2);
diff --git a/actix-http/src/h1/payload.rs b/actix-http/src/h1/payload.rs
index e72493fa2..cc771f28a 100644
--- a/actix-http/src/h1/payload.rs
+++ b/actix-http/src/h1/payload.rs
@@ -186,8 +186,7 @@ impl Inner {
         if self
             .task
             .as_ref()
-            .map(|w| !cx.waker().will_wake(w))
-            .unwrap_or(true)
+            .map_or(true, |w| !cx.waker().will_wake(w))
         {
             self.task = Some(cx.waker().clone());
         }
@@ -199,8 +198,7 @@ impl Inner {
         if self
             .io_task
             .as_ref()
-            .map(|w| !cx.waker().will_wake(w))
-            .unwrap_or(true)
+            .map_or(true, |w| !cx.waker().will_wake(w))
         {
             self.io_task = Some(cx.waker().clone());
         }
diff --git a/actix-http/src/h1/service.rs b/actix-http/src/h1/service.rs
index 1ab85cbf3..dbad8cfac 100644
--- a/actix-http/src/h1/service.rs
+++ b/actix-http/src/h1/service.rs
@@ -1,7 +1,11 @@
-use std::marker::PhantomData;
-use std::rc::Rc;
-use std::task::{Context, Poll};
-use std::{fmt, net};
+use std::{
+    error::Error as StdError,
+    fmt,
+    marker::PhantomData,
+    net,
+    rc::Rc,
+    task::{Context, Poll},
+};
 
 use actix_codec::{AsyncRead, AsyncWrite, Framed};
 use actix_rt::net::TcpStream;
@@ -11,17 +15,15 @@ use actix_service::{
 use actix_utils::future::ready;
 use futures_core::future::LocalBoxFuture;
 
-use crate::body::MessageBody;
-use crate::config::ServiceConfig;
-use crate::error::{DispatchError, Error};
-use crate::request::Request;
-use crate::response::Response;
-use crate::service::HttpServiceHandler;
-use crate::{ConnectCallback, OnConnectData};
+use crate::{
+    body::{AnyBody, MessageBody},
+    config::ServiceConfig,
+    error::DispatchError,
+    service::HttpServiceHandler,
+    ConnectCallback, OnConnectData, Request, Response,
+};
 
-use super::codec::Codec;
-use super::dispatcher::Dispatcher;
-use super::{ExpectHandler, UpgradeHandler};
+use super::{codec::Codec, dispatcher::Dispatcher, ExpectHandler, UpgradeHandler};
 
 /// `ServiceFactory` implementation for HTTP1 transport
 pub struct H1Service<T, S, B, X = ExpectHandler, U = UpgradeHandler> {
@@ -36,7 +38,7 @@ pub struct H1Service<T, S, B, X = ExpectHandler, U = UpgradeHandler> {
 impl<T, S, B> H1Service<T, S, B>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>>,
     B: MessageBody,
@@ -61,21 +63,21 @@ impl<S, B, X, U> H1Service<TcpStream, S, B, X, U>
 where
     S: ServiceFactory<Request, Config = ()>,
     S::Future: 'static,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: ServiceFactory<Request, Config = (), Response = Request>,
     X::Future: 'static,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
     X::InitError: fmt::Debug,
 
     U: ServiceFactory<(Request, Framed<TcpStream, Codec>), Config = (), Response = ()>,
     U::Future: 'static,
-    U::Error: fmt::Display + Into<Error>,
+    U::Error: fmt::Display + Into<Response<AnyBody>>,
     U::InitError: fmt::Debug,
 {
     /// Create simple tcp stream service
@@ -110,16 +112,16 @@ mod openssl {
     where
         S: ServiceFactory<Request, Config = ()>,
         S::Future: 'static,
-        S::Error: Into<Error>,
+        S::Error: Into<Response<AnyBody>>,
         S::InitError: fmt::Debug,
         S::Response: Into<Response<B>>,
 
         B: MessageBody,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
 
         X: ServiceFactory<Request, Config = (), Response = Request>,
         X::Future: 'static,
-        X::Error: Into<Error>,
+        X::Error: Into<Response<AnyBody>>,
         X::InitError: fmt::Debug,
 
         U: ServiceFactory<
@@ -128,7 +130,7 @@ mod openssl {
             Response = (),
         >,
         U::Future: 'static,
-        U::Error: fmt::Display + Into<Error>,
+        U::Error: fmt::Display + Into<Response<AnyBody>>,
         U::InitError: fmt::Debug,
     {
         /// Create openssl based service
@@ -170,16 +172,16 @@ mod rustls {
     where
         S: ServiceFactory<Request, Config = ()>,
         S::Future: 'static,
-        S::Error: Into<Error>,
+        S::Error: Into<Response<AnyBody>>,
         S::InitError: fmt::Debug,
         S::Response: Into<Response<B>>,
 
         B: MessageBody,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
 
         X: ServiceFactory<Request, Config = (), Response = Request>,
         X::Future: 'static,
-        X::Error: Into<Error>,
+        X::Error: Into<Response<AnyBody>>,
         X::InitError: fmt::Debug,
 
         U: ServiceFactory<
@@ -188,7 +190,7 @@ mod rustls {
             Response = (),
         >,
         U::Future: 'static,
-        U::Error: fmt::Display + Into<Error>,
+        U::Error: fmt::Display + Into<Response<AnyBody>>,
         U::InitError: fmt::Debug,
     {
         /// Create rustls based service
@@ -217,7 +219,7 @@ mod rustls {
 impl<T, S, B, X, U> H1Service<T, S, B, X, U>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::Response: Into<Response<B>>,
     S::InitError: fmt::Debug,
     B: MessageBody,
@@ -225,7 +227,7 @@ where
     pub fn expect<X1>(self, expect: X1) -> H1Service<T, S, B, X1, U>
     where
         X1: ServiceFactory<Request, Response = Request>,
-        X1::Error: Into<Error>,
+        X1::Error: Into<Response<AnyBody>>,
         X1::InitError: fmt::Debug,
     {
         H1Service {
@@ -268,21 +270,21 @@ where
 
     S: ServiceFactory<Request, Config = ()>,
     S::Future: 'static,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::Response: Into<Response<B>>,
     S::InitError: fmt::Debug,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: ServiceFactory<Request, Config = (), Response = Request>,
     X::Future: 'static,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
     X::InitError: fmt::Debug,
 
     U: ServiceFactory<(Request, Framed<T, Codec>), Config = (), Response = ()>,
     U::Future: 'static,
-    U::Error: fmt::Display + Into<Error>,
+    U::Error: fmt::Display + Into<Response<AnyBody>>,
     U::InitError: fmt::Debug,
 {
     type Response = ();
@@ -338,17 +340,17 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, Codec>), Response = ()>,
-    U::Error: fmt::Display + Into<Error>,
+    U::Error: fmt::Display + Into<Response<AnyBody>>,
 {
     type Response = ();
     type Error = DispatchError;
diff --git a/actix-http/src/h1/utils.rs b/actix-http/src/h1/utils.rs
index 90e44daa4..523e652fd 100644
--- a/actix-http/src/h1/utils.rs
+++ b/actix-http/src/h1/utils.rs
@@ -81,7 +81,9 @@ where
                                 let _ = this.body.take();
                             }
                             let framed = this.framed.as_mut().as_pin_mut().unwrap();
-                            framed.write(Message::Chunk(item))?;
+                            framed.write(Message::Chunk(item)).map_err(|err| {
+                                Error::new_send_response().with_cause(err)
+                            })?;
                         }
                         Poll::Pending => body_ready = false,
                     }
@@ -92,7 +94,10 @@ where
 
             // flush write buffer
             if !framed.is_write_buf_empty() {
-                match framed.flush(cx)? {
+                match framed
+                    .flush(cx)
+                    .map_err(|err| Error::new_send_response().with_cause(err))?
+                {
                     Poll::Ready(_) => {
                         if body_ready {
                             continue;
@@ -106,7 +111,9 @@ where
 
             // send response
             if let Some(res) = this.res.take() {
-                framed.write(res)?;
+                framed
+                    .write(res)
+                    .map_err(|err| Error::new_send_response().with_cause(err))?;
                 continue;
             }
 
diff --git a/actix-http/src/h2/dispatcher.rs b/actix-http/src/h2/dispatcher.rs
index baff20e51..ea149b1e0 100644
--- a/actix-http/src/h2/dispatcher.rs
+++ b/actix-http/src/h2/dispatcher.rs
@@ -1,5 +1,6 @@
 use std::{
     cmp,
+    error::Error as StdError,
     future::Future,
     marker::PhantomData,
     net,
@@ -18,15 +19,12 @@ use http::header::{HeaderValue, CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCOD
 use log::{error, trace};
 use pin_project_lite::pin_project;
 
-use crate::body::{BodySize, MessageBody};
-use crate::config::ServiceConfig;
-use crate::error::Error;
-use crate::message::ResponseHead;
-use crate::payload::Payload;
-use crate::request::Request;
-use crate::response::Response;
-use crate::service::HttpFlow;
-use crate::OnConnectData;
+use crate::{
+    body::{AnyBody, BodySize, MessageBody},
+    config::ServiceConfig,
+    service::HttpFlow,
+    OnConnectData, Payload, Request, Response, ResponseHead,
+};
 
 const CHUNK_SIZE: usize = 16_384;
 
@@ -66,12 +64,12 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     S::Future: 'static,
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     type Output = Result<(), crate::error::DispatchError>;
 
@@ -106,7 +104,7 @@ where
                 let res = match fut.await {
                     Ok(res) => handle_response(res.into(), tx, config).await,
                     Err(err) => {
-                        let res = Response::from_error(err.into());
+                        let res: Response<AnyBody> = err.into();
                         handle_response(res, tx, config).await
                     }
                 };
@@ -133,7 +131,7 @@ where
 enum DispatchError {
     SendResponse(h2::Error),
     SendData(h2::Error),
-    ResponseBody(Error),
+    ResponseBody(Box<dyn StdError>),
 }
 
 async fn handle_response<B>(
@@ -143,7 +141,7 @@ async fn handle_response<B>(
 ) -> Result<(), DispatchError>
 where
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     let (res, body) = res.replace_body(());
 
diff --git a/actix-http/src/h2/service.rs b/actix-http/src/h2/service.rs
index a75abef7d..09e24045b 100644
--- a/actix-http/src/h2/service.rs
+++ b/actix-http/src/h2/service.rs
@@ -1,8 +1,12 @@
-use std::future::Future;
-use std::marker::PhantomData;
-use std::pin::Pin;
-use std::task::{Context, Poll};
-use std::{net, rc::Rc};
+use std::{
+    error::Error as StdError,
+    future::Future,
+    marker::PhantomData,
+    net,
+    pin::Pin,
+    rc::Rc,
+    task::{Context, Poll},
+};
 
 use actix_codec::{AsyncRead, AsyncWrite};
 use actix_rt::net::TcpStream;
@@ -13,16 +17,16 @@ use actix_service::{
 use actix_utils::future::ready;
 use bytes::Bytes;
 use futures_core::{future::LocalBoxFuture, ready};
-use h2::server::{handshake, Handshake};
+use h2::server::{handshake as h2_handshake, Handshake as H2Handshake};
 use log::error;
 
-use crate::body::MessageBody;
-use crate::config::ServiceConfig;
-use crate::error::{DispatchError, Error};
-use crate::request::Request;
-use crate::response::Response;
-use crate::service::HttpFlow;
-use crate::{ConnectCallback, OnConnectData};
+use crate::{
+    body::{AnyBody, MessageBody},
+    config::ServiceConfig,
+    error::DispatchError,
+    service::HttpFlow,
+    ConnectCallback, OnConnectData, Request, Response,
+};
 
 use super::dispatcher::Dispatcher;
 
@@ -37,12 +41,12 @@ pub struct H2Service<T, S, B> {
 impl<T, S, B> H2Service<T, S, B>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
 
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     /// Create new `H2Service` instance with config.
     pub(crate) fn with_config<F: IntoServiceFactory<S, Request>>(
@@ -68,12 +72,12 @@ impl<S, B> H2Service<TcpStream, S, B>
 where
     S: ServiceFactory<Request, Config = ()>,
     S::Future: 'static,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
 
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     /// Create plain TCP based service
     pub fn tcp(
@@ -107,12 +111,12 @@ mod openssl {
     where
         S: ServiceFactory<Request, Config = ()>,
         S::Future: 'static,
-        S::Error: Into<Error> + 'static,
+        S::Error: Into<Response<AnyBody>> + 'static,
         S::Response: Into<Response<B>> + 'static,
         <S::Service as Service<Request>>::Future: 'static,
 
         B: MessageBody + 'static,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
     {
         /// Create OpenSSL based service
         pub fn openssl(
@@ -153,12 +157,12 @@ mod rustls {
     where
         S: ServiceFactory<Request, Config = ()>,
         S::Future: 'static,
-        S::Error: Into<Error> + 'static,
+        S::Error: Into<Response<AnyBody>> + 'static,
         S::Response: Into<Response<B>> + 'static,
         <S::Service as Service<Request>>::Future: 'static,
 
         B: MessageBody + 'static,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
     {
         /// Create Rustls based service
         pub fn rustls(
@@ -171,7 +175,8 @@ mod rustls {
             Error = TlsError<io::Error, DispatchError>,
             InitError = S::InitError,
         > {
-            let protos = vec!["h2".to_string().into()];
+            let mut protos = vec![b"h2".to_vec()];
+            protos.extend_from_slice(&config.alpn_protocols);
             config.set_protocols(&protos);
 
             Acceptor::new(config)
@@ -196,12 +201,12 @@ where
 
     S: ServiceFactory<Request, Config = ()>,
     S::Future: 'static,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
 
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     type Response = ();
     type Error = DispatchError;
@@ -236,7 +241,7 @@ where
 impl<T, S, B> H2ServiceHandler<T, S, B>
 where
     S: Service<Request>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
     B: MessageBody + 'static,
@@ -259,11 +264,11 @@ impl<T, S, B> Service<(T, Option<net::SocketAddr>)> for H2ServiceHandler<T, S, B
 where
     T: AsyncRead + AsyncWrite + Unpin,
     S: Service<Request>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     type Response = ();
     type Error = DispatchError;
@@ -287,7 +292,7 @@ where
                 Some(self.cfg.clone()),
                 addr,
                 on_connect_data,
-                handshake(io),
+                h2_handshake(io),
             ),
         }
     }
@@ -304,7 +309,7 @@ where
         Option<ServiceConfig>,
         Option<net::SocketAddr>,
         OnConnectData,
-        Handshake<T, Bytes>,
+        H2Handshake<T, Bytes>,
     ),
 }
 
@@ -312,7 +317,7 @@ pub struct H2ServiceHandlerResponse<T, S, B>
 where
     T: AsyncRead + AsyncWrite + Unpin,
     S: Service<Request>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
     B: MessageBody + 'static,
@@ -324,11 +329,11 @@ impl<T, S, B> Future for H2ServiceHandlerResponse<T, S, B>
 where
     T: AsyncRead + AsyncWrite + Unpin,
     S: Service<Request>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     type Output = Result<(), DispatchError>;
 
diff --git a/actix-http/src/header/as_name.rs b/actix-http/src/header/as_name.rs
index af81ff7f2..5ce321566 100644
--- a/actix-http/src/header/as_name.rs
+++ b/actix-http/src/header/as_name.rs
@@ -8,40 +8,42 @@ use http::header::{HeaderName, InvalidHeaderName};
 
 pub trait AsHeaderName: Sealed {}
 
+pub struct Seal;
+
 pub trait Sealed {
-    fn try_as_name(&self) -> Result<Cow<'_, HeaderName>, InvalidHeaderName>;
+    fn try_as_name(&self, seal: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName>;
 }
 
 impl Sealed for HeaderName {
-    fn try_as_name(&self) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
+    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
         Ok(Cow::Borrowed(self))
     }
 }
 impl AsHeaderName for HeaderName {}
 
 impl Sealed for &HeaderName {
-    fn try_as_name(&self) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
+    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
         Ok(Cow::Borrowed(*self))
     }
 }
 impl AsHeaderName for &HeaderName {}
 
 impl Sealed for &str {
-    fn try_as_name(&self) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
+    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
         HeaderName::from_str(self).map(Cow::Owned)
     }
 }
 impl AsHeaderName for &str {}
 
 impl Sealed for String {
-    fn try_as_name(&self) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
+    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
         HeaderName::from_str(self).map(Cow::Owned)
     }
 }
 impl AsHeaderName for String {}
 
 impl Sealed for &String {
-    fn try_as_name(&self) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
+    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
         HeaderName::from_str(self).map(Cow::Owned)
     }
 }
diff --git a/actix-http/src/header/map.rs b/actix-http/src/header/map.rs
index 106e44edb..634d9282f 100644
--- a/actix-http/src/header/map.rs
+++ b/actix-http/src/header/map.rs
@@ -213,7 +213,7 @@ impl HeaderMap {
     }
 
     fn get_value(&self, key: impl AsHeaderName) -> Option<&Value> {
-        match key.try_as_name().ok()? {
+        match key.try_as_name(super::as_name::Seal).ok()? {
             Cow::Borrowed(name) => self.inner.get(name),
             Cow::Owned(name) => self.inner.get(&name),
         }
@@ -249,7 +249,7 @@ impl HeaderMap {
     /// assert!(map.get("INVALID HEADER NAME").is_none());
     /// ```
     pub fn get(&self, key: impl AsHeaderName) -> Option<&HeaderValue> {
-        self.get_value(key).map(|val| val.first())
+        self.get_value(key).map(Value::first)
     }
 
     /// Returns a mutable reference to the _first_ value associated a header name.
@@ -279,9 +279,9 @@ impl HeaderMap {
     /// assert!(map.get("INVALID HEADER NAME").is_none());
     /// ```
     pub fn get_mut(&mut self, key: impl AsHeaderName) -> Option<&mut HeaderValue> {
-        match key.try_as_name().ok()? {
-            Cow::Borrowed(name) => self.inner.get_mut(name).map(|v| v.first_mut()),
-            Cow::Owned(name) => self.inner.get_mut(&name).map(|v| v.first_mut()),
+        match key.try_as_name(super::as_name::Seal).ok()? {
+            Cow::Borrowed(name) => self.inner.get_mut(name).map(Value::first_mut),
+            Cow::Owned(name) => self.inner.get_mut(&name).map(Value::first_mut),
         }
     }
 
@@ -327,7 +327,7 @@ impl HeaderMap {
     /// assert!(map.contains_key(header::ACCEPT));
     /// ```
     pub fn contains_key(&self, key: impl AsHeaderName) -> bool {
-        match key.try_as_name() {
+        match key.try_as_name(super::as_name::Seal) {
             Ok(Cow::Borrowed(name)) => self.inner.contains_key(name),
             Ok(Cow::Owned(name)) => self.inner.contains_key(&name),
             Err(_) => false,
@@ -410,7 +410,7 @@ impl HeaderMap {
     ///
     /// assert!(map.is_empty());
     pub fn remove(&mut self, key: impl AsHeaderName) -> Removed {
-        let value = match key.try_as_name() {
+        let value = match key.try_as_name(super::as_name::Seal) {
             Ok(Cow::Borrowed(name)) => self.inner.remove(name),
             Ok(Cow::Owned(name)) => self.inner.remove(&name),
             Err(_) => None,
diff --git a/actix-http/src/header/shared/content_encoding.rs b/actix-http/src/header/shared/content_encoding.rs
index b93d66101..b9c1d2795 100644
--- a/actix-http/src/header/shared/content_encoding.rs
+++ b/actix-http/src/header/shared/content_encoding.rs
@@ -23,6 +23,9 @@ pub enum ContentEncoding {
     /// Gzip algorithm.
     Gzip,
 
+    // Zstd algorithm.
+    Zstd,
+
     /// Indicates the identity function (i.e. no compression, nor modification).
     Identity,
 }
@@ -41,6 +44,7 @@ impl ContentEncoding {
             ContentEncoding::Br => "br",
             ContentEncoding::Gzip => "gzip",
             ContentEncoding::Deflate => "deflate",
+            ContentEncoding::Zstd => "zstd",
             ContentEncoding::Identity | ContentEncoding::Auto => "identity",
         }
     }
@@ -53,6 +57,7 @@ impl ContentEncoding {
             ContentEncoding::Gzip => 1.0,
             ContentEncoding::Deflate => 0.9,
             ContentEncoding::Identity | ContentEncoding::Auto => 0.1,
+            ContentEncoding::Zstd => 0.0,
         }
     }
 }
@@ -81,6 +86,8 @@ impl From<&str> for ContentEncoding {
             ContentEncoding::Gzip
         } else if val.eq_ignore_ascii_case("deflate") {
             ContentEncoding::Deflate
+        } else if val.eq_ignore_ascii_case("zstd") {
+            ContentEncoding::Zstd
         } else {
             ContentEncoding::default()
         }
diff --git a/actix-http/src/helpers.rs b/actix-http/src/helpers.rs
index 34bb989f9..cba94d9b8 100644
--- a/actix-http/src/helpers.rs
+++ b/actix-http/src/helpers.rs
@@ -27,7 +27,9 @@ pub(crate) fn write_status_line<B: BufMut>(version: Version, n: u16, buf: &mut B
     buf.put_u8(b' ');
 }
 
-/// NOTE: bytes object has to contain enough space
+/// Write out content length header.
+///
+/// Buffer must to contain enough space or be implicitly extendable.
 pub fn write_content_length<B: BufMut>(n: u64, buf: &mut B) {
     if n == 0 {
         buf.put_slice(b"\r\ncontent-length: 0\r\n");
@@ -41,11 +43,15 @@ pub fn write_content_length<B: BufMut>(n: u64, buf: &mut B) {
     buf.put_slice(b"\r\n");
 }
 
-// TODO: bench why this is needed vs Buf::writer
-/// An `io` writer for a `BufMut` that should only be used once and on an empty buffer.
-pub(crate) struct Writer<'a, B>(pub &'a mut B);
+/// An `io::Write`r that only requires mutable reference and assumes that there is space available
+/// in the buffer for every write operation or that it can be extended implicitly (like
+/// `bytes::BytesMut`, for example).
+///
+/// This is slightly faster (~10%) than `bytes::buf::Writer` in such cases because it does not
+/// perform a remaining length check before writing.
+pub(crate) struct MutWriter<'a, B>(pub(crate) &'a mut B);
 
-impl<'a, B> io::Write for Writer<'a, B>
+impl<'a, B> io::Write for MutWriter<'a, B>
 where
     B: BufMut,
 {
diff --git a/actix-http/src/lib.rs b/actix-http/src/lib.rs
index 7c2c3b4e3..d22e1ee44 100644
--- a/actix-http/src/lib.rs
+++ b/actix-http/src/lib.rs
@@ -1,12 +1,14 @@
 //! HTTP primitives for the Actix ecosystem.
 //!
 //! ## Crate Features
-//! | Feature          | Functionality                                         |
-//! | ---------------- | ----------------------------------------------------- |
-//! | `openssl`        | TLS support via [OpenSSL].                            |
-//! | `rustls`         | TLS support via [rustls].                             |
-//! | `compress`       | Payload compression support. (Deflate, Gzip & Brotli) |
-//! | `trust-dns`      | Use [trust-dns] as the client DNS resolver.           |
+//! | Feature             | Functionality                               |
+//! | ------------------- | ------------------------------------------- |
+//! | `openssl`           | TLS support via [OpenSSL].                  |
+//! | `rustls`            | TLS support via [rustls].                   |
+//! | `compress-brotli`   | Payload compression support: Brotli.        |
+//! | `compress-gzip`     | Payload compression support: Deflate, Gzip. |
+//! | `compress-zstd`     | Payload compression support: Zstd.          |
+//! | `trust-dns`         | Use [trust-dns] as the client DNS resolver. |
 //!
 //! [OpenSSL]: https://crates.io/crates/openssl
 //! [rustls]: https://crates.io/crates/rustls
@@ -25,14 +27,12 @@
 #[macro_use]
 extern crate log;
 
-#[macro_use]
-mod macros;
-
 pub mod body;
 mod builder;
 pub mod client;
 mod config;
-#[cfg(feature = "compress")]
+
+#[cfg(feature = "__compress")]
 pub mod encoding;
 mod extensions;
 pub mod header;
@@ -54,7 +54,7 @@ pub mod ws;
 
 pub use self::builder::HttpServiceBuilder;
 pub use self::config::{KeepAlive, ServiceConfig};
-pub use self::error::{Error, ResponseError};
+pub use self::error::Error;
 pub use self::extensions::Extensions;
 pub use self::header::ContentEncoding;
 pub use self::http_message::HttpMessage;
diff --git a/actix-http/src/message.rs b/actix-http/src/message.rs
index 0a3f3a915..e85d686b7 100644
--- a/actix-http/src/message.rs
+++ b/actix-http/src/message.rs
@@ -152,15 +152,16 @@ impl RequestHead {
 
     /// Connection upgrade status
     pub fn upgrade(&self) -> bool {
-        if let Some(hdr) = self.headers().get(header::CONNECTION) {
-            if let Ok(s) = hdr.to_str() {
-                s.to_ascii_lowercase().contains("upgrade")
-            } else {
-                false
-            }
-        } else {
-            false
-        }
+        self.headers()
+            .get(header::CONNECTION)
+            .map(|hdr| {
+                if let Ok(s) = hdr.to_str() {
+                    s.to_ascii_lowercase().contains("upgrade")
+                } else {
+                    false
+                }
+            })
+            .unwrap_or(false)
     }
 
     #[inline]
@@ -308,13 +309,11 @@ impl ResponseHead {
     /// Get custom reason for the response
     #[inline]
     pub fn reason(&self) -> &str {
-        if let Some(reason) = self.reason {
-            reason
-        } else {
+        self.reason.unwrap_or_else(|| {
             self.status
                 .canonical_reason()
                 .unwrap_or("<unknown status code>")
-        }
+        })
     }
 
     #[inline]
@@ -356,7 +355,7 @@ pub struct Message<T: Head> {
 impl<T: Head> Message<T> {
     /// Get new message from the pool of objects
     pub fn new() -> Self {
-        T::with_pool(|p| p.get_message())
+        T::with_pool(MessagePool::get_message)
     }
 }
 
diff --git a/actix-http/src/response.rs b/actix-http/src/response.rs
index bcfa65732..2aa38c153 100644
--- a/actix-http/src/response.rs
+++ b/actix-http/src/response.rs
@@ -8,7 +8,7 @@ use std::{
 use bytes::{Bytes, BytesMut};
 
 use crate::{
-    body::{Body, MessageBody},
+    body::{AnyBody, MessageBody},
     error::Error,
     extensions::Extensions,
     http::{HeaderMap, StatusCode},
@@ -22,13 +22,13 @@ pub struct Response<B> {
     pub(crate) body: B,
 }
 
-impl Response<Body> {
+impl Response<AnyBody> {
     /// Constructs a new response with default body.
     #[inline]
-    pub fn new(status: StatusCode) -> Response<Body> {
+    pub fn new(status: StatusCode) -> Self {
         Response {
             head: BoxedResponseHead::new(status),
-            body: Body::Empty,
+            body: AnyBody::Empty,
         }
     }
 
@@ -43,40 +43,29 @@ impl Response<Body> {
 
     /// Constructs a new response with status 200 OK.
     #[inline]
-    pub fn ok() -> Response<Body> {
+    pub fn ok() -> Self {
         Response::new(StatusCode::OK)
     }
 
     /// Constructs a new response with status 400 Bad Request.
     #[inline]
-    pub fn bad_request() -> Response<Body> {
+    pub fn bad_request() -> Self {
         Response::new(StatusCode::BAD_REQUEST)
     }
 
     /// Constructs a new response with status 404 Not Found.
     #[inline]
-    pub fn not_found() -> Response<Body> {
+    pub fn not_found() -> Self {
         Response::new(StatusCode::NOT_FOUND)
     }
 
     /// Constructs a new response with status 500 Internal Server Error.
     #[inline]
-    pub fn internal_server_error() -> Response<Body> {
+    pub fn internal_server_error() -> Self {
         Response::new(StatusCode::INTERNAL_SERVER_ERROR)
     }
 
     // end shortcuts
-
-    /// Constructs a new response from an error.
-    #[inline]
-    pub fn from_error(error: impl Into<Error>) -> Response<Body> {
-        let error = error.into();
-        let resp = error.as_response_error().error_response();
-        if resp.head.status == StatusCode::INTERNAL_SERVER_ERROR {
-            debug!("Internal Server Error: {:?}", error);
-        }
-        resp
-    }
 }
 
 impl<B> Response<B> {
@@ -209,7 +198,6 @@ impl<B> Response<B> {
 impl<B> fmt::Debug for Response<B>
 where
     B: MessageBody,
-    B::Error: Into<Error>,
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let res = writeln!(
@@ -235,7 +223,9 @@ impl<B: Default> Default for Response<B> {
     }
 }
 
-impl<I: Into<Response<Body>>, E: Into<Error>> From<Result<I, E>> for Response<Body> {
+impl<I: Into<Response<AnyBody>>, E: Into<Error>> From<Result<I, E>>
+    for Response<AnyBody>
+{
     fn from(res: Result<I, E>) -> Self {
         match res {
             Ok(val) => val.into(),
@@ -244,13 +234,19 @@ impl<I: Into<Response<Body>>, E: Into<Error>> From<Result<I, E>> for Response<Bo
     }
 }
 
-impl From<ResponseBuilder> for Response<Body> {
+impl From<ResponseBuilder> for Response<AnyBody> {
     fn from(mut builder: ResponseBuilder) -> Self {
         builder.finish()
     }
 }
 
-impl From<&'static str> for Response<Body> {
+impl From<std::convert::Infallible> for Response<AnyBody> {
+    fn from(val: std::convert::Infallible) -> Self {
+        match val {}
+    }
+}
+
+impl From<&'static str> for Response<AnyBody> {
     fn from(val: &'static str) -> Self {
         Response::build(StatusCode::OK)
             .content_type(mime::TEXT_PLAIN_UTF_8)
@@ -258,7 +254,7 @@ impl From<&'static str> for Response<Body> {
     }
 }
 
-impl From<&'static [u8]> for Response<Body> {
+impl From<&'static [u8]> for Response<AnyBody> {
     fn from(val: &'static [u8]) -> Self {
         Response::build(StatusCode::OK)
             .content_type(mime::APPLICATION_OCTET_STREAM)
@@ -266,7 +262,7 @@ impl From<&'static [u8]> for Response<Body> {
     }
 }
 
-impl From<String> for Response<Body> {
+impl From<String> for Response<AnyBody> {
     fn from(val: String) -> Self {
         Response::build(StatusCode::OK)
             .content_type(mime::TEXT_PLAIN_UTF_8)
@@ -274,7 +270,7 @@ impl From<String> for Response<Body> {
     }
 }
 
-impl<'a> From<&'a String> for Response<Body> {
+impl<'a> From<&'a String> for Response<AnyBody> {
     fn from(val: &'a String) -> Self {
         Response::build(StatusCode::OK)
             .content_type(mime::TEXT_PLAIN_UTF_8)
@@ -282,7 +278,7 @@ impl<'a> From<&'a String> for Response<Body> {
     }
 }
 
-impl From<Bytes> for Response<Body> {
+impl From<Bytes> for Response<AnyBody> {
     fn from(val: Bytes) -> Self {
         Response::build(StatusCode::OK)
             .content_type(mime::APPLICATION_OCTET_STREAM)
@@ -290,7 +286,7 @@ impl From<Bytes> for Response<Body> {
     }
 }
 
-impl From<BytesMut> for Response<Body> {
+impl From<BytesMut> for Response<AnyBody> {
     fn from(val: BytesMut) -> Self {
         Response::build(StatusCode::OK)
             .content_type(mime::APPLICATION_OCTET_STREAM)
@@ -301,7 +297,6 @@ impl From<BytesMut> for Response<Body> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::body::Body;
     use crate::http::header::{HeaderValue, CONTENT_TYPE, COOKIE};
 
     #[test]
@@ -316,7 +311,7 @@ mod tests {
 
     #[test]
     fn test_into_response() {
-        let resp: Response<Body> = "test".into();
+        let resp: Response<AnyBody> = "test".into();
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap(),
@@ -325,7 +320,7 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(resp.body().get_ref(), b"test");
 
-        let resp: Response<Body> = b"test".as_ref().into();
+        let resp: Response<AnyBody> = b"test".as_ref().into();
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap(),
@@ -334,7 +329,7 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(resp.body().get_ref(), b"test");
 
-        let resp: Response<Body> = "test".to_owned().into();
+        let resp: Response<AnyBody> = "test".to_owned().into();
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap(),
@@ -343,7 +338,7 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(resp.body().get_ref(), b"test");
 
-        let resp: Response<Body> = (&"test".to_owned()).into();
+        let resp: Response<AnyBody> = (&"test".to_owned()).into();
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap(),
@@ -353,7 +348,7 @@ mod tests {
         assert_eq!(resp.body().get_ref(), b"test");
 
         let b = Bytes::from_static(b"test");
-        let resp: Response<Body> = b.into();
+        let resp: Response<AnyBody> = b.into();
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap(),
@@ -363,7 +358,7 @@ mod tests {
         assert_eq!(resp.body().get_ref(), b"test");
 
         let b = Bytes::from_static(b"test");
-        let resp: Response<Body> = b.into();
+        let resp: Response<AnyBody> = b.into();
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap(),
@@ -373,7 +368,7 @@ mod tests {
         assert_eq!(resp.body().get_ref(), b"test");
 
         let b = BytesMut::from("test");
-        let resp: Response<Body> = b.into();
+        let resp: Response<AnyBody> = b.into();
         assert_eq!(resp.status(), StatusCode::OK);
         assert_eq!(
             resp.headers().get(CONTENT_TYPE).unwrap(),
diff --git a/actix-http/src/response_builder.rs b/actix-http/src/response_builder.rs
index df9079d70..e46d9a28c 100644
--- a/actix-http/src/response_builder.rs
+++ b/actix-http/src/response_builder.rs
@@ -2,6 +2,7 @@
 
 use std::{
     cell::{Ref, RefMut},
+    error::Error as StdError,
     fmt,
     future::Future,
     pin::Pin,
@@ -13,7 +14,7 @@ use bytes::Bytes;
 use futures_core::Stream;
 
 use crate::{
-    body::{Body, BodyStream},
+    body::{AnyBody, BodyStream},
     error::{Error, HttpError},
     header::{self, IntoHeaderPair, IntoHeaderValue},
     message::{BoxedResponseHead, ConnectionType, ResponseHead},
@@ -235,9 +236,9 @@ impl ResponseBuilder {
     ///
     /// This `ResponseBuilder` will be left in a useless state.
     #[inline]
-    pub fn body<B: Into<Body>>(&mut self, body: B) -> Response<Body> {
+    pub fn body<B: Into<AnyBody>>(&mut self, body: B) -> Response<AnyBody> {
         self.message_body(body.into())
-            .unwrap_or_else(Response::from_error)
+            .unwrap_or_else(Response::from)
     }
 
     /// Generate response with a body.
@@ -245,7 +246,7 @@ impl ResponseBuilder {
     /// This `ResponseBuilder` will be left in a useless state.
     pub fn message_body<B>(&mut self, body: B) -> Result<Response<B>, Error> {
         if let Some(err) = self.err.take() {
-            return Err(err.into());
+            return Err(Error::new_http().with_cause(err));
         }
 
         let head = self.head.take().expect("cannot reuse response builder");
@@ -256,20 +257,20 @@ impl ResponseBuilder {
     ///
     /// This `ResponseBuilder` will be left in a useless state.
     #[inline]
-    pub fn streaming<S, E>(&mut self, stream: S) -> Response<Body>
+    pub fn streaming<S, E>(&mut self, stream: S) -> Response<AnyBody>
     where
-        S: Stream<Item = Result<Bytes, E>> + Unpin + 'static,
-        E: Into<Error> + 'static,
+        S: Stream<Item = Result<Bytes, E>> + 'static,
+        E: Into<Box<dyn StdError>> + 'static,
     {
-        self.body(Body::from_message(BodyStream::new(stream)))
+        self.body(AnyBody::from_message(BodyStream::new(stream)))
     }
 
     /// Generate response with an empty body.
     ///
     /// This `ResponseBuilder` will be left in a useless state.
     #[inline]
-    pub fn finish(&mut self) -> Response<Body> {
-        self.body(Body::Empty)
+    pub fn finish(&mut self) -> Response<AnyBody> {
+        self.body(AnyBody::Empty)
     }
 
     /// Create an owned `ResponseBuilder`, leaving the original in a useless state.
@@ -327,7 +328,7 @@ impl<'a> From<&'a ResponseHead> for ResponseBuilder {
 }
 
 impl Future for ResponseBuilder {
-    type Output = Result<Response<Body>, Error>;
+    type Output = Result<Response<AnyBody>, Error>;
 
     fn poll(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> {
         Poll::Ready(Ok(self.finish()))
diff --git a/actix-http/src/service.rs b/actix-http/src/service.rs
index d25a67a19..afe47bf2d 100644
--- a/actix-http/src/service.rs
+++ b/actix-http/src/service.rs
@@ -1,4 +1,5 @@
 use std::{
+    error::Error as StdError,
     fmt,
     future::Future,
     marker::PhantomData,
@@ -8,6 +9,7 @@ use std::{
     task::{Context, Poll},
 };
 
+use ::h2::server::{handshake as h2_handshake, Handshake as H2Handshake};
 use actix_codec::{AsyncRead, AsyncWrite, Framed};
 use actix_rt::net::TcpStream;
 use actix_service::{
@@ -15,16 +17,15 @@ use actix_service::{
 };
 use bytes::Bytes;
 use futures_core::{future::LocalBoxFuture, ready};
-use h2::server::{handshake, Handshake};
 use pin_project::pin_project;
 
-use crate::body::MessageBody;
-use crate::builder::HttpServiceBuilder;
-use crate::config::{KeepAlive, ServiceConfig};
-use crate::error::{DispatchError, Error};
-use crate::request::Request;
-use crate::response::Response;
-use crate::{h1, h2::Dispatcher, ConnectCallback, OnConnectData, Protocol};
+use crate::{
+    body::{AnyBody, MessageBody},
+    builder::HttpServiceBuilder,
+    config::{KeepAlive, ServiceConfig},
+    error::DispatchError,
+    h1, h2, ConnectCallback, OnConnectData, Protocol, Request, Response,
+};
 
 /// A `ServiceFactory` for HTTP/1.1 or HTTP/2 protocol.
 pub struct HttpService<T, S, B, X = h1::ExpectHandler, U = h1::UpgradeHandler> {
@@ -39,7 +40,7 @@ pub struct HttpService<T, S, B, X = h1::ExpectHandler, U = h1::UpgradeHandler> {
 impl<T, S, B> HttpService<T, S, B>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
@@ -54,12 +55,12 @@ where
 impl<T, S, B> HttpService<T, S, B>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     /// Create new `HttpService` instance.
     pub fn new<F: IntoServiceFactory<S, Request>>(service: F) -> Self {
@@ -94,7 +95,7 @@ where
 impl<T, S, B, X, U> HttpService<T, S, B, X, U>
 where
     S: ServiceFactory<Request, Config = ()>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
@@ -108,7 +109,7 @@ where
     pub fn expect<X1>(self, expect: X1) -> HttpService<T, S, B, X1, U>
     where
         X1: ServiceFactory<Request, Config = (), Response = Request>,
-        X1::Error: Into<Error>,
+        X1::Error: Into<Response<AnyBody>>,
         X1::InitError: fmt::Debug,
     {
         HttpService {
@@ -152,17 +153,17 @@ impl<S, B, X, U> HttpService<TcpStream, S, B, X, U>
 where
     S: ServiceFactory<Request, Config = ()>,
     S::Future: 'static,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
 
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: ServiceFactory<Request, Config = (), Response = Request>,
     X::Future: 'static,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
     X::InitError: fmt::Debug,
 
     U: ServiceFactory<
@@ -171,7 +172,7 @@ where
         Response = (),
     >,
     U::Future: 'static,
-    U::Error: fmt::Display + Into<Error>,
+    U::Error: fmt::Display + Into<Response<AnyBody>>,
     U::InitError: fmt::Debug,
 {
     /// Create simple tcp stream service
@@ -204,17 +205,17 @@ mod openssl {
     where
         S: ServiceFactory<Request, Config = ()>,
         S::Future: 'static,
-        S::Error: Into<Error> + 'static,
+        S::Error: Into<Response<AnyBody>> + 'static,
         S::InitError: fmt::Debug,
         S::Response: Into<Response<B>> + 'static,
         <S::Service as Service<Request>>::Future: 'static,
 
         B: MessageBody + 'static,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
 
         X: ServiceFactory<Request, Config = (), Response = Request>,
         X::Future: 'static,
-        X::Error: Into<Error>,
+        X::Error: Into<Response<AnyBody>>,
         X::InitError: fmt::Debug,
 
         U: ServiceFactory<
@@ -223,7 +224,7 @@ mod openssl {
             Response = (),
         >,
         U::Future: 'static,
-        U::Error: fmt::Display + Into<Error>,
+        U::Error: fmt::Display + Into<Response<AnyBody>>,
         U::InitError: fmt::Debug,
     {
         /// Create openssl based service
@@ -272,17 +273,17 @@ mod rustls {
     where
         S: ServiceFactory<Request, Config = ()>,
         S::Future: 'static,
-        S::Error: Into<Error> + 'static,
+        S::Error: Into<Response<AnyBody>> + 'static,
         S::InitError: fmt::Debug,
         S::Response: Into<Response<B>> + 'static,
         <S::Service as Service<Request>>::Future: 'static,
 
         B: MessageBody + 'static,
-        B::Error: Into<Error>,
+        B::Error: Into<Box<dyn StdError>>,
 
         X: ServiceFactory<Request, Config = (), Response = Request>,
         X::Future: 'static,
-        X::Error: Into<Error>,
+        X::Error: Into<Response<AnyBody>>,
         X::InitError: fmt::Debug,
 
         U: ServiceFactory<
@@ -291,7 +292,7 @@ mod rustls {
             Response = (),
         >,
         U::Future: 'static,
-        U::Error: fmt::Display + Into<Error>,
+        U::Error: fmt::Display + Into<Response<AnyBody>>,
         U::InitError: fmt::Debug,
     {
         /// Create rustls based service
@@ -305,7 +306,8 @@ mod rustls {
             Error = TlsError<io::Error, DispatchError>,
             InitError = (),
         > {
-            let protos = vec!["h2".to_string().into(), "http/1.1".to_string().into()];
+            let mut protos = vec![b"h2".to_vec(), b"http/1.1".to_vec()];
+            protos.extend_from_slice(&config.alpn_protocols);
             config.set_protocols(&protos);
 
             Acceptor::new(config)
@@ -337,22 +339,22 @@ where
 
     S: ServiceFactory<Request, Config = ()>,
     S::Future: 'static,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
 
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: ServiceFactory<Request, Config = (), Response = Request>,
     X::Future: 'static,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
     X::InitError: fmt::Debug,
 
     U: ServiceFactory<(Request, Framed<T, h1::Codec>), Config = (), Response = ()>,
     U::Future: 'static,
-    U::Error: fmt::Display + Into<Error>,
+    U::Error: fmt::Display + Into<Response<AnyBody>>,
     U::InitError: fmt::Debug,
 {
     type Response = ();
@@ -415,11 +417,11 @@ where
 impl<T, S, B, X, U> HttpServiceHandler<T, S, B, X, U>
 where
     S: Service<Request>,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
     X: Service<Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
     U: Service<(Request, Framed<T, h1::Codec>)>,
-    U::Error: Into<Error>,
+    U::Error: Into<Response<AnyBody>>,
 {
     pub(super) fn new(
         cfg: ServiceConfig,
@@ -436,7 +438,10 @@ where
         }
     }
 
-    pub(super) fn _poll_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Error>> {
+    pub(super) fn _poll_ready(
+        &self,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<(), Response<AnyBody>>> {
         ready!(self.flow.expect.poll_ready(cx).map_err(Into::into))?;
 
         ready!(self.flow.service.poll_ready(cx).map_err(Into::into))?;
@@ -472,18 +477,18 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
 
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, h1::Codec>), Response = ()>,
-    U::Error: fmt::Display + Into<Error>,
+    U::Error: fmt::Display + Into<Response<AnyBody>>,
 {
     type Response = ();
     type Error = DispatchError;
@@ -506,7 +511,7 @@ where
         match proto {
             Protocol::Http2 => HttpServiceHandlerResponse {
                 state: State::H2Handshake(Some((
-                    handshake(io),
+                    h2_handshake(io),
                     self.cfg.clone(),
                     self.flow.clone(),
                     on_connect_data,
@@ -536,22 +541,22 @@ where
 
     S: Service<Request>,
     S::Future: 'static,
-    S::Error: Into<Error>,
+    S::Error: Into<Response<AnyBody>>,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, h1::Codec>), Response = ()>,
     U::Error: fmt::Display,
 {
     H1(#[pin] h1::Dispatcher<T, S, B, X, U>),
-    H2(#[pin] Dispatcher<T, S, B, X, U>),
+    H2(#[pin] h2::Dispatcher<T, S, B, X, U>),
     H2Handshake(
         Option<(
-            Handshake<T, Bytes>,
+            H2Handshake<T, Bytes>,
             ServiceConfig,
             Rc<HttpFlow<S, X, U>>,
             OnConnectData,
@@ -566,15 +571,15 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
 
     B: MessageBody,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, h1::Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -588,15 +593,15 @@ where
     T: AsyncRead + AsyncWrite + Unpin,
 
     S: Service<Request>,
-    S::Error: Into<Error> + 'static,
+    S::Error: Into<Response<AnyBody>> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
 
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 
     X: Service<Request, Response = Request>,
-    X::Error: Into<Error>,
+    X::Error: Into<Response<AnyBody>>,
 
     U: Service<(Request, Framed<T, h1::Codec>), Response = ()>,
     U::Error: fmt::Display,
@@ -612,13 +617,15 @@ where
                     Ok(conn) => {
                         let (_, cfg, srv, on_connect_data, peer_addr) =
                             data.take().unwrap();
-                        self.as_mut().project().state.set(State::H2(Dispatcher::new(
-                            srv,
-                            conn,
-                            on_connect_data,
-                            cfg,
-                            peer_addr,
-                        )));
+                        self.as_mut().project().state.set(State::H2(
+                            h2::Dispatcher::new(
+                                srv,
+                                conn,
+                                on_connect_data,
+                                cfg,
+                                peer_addr,
+                            ),
+                        ));
                         self.poll(cx)
                     }
                     Err(err) => {
diff --git a/actix-http/src/ws/dispatcher.rs b/actix-http/src/ws/dispatcher.rs
index 576851139..f49cbe5d4 100644
--- a/actix-http/src/ws/dispatcher.rs
+++ b/actix-http/src/ws/dispatcher.rs
@@ -72,7 +72,7 @@ mod inner {
 
     use actix_codec::{AsyncRead, AsyncWrite, Decoder, Encoder, Framed};
 
-    use crate::ResponseError;
+    use crate::{body::AnyBody, Response};
 
     /// Framed transport errors
     pub enum DispatcherError<E, U, I>
@@ -136,13 +136,16 @@ mod inner {
         }
     }
 
-    impl<E, U, I> ResponseError for DispatcherError<E, U, I>
+    impl<E, U, I> From<DispatcherError<E, U, I>> for Response<AnyBody>
     where
         E: fmt::Debug + fmt::Display,
         U: Encoder<I> + Decoder,
         <U as Encoder<I>>::Error: fmt::Debug,
         <U as Decoder>::Error: fmt::Debug,
     {
+        fn from(err: DispatcherError<E, U, I>) -> Self {
+            Response::internal_server_error().set_body(AnyBody::from(err.to_string()))
+        }
     }
 
     /// Message type wrapper for signalling end of message stream.
diff --git a/actix-http/src/ws/mod.rs b/actix-http/src/ws/mod.rs
index 22df2b4ff..7df924cf5 100644
--- a/actix-http/src/ws/mod.rs
+++ b/actix-http/src/ws/mod.rs
@@ -9,8 +9,8 @@ use derive_more::{Display, Error, From};
 use http::{header, Method, StatusCode};
 
 use crate::{
-    body::Body, error::ResponseError, header::HeaderValue, message::RequestHead,
-    response::Response, ResponseBuilder,
+    body::AnyBody, header::HeaderValue, message::RequestHead, response::Response,
+    ResponseBuilder,
 };
 
 mod codec;
@@ -25,7 +25,7 @@ pub use self::frame::Parser;
 pub use self::proto::{hash_key, CloseCode, CloseReason, OpCode};
 
 /// WebSocket protocol errors.
-#[derive(Debug, Display, From, Error)]
+#[derive(Debug, Display, Error, From)]
 pub enum ProtocolError {
     /// Received an unmasked frame from client.
     #[display(fmt = "Received an unmasked frame from client.")]
@@ -68,10 +68,8 @@ pub enum ProtocolError {
     Io(io::Error),
 }
 
-impl ResponseError for ProtocolError {}
-
 /// WebSocket handshake errors
-#[derive(PartialEq, Debug, Display)]
+#[derive(Debug, PartialEq, Display, Error)]
 pub enum HandshakeError {
     /// Only get method is allowed.
     #[display(fmt = "Method not allowed.")]
@@ -98,44 +96,55 @@ pub enum HandshakeError {
     BadWebsocketKey,
 }
 
-impl ResponseError for HandshakeError {
-    fn error_response(&self) -> Response<Body> {
-        match self {
+impl From<&HandshakeError> for Response<AnyBody> {
+    fn from(err: &HandshakeError) -> Self {
+        match err {
             HandshakeError::GetMethodRequired => {
-                Response::build(StatusCode::METHOD_NOT_ALLOWED)
-                    .insert_header((header::ALLOW, "GET"))
-                    .finish()
+                let mut res = Response::new(StatusCode::METHOD_NOT_ALLOWED);
+                res.headers_mut()
+                    .insert(header::ALLOW, HeaderValue::from_static("GET"));
+                res
             }
 
             HandshakeError::NoWebsocketUpgrade => {
-                Response::build(StatusCode::BAD_REQUEST)
-                    .reason("No WebSocket Upgrade header found")
-                    .finish()
+                let mut res = Response::bad_request();
+                res.head_mut().reason = Some("No WebSocket Upgrade header found");
+                res
             }
 
             HandshakeError::NoConnectionUpgrade => {
-                Response::build(StatusCode::BAD_REQUEST)
-                    .reason("No Connection upgrade")
-                    .finish()
+                let mut res = Response::bad_request();
+                res.head_mut().reason = Some("No Connection upgrade");
+                res
             }
 
-            HandshakeError::NoVersionHeader => Response::build(StatusCode::BAD_REQUEST)
-                .reason("WebSocket version header is required")
-                .finish(),
+            HandshakeError::NoVersionHeader => {
+                let mut res = Response::bad_request();
+                res.head_mut().reason = Some("WebSocket version header is required");
+                res
+            }
 
             HandshakeError::UnsupportedVersion => {
-                Response::build(StatusCode::BAD_REQUEST)
-                    .reason("Unsupported WebSocket version")
-                    .finish()
+                let mut res = Response::bad_request();
+                res.head_mut().reason = Some("Unsupported WebSocket version");
+                res
             }
 
-            HandshakeError::BadWebsocketKey => Response::build(StatusCode::BAD_REQUEST)
-                .reason("Handshake error")
-                .finish(),
+            HandshakeError::BadWebsocketKey => {
+                let mut res = Response::bad_request();
+                res.head_mut().reason = Some("Handshake error");
+                res
+            }
         }
     }
 }
 
+impl From<HandshakeError> for Response<AnyBody> {
+    fn from(err: HandshakeError) -> Self {
+        (&err).into()
+    }
+}
+
 /// Verify WebSocket handshake request and create handshake response.
 pub fn handshake(req: &RequestHead) -> Result<ResponseBuilder, HandshakeError> {
     verify_handshake(req)?;
@@ -213,7 +222,7 @@ pub fn handshake_response(req: &RequestHead) -> ResponseBuilder {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::test::TestRequest;
+    use crate::{body::AnyBody, test::TestRequest};
     use http::{header, Method};
 
     #[test]
@@ -327,18 +336,18 @@ mod tests {
     }
 
     #[test]
-    fn test_wserror_http_response() {
-        let resp = HandshakeError::GetMethodRequired.error_response();
+    fn test_ws_error_http_response() {
+        let resp: Response<AnyBody> = HandshakeError::GetMethodRequired.into();
         assert_eq!(resp.status(), StatusCode::METHOD_NOT_ALLOWED);
-        let resp = HandshakeError::NoWebsocketUpgrade.error_response();
+        let resp: Response<AnyBody> = HandshakeError::NoWebsocketUpgrade.into();
         assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
-        let resp = HandshakeError::NoConnectionUpgrade.error_response();
+        let resp: Response<AnyBody> = HandshakeError::NoConnectionUpgrade.into();
         assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
-        let resp = HandshakeError::NoVersionHeader.error_response();
+        let resp: Response<AnyBody> = HandshakeError::NoVersionHeader.into();
         assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
-        let resp = HandshakeError::UnsupportedVersion.error_response();
+        let resp: Response<AnyBody> = HandshakeError::UnsupportedVersion.into();
         assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
-        let resp = HandshakeError::BadWebsocketKey.error_response();
+        let resp: Response<AnyBody> = HandshakeError::BadWebsocketKey.into();
         assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
     }
 }
diff --git a/actix-http/tests/test_client.rs b/actix-http/tests/test_client.rs
index 4bd7dbe14..414266d81 100644
--- a/actix-http/tests/test_client.rs
+++ b/actix-http/tests/test_client.rs
@@ -1,5 +1,7 @@
+use std::convert::Infallible;
+
 use actix_http::{
-    http, http::StatusCode, HttpMessage, HttpService, Request, Response, ResponseError,
+    body::AnyBody, http, http::StatusCode, HttpMessage, HttpService, Request, Response,
 };
 use actix_http_test::test_server;
 use actix_service::ServiceFactoryExt;
@@ -34,7 +36,7 @@ const STR: &str = "Hello World Hello World Hello World Hello World Hello World \
 async fn test_h1_v2() {
     let srv = test_server(move || {
         HttpService::build()
-            .finish(|_| future::ok::<_, ()>(Response::ok().set_body(STR)))
+            .finish(|_| future::ok::<_, Infallible>(Response::ok().set_body(STR)))
             .tcp()
     })
     .await;
@@ -62,7 +64,7 @@ async fn test_h1_v2() {
 async fn test_connection_close() {
     let srv = test_server(move || {
         HttpService::build()
-            .finish(|_| future::ok::<_, ()>(Response::ok().set_body(STR)))
+            .finish(|_| future::ok::<_, Infallible>(Response::ok().set_body(STR)))
             .tcp()
             .map(|_| ())
     })
@@ -76,11 +78,11 @@ async fn test_connection_close() {
 async fn test_with_query_parameter() {
     let srv = test_server(move || {
         HttpService::build()
-            .finish(|req: Request| {
+            .finish(|req: Request| async move {
                 if req.uri().query().unwrap().contains("qp=") {
-                    future::ok::<_, ()>(Response::ok())
+                    Ok::<_, Infallible>(Response::ok())
                 } else {
-                    future::ok::<_, ()>(Response::bad_request())
+                    Ok(Response::bad_request())
                 }
             })
             .tcp()
@@ -97,9 +99,9 @@ async fn test_with_query_parameter() {
 #[display(fmt = "expect failed")]
 struct ExpectFailed;
 
-impl ResponseError for ExpectFailed {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::EXPECTATION_FAILED
+impl From<ExpectFailed> for Response<AnyBody> {
+    fn from(_: ExpectFailed) -> Self {
+        Response::new(StatusCode::EXPECTATION_FAILED)
     }
 }
 
@@ -123,7 +125,7 @@ async fn test_h1_expect() {
                 let str = std::str::from_utf8(&buf).unwrap();
                 assert_eq!(str, "expect body");
 
-                Ok::<_, ()>(Response::ok())
+                Ok::<_, Infallible>(Response::ok())
             })
             .tcp()
     })
diff --git a/actix-http/tests/test_openssl.rs b/actix-http/tests/test_openssl.rs
index d3a3bea3b..a58d0cc70 100644
--- a/actix-http/tests/test_openssl.rs
+++ b/actix-http/tests/test_openssl.rs
@@ -2,16 +2,16 @@
 
 extern crate tls_openssl as openssl;
 
-use std::io;
+use std::{convert::Infallible, io};
 
 use actix_http::{
-    body::{Body, SizedStream},
+    body::{AnyBody, Body, SizedStream},
     error::PayloadError,
     http::{
         header::{self, HeaderName, HeaderValue},
         Method, StatusCode, Version,
     },
-    Error, HttpMessage, HttpService, Request, Response, ResponseError,
+    Error, HttpMessage, HttpService, Request, Response,
 };
 use actix_http_test::test_server;
 use actix_service::{fn_service, ServiceFactoryExt};
@@ -136,7 +136,7 @@ async fn test_h2_content_length() {
                     StatusCode::OK,
                     StatusCode::NOT_FOUND,
                 ];
-                ok::<_, ()>(Response::new(statuses[idx]))
+                ok::<_, Infallible>(Response::new(statuses[idx]))
             })
             .openssl(tls_config())
             .map_err(|_| ())
@@ -206,7 +206,7 @@ async fn test_h2_headers() {
                         TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST ",
                 ));
             }
-            ok::<_, ()>(builder.body(data.clone()))
+            ok::<_, Infallible>(builder.body(data.clone()))
         })
             .openssl(tls_config())
                     .map_err(|_| ())
@@ -246,7 +246,7 @@ const STR: &str = "Hello World Hello World Hello World Hello World Hello World \
 async fn test_h2_body2() {
     let mut srv = test_server(move || {
         HttpService::build()
-            .h2(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h2(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .openssl(tls_config())
             .map_err(|_| ())
     })
@@ -264,7 +264,7 @@ async fn test_h2_body2() {
 async fn test_h2_head_empty() {
     let mut srv = test_server(move || {
         HttpService::build()
-            .finish(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .finish(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .openssl(tls_config())
             .map_err(|_| ())
     })
@@ -288,7 +288,7 @@ async fn test_h2_head_empty() {
 async fn test_h2_head_binary() {
     let mut srv = test_server(move || {
         HttpService::build()
-            .h2(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h2(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .openssl(tls_config())
             .map_err(|_| ())
     })
@@ -311,7 +311,7 @@ async fn test_h2_head_binary() {
 async fn test_h2_head_binary2() {
     let srv = test_server(move || {
         HttpService::build()
-            .h2(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h2(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .openssl(tls_config())
             .map_err(|_| ())
     })
@@ -330,9 +330,12 @@ async fn test_h2_head_binary2() {
 async fn test_h2_body_length() {
     let mut srv = test_server(move || {
         HttpService::build()
-            .h2(|_| {
-                let body = once(ok(Bytes::from_static(STR.as_ref())));
-                ok::<_, ()>(
+            .h2(|_| async {
+                let body = once(async {
+                    Ok::<_, Infallible>(Bytes::from_static(STR.as_ref()))
+                });
+
+                Ok::<_, Infallible>(
                     Response::ok().set_body(SizedStream::new(STR.len() as u64, body)),
                 )
             })
@@ -355,7 +358,7 @@ async fn test_h2_body_chunked_explicit() {
         HttpService::build()
             .h2(|_| {
                 let body = once(ok::<_, Error>(Bytes::from_static(STR.as_ref())));
-                ok::<_, ()>(
+                ok::<_, Infallible>(
                     Response::build(StatusCode::OK)
                         .insert_header((header::TRANSFER_ENCODING, "chunked"))
                         .streaming(body),
@@ -383,7 +386,7 @@ async fn test_h2_response_http_error_handling() {
         HttpService::build()
             .h2(fn_service(|_| {
                 let broken_header = Bytes::from_static(b"\0\0\0");
-                ok::<_, ()>(
+                ok::<_, Infallible>(
                     Response::build(StatusCode::OK)
                         .insert_header((header::CONTENT_TYPE, broken_header))
                         .body(STR),
@@ -399,16 +402,19 @@ async fn test_h2_response_http_error_handling() {
 
     // read response
     let bytes = srv.load_body(response).await.unwrap();
-    assert_eq!(bytes, Bytes::from_static(b"failed to parse header value"));
+    assert_eq!(
+        bytes,
+        Bytes::from_static(b"error processing HTTP: failed to parse header value")
+    );
 }
 
 #[derive(Debug, Display, Error)]
 #[display(fmt = "error")]
 struct BadRequest;
 
-impl ResponseError for BadRequest {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
+impl From<BadRequest> for Response<AnyBody> {
+    fn from(err: BadRequest) -> Self {
+        Response::build(StatusCode::BAD_REQUEST).body(err.to_string())
     }
 }
 
@@ -439,7 +445,7 @@ async fn test_h2_on_connect() {
             })
             .h2(|req: Request| {
                 assert!(req.extensions().contains::<isize>());
-                ok::<_, ()>(Response::ok())
+                ok::<_, Infallible>(Response::ok())
             })
             .openssl(tls_config())
             .map_err(|_| ())
diff --git a/actix-http/tests/test_rustls.rs b/actix-http/tests/test_rustls.rs
index 2382d1ad3..cb7c77ad6 100644
--- a/actix-http/tests/test_rustls.rs
+++ b/actix-http/tests/test_rustls.rs
@@ -2,14 +2,21 @@
 
 extern crate tls_rustls as rustls;
 
+use std::{
+    convert::Infallible,
+    io::{self, BufReader, Write},
+    net::{SocketAddr, TcpStream as StdTcpStream},
+    sync::Arc,
+};
+
 use actix_http::{
-    body::{Body, SizedStream},
+    body::{AnyBody, Body, SizedStream},
     error::PayloadError,
     http::{
         header::{self, HeaderName, HeaderValue},
         Method, StatusCode, Version,
     },
-    Error, HttpService, Request, Response, ResponseError,
+    Error, HttpService, Request, Response,
 };
 use actix_http_test::test_server;
 use actix_service::{fn_factory_with_config, fn_service};
@@ -20,10 +27,9 @@ use futures_core::Stream;
 use futures_util::stream::{once, StreamExt as _};
 use rustls::{
     internal::pemfile::{certs, pkcs8_private_keys},
-    NoClientAuth, ServerConfig as RustlsServerConfig,
+    NoClientAuth, ServerConfig as RustlsServerConfig, Session,
 };
-
-use std::io::{self, BufReader};
+use webpki::DNSNameRef;
 
 async fn load_body<S>(mut stream: S) -> Result<BytesMut, PayloadError>
 where
@@ -52,6 +58,25 @@ fn tls_config() -> RustlsServerConfig {
     config
 }
 
+pub fn get_negotiated_alpn_protocol(
+    addr: SocketAddr,
+    client_alpn_protocol: &[u8],
+) -> Option<Vec<u8>> {
+    let mut config = rustls::ClientConfig::new();
+    config.alpn_protocols.push(client_alpn_protocol.to_vec());
+    let mut sess = rustls::ClientSession::new(
+        &Arc::new(config),
+        DNSNameRef::try_from_ascii_str("localhost").unwrap(),
+    );
+    let mut sock = StdTcpStream::connect(addr).unwrap();
+    let mut stream = rustls::Stream::new(&mut sess, &mut sock);
+    // The handshake will fails because the client will not be able to verify the server
+    // certificate, but it doesn't matter here as we are just interested in the negotiated ALPN
+    // protocol
+    let _ = stream.flush();
+    sess.get_alpn_protocol().map(|proto| proto.to_vec())
+}
+
 #[actix_rt::test]
 async fn test_h1() -> io::Result<()> {
     let srv = test_server(move || {
@@ -149,7 +174,7 @@ async fn test_h2_content_length() {
                     StatusCode::OK,
                     StatusCode::NOT_FOUND,
                 ];
-                ok::<_, ()>(Response::new(statuses[indx]))
+                ok::<_, Infallible>(Response::new(statuses[indx]))
             })
             .rustls(tls_config())
     })
@@ -218,7 +243,7 @@ async fn test_h2_headers() {
                         TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST ",
                 ));
             }
-            ok::<_, ()>(config.body(data.clone()))
+            ok::<_, Infallible>(config.body(data.clone()))
         })
             .rustls(tls_config())
     }).await;
@@ -257,7 +282,7 @@ const STR: &str = "Hello World Hello World Hello World Hello World Hello World \
 async fn test_h2_body2() {
     let mut srv = test_server(move || {
         HttpService::build()
-            .h2(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h2(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .rustls(tls_config())
     })
     .await;
@@ -274,7 +299,7 @@ async fn test_h2_body2() {
 async fn test_h2_head_empty() {
     let mut srv = test_server(move || {
         HttpService::build()
-            .finish(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .finish(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .rustls(tls_config())
     })
     .await;
@@ -300,7 +325,7 @@ async fn test_h2_head_empty() {
 async fn test_h2_head_binary() {
     let mut srv = test_server(move || {
         HttpService::build()
-            .h2(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h2(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .rustls(tls_config())
     })
     .await;
@@ -325,7 +350,7 @@ async fn test_h2_head_binary() {
 async fn test_h2_head_binary2() {
     let srv = test_server(move || {
         HttpService::build()
-            .h2(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h2(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .rustls(tls_config())
     })
     .await;
@@ -347,8 +372,8 @@ async fn test_h2_body_length() {
     let mut srv = test_server(move || {
         HttpService::build()
             .h2(|_| {
-                let body = once(ok(Bytes::from_static(STR.as_ref())));
-                ok::<_, ()>(
+                let body = once(ok::<_, Infallible>(Bytes::from_static(STR.as_ref())));
+                ok::<_, Infallible>(
                     Response::ok().set_body(SizedStream::new(STR.len() as u64, body)),
                 )
             })
@@ -370,7 +395,7 @@ async fn test_h2_body_chunked_explicit() {
         HttpService::build()
             .h2(|_| {
                 let body = once(ok::<_, Error>(Bytes::from_static(STR.as_ref())));
-                ok::<_, ()>(
+                ok::<_, Infallible>(
                     Response::build(StatusCode::OK)
                         .insert_header((header::TRANSFER_ENCODING, "chunked"))
                         .streaming(body),
@@ -396,9 +421,9 @@ async fn test_h2_response_http_error_handling() {
     let mut srv = test_server(move || {
         HttpService::build()
             .h2(fn_factory_with_config(|_: ()| {
-                ok::<_, ()>(fn_service(|_| {
+                ok::<_, Infallible>(fn_service(|_| {
                     let broken_header = Bytes::from_static(b"\0\0\0");
-                    ok::<_, ()>(
+                    ok::<_, Infallible>(
                         Response::build(StatusCode::OK)
                             .insert_header((http::header::CONTENT_TYPE, broken_header))
                             .body(STR),
@@ -414,16 +439,19 @@ async fn test_h2_response_http_error_handling() {
 
     // read response
     let bytes = srv.load_body(response).await.unwrap();
-    assert_eq!(bytes, Bytes::from_static(b"failed to parse header value"));
+    assert_eq!(
+        bytes,
+        Bytes::from_static(b"error processing HTTP: failed to parse header value")
+    );
 }
 
 #[derive(Debug, Display, Error)]
 #[display(fmt = "error")]
 struct BadRequest;
 
-impl ResponseError for BadRequest {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
+impl From<BadRequest> for Response<AnyBody> {
+    fn from(_: BadRequest) -> Self {
+        Response::bad_request().set_body(AnyBody::from("error"))
     }
 }
 
@@ -460,3 +488,85 @@ async fn test_h1_service_error() {
     let bytes = srv.load_body(response).await.unwrap();
     assert_eq!(bytes, Bytes::from_static(b"error"));
 }
+
+const H2_ALPN_PROTOCOL: &[u8] = b"h2";
+const HTTP1_1_ALPN_PROTOCOL: &[u8] = b"http/1.1";
+const CUSTOM_ALPN_PROTOCOL: &[u8] = b"custom";
+
+#[actix_rt::test]
+async fn test_alpn_h1() -> io::Result<()> {
+    let srv = test_server(move || {
+        let mut config = tls_config();
+        config.alpn_protocols.push(CUSTOM_ALPN_PROTOCOL.to_vec());
+        HttpService::build()
+            .h1(|_| ok::<_, Error>(Response::ok()))
+            .rustls(config)
+    })
+    .await;
+
+    assert_eq!(
+        get_negotiated_alpn_protocol(srv.addr(), CUSTOM_ALPN_PROTOCOL),
+        Some(CUSTOM_ALPN_PROTOCOL.to_vec())
+    );
+
+    let response = srv.sget("/").send().await.unwrap();
+    assert!(response.status().is_success());
+
+    Ok(())
+}
+
+#[actix_rt::test]
+async fn test_alpn_h2() -> io::Result<()> {
+    let srv = test_server(move || {
+        let mut config = tls_config();
+        config.alpn_protocols.push(CUSTOM_ALPN_PROTOCOL.to_vec());
+        HttpService::build()
+            .h2(|_| ok::<_, Error>(Response::ok()))
+            .rustls(config)
+    })
+    .await;
+
+    assert_eq!(
+        get_negotiated_alpn_protocol(srv.addr(), H2_ALPN_PROTOCOL),
+        Some(H2_ALPN_PROTOCOL.to_vec())
+    );
+    assert_eq!(
+        get_negotiated_alpn_protocol(srv.addr(), CUSTOM_ALPN_PROTOCOL),
+        Some(CUSTOM_ALPN_PROTOCOL.to_vec())
+    );
+
+    let response = srv.sget("/").send().await.unwrap();
+    assert!(response.status().is_success());
+
+    Ok(())
+}
+
+#[actix_rt::test]
+async fn test_alpn_h2_1() -> io::Result<()> {
+    let srv = test_server(move || {
+        let mut config = tls_config();
+        config.alpn_protocols.push(CUSTOM_ALPN_PROTOCOL.to_vec());
+        HttpService::build()
+            .finish(|_| ok::<_, Error>(Response::ok()))
+            .rustls(config)
+    })
+    .await;
+
+    assert_eq!(
+        get_negotiated_alpn_protocol(srv.addr(), H2_ALPN_PROTOCOL),
+        Some(H2_ALPN_PROTOCOL.to_vec())
+    );
+    assert_eq!(
+        get_negotiated_alpn_protocol(srv.addr(), HTTP1_1_ALPN_PROTOCOL),
+        Some(HTTP1_1_ALPN_PROTOCOL.to_vec())
+    );
+    assert_eq!(
+        get_negotiated_alpn_protocol(srv.addr(), CUSTOM_ALPN_PROTOCOL),
+        Some(CUSTOM_ALPN_PROTOCOL.to_vec())
+    );
+
+    let response = srv.sget("/").send().await.unwrap();
+    assert!(response.status().is_success());
+
+    Ok(())
+}
diff --git a/actix-http/tests/test_server.rs b/actix-http/tests/test_server.rs
index abfda249c..1e6d0b637 100644
--- a/actix-http/tests/test_server.rs
+++ b/actix-http/tests/test_server.rs
@@ -1,21 +1,25 @@
-use std::io::{Read, Write};
-use std::time::Duration;
-use std::{net, thread};
+use std::{
+    convert::Infallible,
+    io::{Read, Write},
+    net, thread,
+    time::Duration,
+};
 
 use actix_http::{
-    body::{Body, SizedStream},
-    http::{self, header, StatusCode},
-    Error, HttpService, KeepAlive, Request, Response,
+    body::{AnyBody, Body, SizedStream},
+    header, http, Error, HttpMessage, HttpService, KeepAlive, Request, Response,
+    StatusCode,
 };
-use actix_http::{HttpMessage, ResponseError};
 use actix_http_test::test_server;
 use actix_rt::time::sleep;
 use actix_service::fn_service;
 use actix_utils::future::{err, ok, ready};
 use bytes::Bytes;
 use derive_more::{Display, Error};
-use futures_util::stream::{once, StreamExt as _};
-use futures_util::FutureExt as _;
+use futures_util::{
+    stream::{once, StreamExt as _},
+    FutureExt as _,
+};
 use regex::Regex;
 
 #[actix_rt::test]
@@ -27,7 +31,7 @@ async fn test_h1() {
             .client_disconnect(1000)
             .h1(|req: Request| {
                 assert!(req.peer_addr().is_some());
-                ok::<_, ()>(Response::ok())
+                ok::<_, Infallible>(Response::ok())
             })
             .tcp()
     })
@@ -47,7 +51,7 @@ async fn test_h1_2() {
             .finish(|req: Request| {
                 assert!(req.peer_addr().is_some());
                 assert_eq!(req.version(), http::Version::HTTP_11);
-                ok::<_, ()>(Response::ok())
+                ok::<_, Infallible>(Response::ok())
             })
             .tcp()
     })
@@ -61,9 +65,9 @@ async fn test_h1_2() {
 #[display(fmt = "expect failed")]
 struct ExpectFailed;
 
-impl ResponseError for ExpectFailed {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::PRECONDITION_FAILED
+impl From<ExpectFailed> for Response<AnyBody> {
+    fn from(_: ExpectFailed) -> Self {
+        Response::new(StatusCode::EXPECTATION_FAILED)
     }
 }
 
@@ -78,7 +82,7 @@ async fn test_expect_continue() {
                     err(ExpectFailed)
                 }
             }))
-            .finish(|_| ok::<_, ()>(Response::ok()))
+            .finish(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -87,7 +91,7 @@ async fn test_expect_continue() {
     let _ = stream.write_all(b"GET /test HTTP/1.1\r\nexpect: 100-continue\r\n\r\n");
     let mut data = String::new();
     let _ = stream.read_to_string(&mut data);
-    assert!(data.starts_with("HTTP/1.1 412 Precondition Failed\r\ncontent-length"));
+    assert!(data.starts_with("HTTP/1.1 417 Expectation Failed\r\ncontent-length"));
 
     let mut stream = net::TcpStream::connect(srv.addr()).unwrap();
     let _ = stream.write_all(b"GET /test?yes= HTTP/1.1\r\nexpect: 100-continue\r\n\r\n");
@@ -109,7 +113,7 @@ async fn test_expect_continue_h1() {
                     }
                 })
             }))
-            .h1(fn_service(|_| ok::<_, ()>(Response::ok())))
+            .h1(fn_service(|_| ok::<_, Infallible>(Response::ok())))
             .tcp()
     })
     .await;
@@ -118,7 +122,7 @@ async fn test_expect_continue_h1() {
     let _ = stream.write_all(b"GET /test HTTP/1.1\r\nexpect: 100-continue\r\n\r\n");
     let mut data = String::new();
     let _ = stream.read_to_string(&mut data);
-    assert!(data.starts_with("HTTP/1.1 412 Precondition Failed\r\ncontent-length"));
+    assert!(data.starts_with("HTTP/1.1 417 Expectation Failed\r\ncontent-length"));
 
     let mut stream = net::TcpStream::connect(srv.addr()).unwrap();
     let _ = stream.write_all(b"GET /test?yes= HTTP/1.1\r\nexpect: 100-continue\r\n\r\n");
@@ -190,7 +194,7 @@ async fn test_slow_request() {
     let srv = test_server(|| {
         HttpService::build()
             .client_timeout(100)
-            .finish(|_| ok::<_, ()>(Response::ok()))
+            .finish(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -206,7 +210,7 @@ async fn test_slow_request() {
 async fn test_http1_malformed_request() {
     let srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok()))
+            .h1(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -222,7 +226,7 @@ async fn test_http1_malformed_request() {
 async fn test_http1_keepalive() {
     let srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok()))
+            .h1(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -244,7 +248,7 @@ async fn test_http1_keepalive_timeout() {
     let srv = test_server(|| {
         HttpService::build()
             .keep_alive(1)
-            .h1(|_| ok::<_, ()>(Response::ok()))
+            .h1(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -265,7 +269,7 @@ async fn test_http1_keepalive_timeout() {
 async fn test_http1_keepalive_close() {
     let srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok()))
+            .h1(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -286,7 +290,7 @@ async fn test_http1_keepalive_close() {
 async fn test_http10_keepalive_default_close() {
     let srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok()))
+            .h1(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -306,7 +310,7 @@ async fn test_http10_keepalive_default_close() {
 async fn test_http10_keepalive() {
     let srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok()))
+            .h1(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -334,7 +338,7 @@ async fn test_http1_keepalive_disabled() {
     let srv = test_server(|| {
         HttpService::build()
             .keep_alive(KeepAlive::Disabled)
-            .h1(|_| ok::<_, ()>(Response::ok()))
+            .h1(|_| ok::<_, Infallible>(Response::ok()))
             .tcp()
     })
     .await;
@@ -369,7 +373,7 @@ async fn test_content_length() {
                     StatusCode::OK,
                     StatusCode::NOT_FOUND,
                 ];
-                ok::<_, ()>(Response::new(statuses[indx]))
+                ok::<_, Infallible>(Response::new(statuses[indx]))
             })
             .tcp()
     })
@@ -424,7 +428,7 @@ async fn test_h1_headers() {
                         TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST TEST ",
                 ));
             }
-            ok::<_, ()>(builder.body(data.clone()))
+            ok::<_, Infallible>(builder.body(data.clone()))
         }).tcp()
     }).await;
 
@@ -462,7 +466,7 @@ const STR: &str = "Hello World Hello World Hello World Hello World Hello World \
 async fn test_h1_body() {
     let mut srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h1(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .tcp()
     })
     .await;
@@ -479,7 +483,7 @@ async fn test_h1_body() {
 async fn test_h1_head_empty() {
     let mut srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h1(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .tcp()
     })
     .await;
@@ -504,7 +508,7 @@ async fn test_h1_head_empty() {
 async fn test_h1_head_binary() {
     let mut srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h1(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .tcp()
     })
     .await;
@@ -529,7 +533,7 @@ async fn test_h1_head_binary() {
 async fn test_h1_head_binary2() {
     let srv = test_server(|| {
         HttpService::build()
-            .h1(|_| ok::<_, ()>(Response::ok().set_body(STR)))
+            .h1(|_| ok::<_, Infallible>(Response::ok().set_body(STR)))
             .tcp()
     })
     .await;
@@ -551,8 +555,8 @@ async fn test_h1_body_length() {
     let mut srv = test_server(|| {
         HttpService::build()
             .h1(|_| {
-                let body = once(ok(Bytes::from_static(STR.as_ref())));
-                ok::<_, ()>(
+                let body = once(ok::<_, Infallible>(Bytes::from_static(STR.as_ref())));
+                ok::<_, Infallible>(
                     Response::ok().set_body(SizedStream::new(STR.len() as u64, body)),
                 )
             })
@@ -574,7 +578,7 @@ async fn test_h1_body_chunked_explicit() {
         HttpService::build()
             .h1(|_| {
                 let body = once(ok::<_, Error>(Bytes::from_static(STR.as_ref())));
-                ok::<_, ()>(
+                ok::<_, Infallible>(
                     Response::build(StatusCode::OK)
                         .insert_header((header::TRANSFER_ENCODING, "chunked"))
                         .streaming(body),
@@ -609,7 +613,7 @@ async fn test_h1_body_chunked_implicit() {
         HttpService::build()
             .h1(|_| {
                 let body = once(ok::<_, Error>(Bytes::from_static(STR.as_ref())));
-                ok::<_, ()>(Response::build(StatusCode::OK).streaming(body))
+                ok::<_, Infallible>(Response::build(StatusCode::OK).streaming(body))
             })
             .tcp()
     })
@@ -638,7 +642,7 @@ async fn test_h1_response_http_error_handling() {
         HttpService::build()
             .h1(fn_service(|_| {
                 let broken_header = Bytes::from_static(b"\0\0\0");
-                ok::<_, ()>(
+                ok::<_, Infallible>(
                     Response::build(StatusCode::OK)
                         .insert_header((http::header::CONTENT_TYPE, broken_header))
                         .body(STR),
@@ -653,16 +657,19 @@ async fn test_h1_response_http_error_handling() {
 
     // read response
     let bytes = srv.load_body(response).await.unwrap();
-    assert_eq!(bytes, Bytes::from_static(b"failed to parse header value"));
+    assert_eq!(
+        bytes,
+        Bytes::from_static(b"error processing HTTP: failed to parse header value")
+    );
 }
 
 #[derive(Debug, Display, Error)]
 #[display(fmt = "error")]
 struct BadRequest;
 
-impl ResponseError for BadRequest {
-    fn status_code(&self) -> StatusCode {
-        StatusCode::BAD_REQUEST
+impl From<BadRequest> for Response<AnyBody> {
+    fn from(_: BadRequest) -> Self {
+        Response::bad_request().set_body(AnyBody::from("error"))
     }
 }
 
@@ -692,7 +699,7 @@ async fn test_h1_on_connect() {
             })
             .h1(|req: Request| {
                 assert!(req.extensions().contains::<isize>());
-                ok::<_, ()>(Response::ok())
+                ok::<_, Infallible>(Response::ok())
             })
             .tcp()
     })
diff --git a/actix-http/tests/test_ws.rs b/actix-http/tests/test_ws.rs
index b17d4211f..6d0de2316 100644
--- a/actix-http/tests/test_ws.rs
+++ b/actix-http/tests/test_ws.rs
@@ -1,11 +1,12 @@
 use std::{
     cell::Cell,
+    convert::Infallible,
     task::{Context, Poll},
 };
 
 use actix_codec::{AsyncRead, AsyncWrite, Framed};
 use actix_http::{
-    body::BodySize,
+    body::{AnyBody, BodySize},
     h1,
     ws::{self, CloseCode, Frame, Item, Message},
     Error, HttpService, Request, Response,
@@ -13,6 +14,7 @@ use actix_http::{
 use actix_http_test::test_server;
 use actix_service::{fn_factory, Service};
 use bytes::Bytes;
+use derive_more::{Display, Error, From};
 use futures_core::future::LocalBoxFuture;
 use futures_util::{SinkExt as _, StreamExt as _};
 
@@ -33,12 +35,39 @@ impl WsService {
     }
 }
 
+#[derive(Debug, Display, Error, From)]
+enum WsServiceError {
+    #[display(fmt = "http error")]
+    Http(actix_http::Error),
+
+    #[display(fmt = "ws handshake error")]
+    Ws(actix_http::ws::HandshakeError),
+
+    #[display(fmt = "io error")]
+    Io(std::io::Error),
+
+    #[display(fmt = "dispatcher error")]
+    Dispatcher,
+}
+
+impl From<WsServiceError> for Response<AnyBody> {
+    fn from(err: WsServiceError) -> Self {
+        match err {
+            WsServiceError::Http(err) => err.into(),
+            WsServiceError::Ws(err) => err.into(),
+            WsServiceError::Io(_err) => unreachable!(),
+            WsServiceError::Dispatcher => Response::internal_server_error()
+                .set_body(AnyBody::from(format!("{}", err))),
+        }
+    }
+}
+
 impl<T> Service<(Request, Framed<T, h1::Codec>)> for WsService
 where
     T: AsyncRead + AsyncWrite + Unpin + 'static,
 {
     type Response = ();
-    type Error = Error;
+    type Error = WsServiceError;
     type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
 
     fn poll_ready(&self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
@@ -56,7 +85,9 @@ where
 
             let framed = framed.replace_codec(ws::Codec::new());
 
-            ws::Dispatcher::with(framed, service).await?;
+            ws::Dispatcher::with(framed, service)
+                .await
+                .map_err(|_| WsServiceError::Dispatcher)?;
 
             Ok(())
         })
@@ -72,7 +103,7 @@ async fn service(msg: Frame) -> Result<Message, Error> {
         Frame::Binary(bin) => Message::Binary(bin),
         Frame::Continuation(item) => Message::Continuation(item),
         Frame::Close(reason) => Message::Close(reason),
-        _ => return Err(Error::from(ws::ProtocolError::BadOpCode)),
+        _ => return Err(ws::ProtocolError::BadOpCode.into()),
     };
 
     Ok(msg)
@@ -82,8 +113,10 @@ async fn service(msg: Frame) -> Result<Message, Error> {
 async fn test_simple() {
     let mut srv = test_server(|| {
         HttpService::build()
-            .upgrade(fn_factory(|| async { Ok::<_, ()>(WsService::new()) }))
-            .finish(|_| async { Ok::<_, ()>(Response::not_found()) })
+            .upgrade(fn_factory(|| async {
+                Ok::<_, Infallible>(WsService::new())
+            }))
+            .finish(|_| async { Ok::<_, Infallible>(Response::not_found()) })
             .tcp()
     })
     .await;
diff --git a/actix-multipart/CHANGES.md b/actix-multipart/CHANGES.md
index cd50305cb..0b6affa3c 100644
--- a/actix-multipart/CHANGES.md
+++ b/actix-multipart/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 0.4.0-beta.5 - 2021-06-17
+* No notable changes.
+
+
 ## 0.4.0-beta.4 - 2021-04-02
 * No notable changes.
 
diff --git a/actix-multipart/Cargo.toml b/actix-multipart/Cargo.toml
index fd9a8d529..5103407ca 100644
--- a/actix-multipart/Cargo.toml
+++ b/actix-multipart/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-multipart"
-version = "0.4.0-beta.4"
+version = "0.4.0-beta.5"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Multipart form support for Actix Web"
 readme = "README.md"
@@ -16,7 +16,7 @@ name = "actix_multipart"
 path = "src/lib.rs"
 
 [dependencies]
-actix-web = { version = "4.0.0-beta.6", default-features = false }
+actix-web = { version = "4.0.0-beta.8", default-features = false }
 actix-utils = "3.0.0"
 
 bytes = "1"
@@ -31,6 +31,6 @@ twoway = "0.2"
 
 [dev-dependencies]
 actix-rt = "2.2"
-actix-http = "3.0.0-beta.6"
+actix-http = "3.0.0-beta.8"
 tokio = { version = "1", features = ["sync"] }
 tokio-stream = "0.1"
diff --git a/actix-multipart/README.md b/actix-multipart/README.md
index 8a4279a62..78855b815 100644
--- a/actix-multipart/README.md
+++ b/actix-multipart/README.md
@@ -3,15 +3,15 @@
 > Multipart form support for Actix Web.
 
 [![crates.io](https://img.shields.io/crates/v/actix-multipart?label=latest)](https://crates.io/crates/actix-multipart)
-[![Documentation](https://docs.rs/actix-multipart/badge.svg?version=0.4.0-beta.4)](https://docs.rs/actix-multipart/0.4.0-beta.4)
+[![Documentation](https://docs.rs/actix-multipart/badge.svg?version=0.4.0-beta.5)](https://docs.rs/actix-multipart/0.4.0-beta.5)
 [![Version](https://img.shields.io/badge/rustc-1.46+-ab6000.svg)](https://blog.rust-lang.org/2020/03/12/Rust-1.46.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-multipart.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-multipart/0.4.0-beta.4/status.svg)](https://deps.rs/crate/actix-multipart/0.4.0-beta.4)
+[![dependency status](https://deps.rs/crate/actix-multipart/0.4.0-beta.5/status.svg)](https://deps.rs/crate/actix-multipart/0.4.0-beta.5)
 [![Download](https://img.shields.io/crates/d/actix-multipart.svg)](https://crates.io/crates/actix-multipart)
+[![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
 ## Documentation & Resources
 
 - [API Documentation](https://docs.rs/actix-multipart)
-- [Chat on Gitter](https://gitter.im/actix/actix-web)
 - Minimum Supported Rust Version (MSRV): 1.46.0
diff --git a/actix-test/CHANGES.md b/actix-test/CHANGES.md
index 2276fe745..fa554ba2e 100644
--- a/actix-test/CHANGES.md
+++ b/actix-test/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 0.1.0-beta.3 - 2021-06-20
+* No significant changes from `0.1.0-beta.2`.
+
+
 ## 0.1.0-beta.2 - 2021-04-17
 * No significant changes from `0.1.0-beta.1`.
 
diff --git a/actix-test/Cargo.toml b/actix-test/Cargo.toml
index 23f3650cd..b732cf744 100644
--- a/actix-test/Cargo.toml
+++ b/actix-test/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-test"
-version = "0.1.0-beta.2"
+version = "0.1.0-beta.3"
 authors = [
     "Nikolay Kim <fafhrd91@gmail.com>",
     "Rob Ede <robjtede@icloud.com>",
@@ -20,13 +20,13 @@ openssl = ["tls-openssl", "actix-http/openssl"]
 
 [dependencies]
 actix-codec = "0.4.0"
-actix-http = "3.0.0-beta.6"
+actix-http = "3.0.0-beta.8"
 actix-http-test = { version = "3.0.0-beta.4", features = [] }
 actix-service = "2.0.0"
 actix-utils = "3.0.0"
-actix-web = { version = "4.0.0-beta.6", default-features = false, features = ["cookies"] }
+actix-web = { version = "4.0.0-beta.8", default-features = false, features = ["cookies"] }
 actix-rt = "2.1"
-awc = { version = "3.0.0-beta.5", default-features = false, features = ["cookies"] }
+awc = { version = "3.0.0-beta.7", default-features = false, features = ["cookies"] }
 
 futures-core = { version = "0.3.7", default-features = false, features = ["std"] }
 futures-util = { version = "0.3.7", default-features = false, features = [] }
diff --git a/actix-test/src/lib.rs b/actix-test/src/lib.rs
index 5d85c2687..c863af44a 100644
--- a/actix-test/src/lib.rs
+++ b/actix-test/src/lib.rs
@@ -31,7 +31,7 @@ extern crate tls_openssl as openssl;
 #[cfg(feature = "rustls")]
 extern crate tls_rustls as rustls;
 
-use std::{fmt, net, sync::mpsc, thread, time};
+use std::{error::Error as StdError, fmt, net, sync::mpsc, thread, time};
 
 use actix_codec::{AsyncRead, AsyncWrite, Framed};
 pub use actix_http::test::TestBuffer;
@@ -39,7 +39,7 @@ use actix_http::{
     http::{HeaderMap, Method},
     ws, HttpService, Request, Response,
 };
-use actix_service::{map_config, IntoServiceFactory, ServiceFactory};
+use actix_service::{map_config, IntoServiceFactory, ServiceFactory, ServiceFactoryExt as _};
 use actix_web::{
     dev::{AppConfig, MessageBody, Server, Service},
     rt, web, Error,
@@ -86,7 +86,7 @@ where
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     start_with(TestServerConfig::default(), factory)
 }
@@ -126,7 +126,7 @@ where
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     let (tx, rx) = mpsc::channel();
 
@@ -153,25 +153,40 @@ where
                 HttpVer::Http1 => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .h1(map_config(factory(), move |_| app_cfg.clone()))
+                        .h1(map_config(fac, move |_| app_cfg.clone()))
                         .tcp()
                 }),
                 HttpVer::Http2 => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .h2(map_config(factory(), move |_| app_cfg.clone()))
+                        .h2(map_config(fac, move |_| app_cfg.clone()))
                         .tcp()
                 }),
                 HttpVer::Both => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .finish(map_config(factory(), move |_| app_cfg.clone()))
+                        .finish(map_config(fac, move |_| app_cfg.clone()))
                         .tcp()
                 }),
             },
@@ -180,25 +195,40 @@ where
                 HttpVer::Http1 => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .h1(map_config(factory(), move |_| app_cfg.clone()))
+                        .h1(map_config(fac, move |_| app_cfg.clone()))
                         .openssl(acceptor.clone())
                 }),
                 HttpVer::Http2 => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .h2(map_config(factory(), move |_| app_cfg.clone()))
+                        .h2(map_config(fac, move |_| app_cfg.clone()))
                         .openssl(acceptor.clone())
                 }),
                 HttpVer::Both => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .finish(map_config(factory(), move |_| app_cfg.clone()))
+                        .finish(map_config(fac, move |_| app_cfg.clone()))
                         .openssl(acceptor.clone())
                 }),
             },
@@ -207,25 +237,40 @@ where
                 HttpVer::Http1 => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .h1(map_config(factory(), move |_| app_cfg.clone()))
+                        .h1(map_config(fac, move |_| app_cfg.clone()))
                         .rustls(config.clone())
                 }),
                 HttpVer::Http2 => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .h2(map_config(factory(), move |_| app_cfg.clone()))
+                        .h2(map_config(fac, move |_| app_cfg.clone()))
                         .rustls(config.clone())
                 }),
                 HttpVer::Both => builder.listen("test", tcp, move || {
                     let app_cfg =
                         AppConfig::__priv_test_new(false, local_addr.to_string(), local_addr);
+
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
                     HttpService::build()
                         .client_timeout(timeout)
-                        .finish(map_config(factory(), move |_| app_cfg.clone()))
+                        .finish(map_config(fac, move |_| app_cfg.clone()))
                         .rustls(config.clone())
                 }),
             },
diff --git a/actix-web-actors/CHANGES.md b/actix-web-actors/CHANGES.md
index cd76b201e..bf642ef95 100644
--- a/actix-web-actors/CHANGES.md
+++ b/actix-web-actors/CHANGES.md
@@ -3,6 +3,16 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 4.0.0-beta.6 - 2021-06-26
+* Update `actix` to `0.12`. [#2277]
+
+[#2277]: https://github.com/actix/actix-web/pull/2277
+
+
+## 4.0.0-beta.5 - 2021-06-17
+* No notable changes.
+
+
 ## 4.0.0-beta.4 - 2021-04-02
 * No notable changes.
 
diff --git a/actix-web-actors/Cargo.toml b/actix-web-actors/Cargo.toml
index b653dd92a..fcb5195b8 100644
--- a/actix-web-actors/Cargo.toml
+++ b/actix-web-actors/Cargo.toml
@@ -1,13 +1,11 @@
 [package]
 name = "actix-web-actors"
-version = "4.0.0-beta.4"
+version = "4.0.0-beta.6"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Actix actors support for Actix Web"
-readme = "README.md"
 keywords = ["actix", "http", "web", "framework", "async"]
 homepage = "https://actix.rs"
-repository = "https://github.com/actix/actix-web.git"
-documentation = "https://docs.rs/actix-web-actors/"
+repository = "https://github.com/actix/actix-web"
 license = "MIT OR Apache-2.0"
 edition = "2018"
 
@@ -16,10 +14,10 @@ name = "actix_web_actors"
 path = "src/lib.rs"
 
 [dependencies]
-actix = { version = "0.11.0-beta.3", default-features = false }
+actix = { version = "0.12.0", default-features = false }
 actix-codec = "0.4.0"
-actix-http = "3.0.0-beta.6"
-actix-web = { version = "4.0.0-beta.6", default-features = false }
+actix-http = "3.0.0-beta.8"
+actix-web = { version = "4.0.0-beta.8", default-features = false }
 
 bytes = "1"
 bytestring = "1"
@@ -29,8 +27,8 @@ tokio = { version = "1", features = ["sync"] }
 
 [dev-dependencies]
 actix-rt = "2.2"
-actix-test = "0.1.0-beta.2"
+actix-test = "0.1.0-beta.3"
 
-awc = { version = "3.0.0-beta.5", default-features = false }
+awc = { version = "3.0.0-beta.7", default-features = false }
 env_logger = "0.8"
 futures-util = { version = "0.3.7", default-features = false }
diff --git a/actix-web-actors/README.md b/actix-web-actors/README.md
index 2dc779f10..5f8f78bde 100644
--- a/actix-web-actors/README.md
+++ b/actix-web-actors/README.md
@@ -3,16 +3,15 @@
 > Actix actors support for Actix Web.
 
 [![crates.io](https://img.shields.io/crates/v/actix-web-actors?label=latest)](https://crates.io/crates/actix-web-actors)
-[![Documentation](https://docs.rs/actix-web-actors/badge.svg?version=4.0.0-beta.4)](https://docs.rs/actix-web-actors/4.0.0-beta.4)
+[![Documentation](https://docs.rs/actix-web-actors/badge.svg?version=4.0.0-beta.6)](https://docs.rs/actix-web-actors/4.0.0-beta.6)
 [![Version](https://img.shields.io/badge/rustc-1.46+-ab6000.svg)](https://blog.rust-lang.org/2020/03/12/Rust-1.46.html)
 ![License](https://img.shields.io/crates/l/actix-web-actors.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-web-actors/4.0.0-beta.4/status.svg)](https://deps.rs/crate/actix-web-actors/4.0.0-beta.4)
+[![dependency status](https://deps.rs/crate/actix-web-actors/4.0.0-beta.6/status.svg)](https://deps.rs/crate/actix-web-actors/4.0.0-beta.6)
 [![Download](https://img.shields.io/crates/d/actix-web-actors.svg)](https://crates.io/crates/actix-web-actors)
-[![Join the chat at https://gitter.im/actix/actix](https://badges.gitter.im/actix/actix.svg)](https://gitter.im/actix/actix?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
 ## Documentation & Resources
 
 - [API Documentation](https://docs.rs/actix-web-actors)
-- [Chat on Gitter](https://gitter.im/actix/actix-web)
 - Minimum supported Rust version: 1.46 or later
diff --git a/actix-web-actors/src/ws.rs b/actix-web-actors/src/ws.rs
index 8c575206d..f0a53d4e0 100644
--- a/actix-web-actors/src/ws.rs
+++ b/actix-web-actors/src/ws.rs
@@ -22,10 +22,11 @@ use actix_http::{
     http::HeaderValue,
     ws::{hash_key, Codec},
 };
-use actix_web::error::{Error, PayloadError};
-use actix_web::http::{header, Method, StatusCode};
-use actix_web::HttpResponseBuilder;
-use actix_web::{HttpRequest, HttpResponse};
+use actix_web::{
+    error::{Error, PayloadError},
+    http::{header, Method, StatusCode},
+    HttpRequest, HttpResponse, HttpResponseBuilder,
+};
 use bytes::{Bytes, BytesMut};
 use bytestring::ByteString;
 use futures_core::Stream;
diff --git a/actix-web-codegen/CHANGES.md b/actix-web-codegen/CHANGES.md
index f2c9b44b5..a8a901f72 100644
--- a/actix-web-codegen/CHANGES.md
+++ b/actix-web-codegen/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 0.5.0-beta.3 - 2021-06-17
+* No notable changes.
+
+
 ## 0.5.0-beta.2 - 2021-03-09
 * Preserve doc comments when using route macros. [#2022]
 * Add `name` attribute to `route` macro. [#1934]
diff --git a/actix-web-codegen/Cargo.toml b/actix-web-codegen/Cargo.toml
index db4f8430c..4d0fd5e26 100644
--- a/actix-web-codegen/Cargo.toml
+++ b/actix-web-codegen/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web-codegen"
-version = "0.5.0-beta.2"
+version = "0.5.0-beta.3"
 description = "Routing and runtime macros for Actix Web"
 readme = "README.md"
 homepage = "https://actix.rs"
@@ -20,9 +20,9 @@ proc-macro2 = "1"
 
 [dev-dependencies]
 actix-rt = "2.2"
-actix-test = "0.1.0-beta.2"
+actix-test = "0.1.0-beta.3"
 actix-utils = "3.0.0"
-actix-web = "4.0.0-beta.6"
+actix-web = "4.0.0-beta.8"
 
 futures-core = { version = "0.3.7", default-features = false, features = ["alloc"] }
 trybuild = "1"
diff --git a/actix-web-codegen/README.md b/actix-web-codegen/README.md
index 9552d4b56..96e4cb51f 100644
--- a/actix-web-codegen/README.md
+++ b/actix-web-codegen/README.md
@@ -3,18 +3,17 @@
 > Routing and runtime macros for Actix Web.
 
 [![crates.io](https://img.shields.io/crates/v/actix-web-codegen?label=latest)](https://crates.io/crates/actix-web-codegen)
-[![Documentation](https://docs.rs/actix-web-codegen/badge.svg?version=0.5.0-beta.2)](https://docs.rs/actix-web-codegen/0.5.0-beta.2)
+[![Documentation](https://docs.rs/actix-web-codegen/badge.svg?version=0.5.0-beta.3)](https://docs.rs/actix-web-codegen/0.5.0-beta.3)
 [![Version](https://img.shields.io/badge/rustc-1.46+-ab6000.svg)](https://blog.rust-lang.org/2020/03/12/Rust-1.46.html)
 ![License](https://img.shields.io/crates/l/actix-web-codegen.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.2/status.svg)](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.2)
+[![dependency status](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.3/status.svg)](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.3)
 [![Download](https://img.shields.io/crates/d/actix-web-codegen.svg)](https://crates.io/crates/actix-web-codegen)
-[![Join the chat at https://gitter.im/actix/actix](https://badges.gitter.im/actix/actix.svg)](https://gitter.im/actix/actix?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
 ## Documentation & Resources
 
 - [API Documentation](https://docs.rs/actix-web-codegen)
-- [Chat on Gitter](https://gitter.im/actix/actix-web)
 - Minimum supported Rust version: 1.46 or later.
 
 ## Compile Testing
diff --git a/actix-web-codegen/src/lib.rs b/actix-web-codegen/src/lib.rs
index 336345014..2237f422c 100644
--- a/actix-web-codegen/src/lib.rs
+++ b/actix-web-codegen/src/lib.rs
@@ -171,27 +171,10 @@ method_macro! {
 #[proc_macro_attribute]
 pub fn main(_: TokenStream, item: TokenStream) -> TokenStream {
     use quote::quote;
-
-    let mut input = syn::parse_macro_input!(item as syn::ItemFn);
-    let attrs = &input.attrs;
-    let vis = &input.vis;
-    let sig = &mut input.sig;
-    let body = &input.block;
-
-    if sig.asyncness.is_none() {
-        return syn::Error::new_spanned(sig.fn_token, "only async fn is supported")
-            .to_compile_error()
-            .into();
-    }
-
-    sig.asyncness = None;
-
+    let input = syn::parse_macro_input!(item as syn::ItemFn);
     (quote! {
-        #(#attrs)*
-        #vis #sig {
-            actix_web::rt::System::new()
-                .block_on(async move { #body })
-        }
+        #[actix_web::rt::main(system = "::actix_web::rt::System")]
+        #input
     })
     .into()
 }
diff --git a/actix-web-codegen/src/route.rs b/actix-web-codegen/src/route.rs
index ac0b7cea1..747042527 100644
--- a/actix-web-codegen/src/route.rs
+++ b/actix-web-codegen/src/route.rs
@@ -6,7 +6,7 @@ use std::convert::TryFrom;
 use proc_macro::TokenStream;
 use proc_macro2::{Span, TokenStream as TokenStream2};
 use quote::{format_ident, quote, ToTokens, TokenStreamExt};
-use syn::{parse_macro_input, AttributeArgs, Ident, NestedMeta};
+use syn::{parse_macro_input, AttributeArgs, Ident, LitStr, NestedMeta};
 
 enum ResourceType {
     Async,
@@ -227,8 +227,7 @@ impl Route {
                 format!(
                     r#"invalid service definition, expected #[{}("<some path>")]"#,
                     method
-                        .map(|it| it.as_str())
-                        .unwrap_or("route")
+                        .map_or("route", |it| it.as_str())
                         .to_ascii_lowercase()
                 ),
             ));
@@ -298,7 +297,7 @@ impl ToTokens for Route {
         } = self;
         let resource_name = resource_name
             .as_ref()
-            .map_or_else(|| name.to_string(), |n| n.value());
+            .map_or_else(|| name.to_string(), LitStr::value);
         let method_guards = {
             let mut others = methods.iter();
             // unwrapping since length is checked to be at least one
diff --git a/awc/CHANGES.md b/awc/CHANGES.md
index b2e0ff78d..16132be1c 100644
--- a/awc/CHANGES.md
+++ b/awc/CHANGES.md
@@ -3,6 +3,17 @@
 ## Unreleased - 2021-xx-xx
 
 
+## 3.0.0-beta.7 - 2021-06-26
+### Changed
+* Change compression algorithm features flags. [#2250]
+
+[#2250]: https://github.com/actix/actix-web/pull/2250
+
+
+## 3.0.0-beta.6 - 2021-06-17
+* No significant changes since 3.0.0-beta.5.
+
+
 ## 3.0.0-beta.5 - 2021-04-17
 ### Removed
 * Deprecated methods on `ClientRequest`: `if_true`, `if_some`. [#2148]
diff --git a/awc/Cargo.toml b/awc/Cargo.toml
index c8a184513..016d3b48b 100644
--- a/awc/Cargo.toml
+++ b/awc/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "awc"
-version = "3.0.0-beta.5"
+version = "3.0.0-beta.7"
 authors = [
     "Nikolay Kim <fafhrd91@gmail.com>",
     "fakeshadow <24548779@qq.com>",
@@ -24,10 +24,10 @@ path = "src/lib.rs"
 
 [package.metadata.docs.rs]
 # features that docs.rs will build with
-features = ["openssl", "rustls", "compress", "cookies"]
+features = ["openssl", "rustls", "compress-brotli", "compress-gzip", "compress-zstd", "cookies"]
 
 [features]
-default = ["compress", "cookies"]
+default = ["compress-brotli", "compress-gzip", "compress-zstd", "cookies"]
 
 # openssl
 openssl = ["tls-openssl", "actix-http/openssl"]
@@ -35,8 +35,12 @@ openssl = ["tls-openssl", "actix-http/openssl"]
 # rustls
 rustls = ["tls-rustls", "actix-http/rustls"]
 
-# content-encoding support
-compress = ["actix-http/compress"]
+# Brotli algorithm content-encoding support
+compress-brotli = ["actix-http/compress-brotli", "__compress"]
+# Gzip and deflate algorithms content-encoding support
+compress-gzip = ["actix-http/compress-gzip", "__compress"]
+# Zstd algorithm content-encoding support
+compress-zstd = ["actix-http/compress-zstd", "__compress"]
 
 # cookie parsing and cookie jar
 cookies = ["cookie"]
@@ -44,14 +48,19 @@ cookies = ["cookie"]
 # trust-dns as dns resolver
 trust-dns = ["actix-http/trust-dns"]
 
+# Internal (PRIVATE!) features used to aid testing and cheking feature status.
+# Don't rely on these whatsoever. They may disappear at anytime.
+__compress = []
+
 [dependencies]
 actix-codec = "0.4.0"
 actix-service = "2.0.0"
-actix-http = "3.0.0-beta.6"
+actix-http = "3.0.0-beta.8"
 actix-rt = { version = "2.1", default-features = false }
 
 base64 = "0.13"
 bytes = "1"
+cfg-if = "1"
 cookie = { version = "0.15", features = ["percent-encode"], optional = true }
 derive_more = "0.99.5"
 futures-core = { version = "0.3.7", default-features = false }
@@ -68,13 +77,13 @@ tls-openssl = { version = "0.10.9", package = "openssl", optional = true }
 tls-rustls = { version = "0.19.0", package = "rustls", optional = true, features = ["dangerous_configuration"] }
 
 [dev-dependencies]
-actix-web = { version = "4.0.0-beta.6", features = ["openssl"] }
-actix-http = { version = "3.0.0-beta.6", features = ["openssl"] }
+actix-web = { version = "4.0.0-beta.8", features = ["openssl"] }
+actix-http = { version = "3.0.0-beta.8", features = ["openssl"] }
 actix-http-test = { version = "3.0.0-beta.4", features = ["openssl"] }
 actix-utils = "3.0.0"
 actix-server = "2.0.0-beta.3"
 actix-tls = { version = "3.0.0-beta.5", features = ["openssl", "rustls"] }
-actix-test = { version = "0.1.0-beta.2", features = ["openssl", "rustls"] }
+actix-test = { version = "0.1.0-beta.3", features = ["openssl", "rustls"] }
 
 brotli2 = "0.3.2"
 env_logger = "0.8"
diff --git a/awc/README.md b/awc/README.md
index a836a2497..dd08c6e10 100644
--- a/awc/README.md
+++ b/awc/README.md
@@ -3,16 +3,15 @@
 > Async HTTP and WebSocket client library.
 
 [![crates.io](https://img.shields.io/crates/v/awc?label=latest)](https://crates.io/crates/awc)
-[![Documentation](https://docs.rs/awc/badge.svg?version=3.0.0-beta.4)](https://docs.rs/awc/3.0.0-beta.4)
+[![Documentation](https://docs.rs/awc/badge.svg?version=3.0.0-beta.7)](https://docs.rs/awc/3.0.0-beta.7)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/awc)
-[![Dependency Status](https://deps.rs/crate/awc/3.0.0-beta.4/status.svg)](https://deps.rs/crate/awc/3.0.0-beta.4)
-[![Join the chat at https://gitter.im/actix/actix-web](https://badges.gitter.im/actix/actix-web.svg)](https://gitter.im/actix/actix-web?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Dependency Status](https://deps.rs/crate/awc/3.0.0-beta.7/status.svg)](https://deps.rs/crate/awc/3.0.0-beta.7)
+[![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)
 
 ## Documentation & Resources
 
 - [API Documentation](https://docs.rs/awc)
 - [Example Project](https://github.com/actix/examples/tree/HEAD/security/awc_https)
-- [Chat on Gitter](https://gitter.im/actix/actix-web)
 - Minimum Supported Rust Version (MSRV): 1.46.0
 
 ## Example
diff --git a/awc/examples/client.rs b/awc/examples/client.rs
index b9574590d..653cb226f 100644
--- a/awc/examples/client.rs
+++ b/awc/examples/client.rs
@@ -1,18 +1,20 @@
-use actix_http::Error;
+use std::error::Error as StdError;
 
 #[actix_web::main]
-async fn main() -> Result<(), Error> {
-    std::env::set_var("RUST_LOG", "actix_http=trace");
+async fn main() -> Result<(), Box<dyn StdError>> {
+    std::env::set_var("RUST_LOG", "client=trace,awc=trace,actix_http=trace");
     env_logger::init();
 
     let client = awc::Client::new();
 
     // Create request builder, configure request and send
-    let mut response = client
+    let request = client
         .get("https://www.rust-lang.org/")
-        .append_header(("User-Agent", "Actix-web"))
-        .send()
-        .await?;
+        .append_header(("User-Agent", "Actix-web"));
+
+    println!("Request: {:?}", request);
+
+    let mut response = request.send().await?;
 
     // server http response
     println!("Response: {:?}", response);
diff --git a/awc/src/error.rs b/awc/src/error.rs
index b715f6213..c83c5ebbf 100644
--- a/awc/src/error.rs
+++ b/awc/src/error.rs
@@ -6,7 +6,6 @@ pub use actix_http::http::Error as HttpError;
 pub use actix_http::ws::HandshakeError as WsHandshakeError;
 pub use actix_http::ws::ProtocolError as WsProtocolError;
 
-use actix_http::ResponseError;
 use serde_json::error::Error as JsonError;
 
 use actix_http::http::{header::HeaderValue, StatusCode};
@@ -77,6 +76,3 @@ pub enum JsonPayloadError {
 }
 
 impl std::error::Error for JsonPayloadError {}
-
-/// Return `InternalServerError` for `JsonPayloadError`
-impl ResponseError for JsonPayloadError {}
diff --git a/awc/src/frozen.rs b/awc/src/frozen.rs
index 5fe8edb19..cb8c0f1bf 100644
--- a/awc/src/frozen.rs
+++ b/awc/src/frozen.rs
@@ -1,21 +1,21 @@
-use std::convert::TryFrom;
-use std::net;
-use std::rc::Rc;
-use std::time::Duration;
+use std::{convert::TryFrom, error::Error as StdError, net, rc::Rc, time::Duration};
 
 use bytes::Bytes;
 use futures_core::Stream;
 use serde::Serialize;
 
-use actix_http::body::Body;
-use actix_http::http::header::IntoHeaderValue;
-use actix_http::http::{Error as HttpError, HeaderMap, HeaderName, Method, Uri};
-use actix_http::{Error, RequestHead};
+use actix_http::{
+    body::Body,
+    http::{header::IntoHeaderValue, Error as HttpError, HeaderMap, HeaderName, Method, Uri},
+    RequestHead,
+};
 
-use crate::sender::{RequestSender, SendClientRequest};
-use crate::ClientConfig;
+use crate::{
+    sender::{RequestSender, SendClientRequest},
+    ClientConfig,
+};
 
-/// `FrozenClientRequest` struct represents clonable client request.
+/// `FrozenClientRequest` struct represents cloneable client request.
 /// It could be used to send same request multiple times.
 #[derive(Clone)]
 pub struct FrozenClientRequest {
@@ -82,7 +82,7 @@ impl FrozenClientRequest {
     pub fn send_stream<S, E>(&self, stream: S) -> SendClientRequest
     where
         S: Stream<Item = Result<Bytes, E>> + Unpin + 'static,
-        E: Into<Error> + 'static,
+        E: Into<Box<dyn StdError>> + 'static,
     {
         RequestSender::Rc(self.head.clone(), None).send_stream(
             self.addr,
@@ -207,7 +207,7 @@ impl FrozenSendBuilder {
     pub fn send_stream<S, E>(self, stream: S) -> SendClientRequest
     where
         S: Stream<Item = Result<Bytes, E>> + Unpin + 'static,
-        E: Into<Error> + 'static,
+        E: Into<Box<dyn StdError>> + 'static,
     {
         if let Some(e) = self.err {
             return e.into();
diff --git a/awc/src/lib.rs b/awc/src/lib.rs
index 562d6ee7f..c0290ddcf 100644
--- a/awc/src/lib.rs
+++ b/awc/src/lib.rs
@@ -1,7 +1,6 @@
 //! `awc` is a HTTP and WebSocket client library built on the Actix ecosystem.
 //!
-//! ## Making a GET request
-//!
+//! # Making a GET request
 //! ```no_run
 //! # #[actix_rt::main]
 //! # async fn main() -> Result<(), awc::error::SendRequestError> {
@@ -16,10 +15,8 @@
 //! # }
 //! ```
 //!
-//! ## Making POST requests
-//!
-//! ### Raw body contents
-//!
+//! # Making POST requests
+//! ## Raw body contents
 //! ```no_run
 //! # #[actix_rt::main]
 //! # async fn main() -> Result<(), awc::error::SendRequestError> {
@@ -31,8 +28,7 @@
 //! # }
 //! ```
 //!
-//! ### Forms
-//!
+//! ## Forms
 //! ```no_run
 //! # #[actix_rt::main]
 //! # async fn main() -> Result<(), awc::error::SendRequestError> {
@@ -46,8 +42,7 @@
 //! # }
 //! ```
 //!
-//! ### JSON
-//!
+//! ## JSON
 //! ```no_run
 //! # #[actix_rt::main]
 //! # async fn main() -> Result<(), awc::error::SendRequestError> {
@@ -64,8 +59,24 @@
 //! # }
 //! ```
 //!
-//! ## WebSocket support
+//! # Response Compression
+//! All [official][iana-encodings] and common content encoding codecs are supported, optionally.
 //!
+//! The `Accept-Encoding` header will automatically be populated with enabled codecs and added to
+//! outgoing requests, allowing servers to select their `Content-Encoding` accordingly.
+//!
+//! Feature flags enable these codecs according to the table below. By default, all `compress-*`
+//! features are enabled.
+//!
+//! | Feature           | Codecs        |
+//! | ----------------- | ------------- |
+//! | `compress-brotli` | brotli        |
+//! | `compress-gzip`   | gzip, deflate |
+//! | `compress-zstd`   | zstd          |
+//!
+//! [iana-encodings]: https://www.iana.org/assignments/http-parameters/http-parameters.xhtml#content-coding
+//!
+//! # WebSocket support
 //! ```no_run
 //! # #[actix_rt::main]
 //! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -128,8 +139,10 @@ pub use self::sender::SendClientRequest;
 
 /// An asynchronous HTTP and WebSocket client.
 ///
-/// ## Examples
+/// You should take care to create, at most, one `Client` per thread. Otherwise, expect higher CPU
+/// and memory usage.
 ///
+/// # Examples
 /// ```
 /// use awc::Client;
 ///
@@ -137,10 +150,10 @@ pub use self::sender::SendClientRequest;
 /// async fn main() {
 ///     let mut client = Client::default();
 ///
-///     let res = client.get("http://www.rust-lang.org") // <- Create request builder
-///         .insert_header(("User-Agent", "Actix-web"))
-///         .send()                             // <- Send HTTP request
-///         .await;                             // <- send request and wait for response
+///     let res = client.get("http://www.rust-lang.org")
+///         .insert_header(("User-Agent", "my-app/1.2"))
+///         .send()
+///         .await;
 ///
 ///      println!("Response: {:?}", res);
 /// }
diff --git a/awc/src/request.rs b/awc/src/request.rs
index 483524102..812c76318 100644
--- a/awc/src/request.rs
+++ b/awc/src/request.rs
@@ -1,30 +1,26 @@
-use std::convert::TryFrom;
-use std::rc::Rc;
-use std::time::Duration;
-use std::{fmt, net};
+use std::{convert::TryFrom, error::Error as StdError, fmt, net, rc::Rc, time::Duration};
 
 use bytes::Bytes;
 use futures_core::Stream;
 use serde::Serialize;
 
-use actix_http::body::Body;
-use actix_http::http::header::{self, IntoHeaderPair};
-use actix_http::http::{
-    uri, ConnectionType, Error as HttpError, HeaderMap, HeaderValue, Method, Uri, Version,
+use actix_http::{
+    body::Body,
+    http::{
+        header::{self, IntoHeaderPair},
+        ConnectionType, Error as HttpError, HeaderMap, HeaderValue, Method, Uri, Version,
+    },
+    RequestHead,
 };
-use actix_http::{Error, RequestHead};
 
 #[cfg(feature = "cookies")]
 use crate::cookie::{Cookie, CookieJar};
-use crate::error::{FreezeRequestError, InvalidUrl};
-use crate::frozen::FrozenClientRequest;
-use crate::sender::{PrepForSendingError, RequestSender, SendClientRequest};
-use crate::ClientConfig;
-
-#[cfg(feature = "compress")]
-const HTTPS_ENCODING: &str = "br, gzip, deflate";
-#[cfg(not(feature = "compress"))]
-const HTTPS_ENCODING: &str = "br";
+use crate::{
+    error::{FreezeRequestError, InvalidUrl},
+    frozen::FrozenClientRequest,
+    sender::{PrepForSendingError, RequestSender, SendClientRequest},
+    ClientConfig,
+};
 
 /// An HTTP Client request builder
 ///
@@ -408,7 +404,7 @@ impl ClientRequest {
     pub fn send_stream<S, E>(self, stream: S) -> SendClientRequest
     where
         S: Stream<Item = Result<Bytes, E>> + Unpin + 'static,
-        E: Into<Error> + 'static,
+        E: Into<Box<dyn StdError>> + 'static,
     {
         let slf = match self.prep_for_sending() {
             Ok(slf) => slf,
@@ -479,22 +475,44 @@ impl ClientRequest {
 
         let mut slf = self;
 
+        // Set Accept-Encoding HTTP header depending on enabled feature.
+        // If decompress is not ask, then we are not able to find which encoding is
+        // supported, so we cannot guess Accept-Encoding HTTP header.
         if slf.response_decompress {
-            let https = slf
-                .head
-                .uri
-                .scheme()
-                .map(|s| s == &uri::Scheme::HTTPS)
-                .unwrap_or(true);
+            // Set Accept-Encoding with compression algorithm awc is built with.
+            #[allow(clippy::vec_init_then_push)]
+            #[cfg(feature = "__compress")]
+            let accept_encoding = {
+                let mut encoding = vec![];
 
-            if https {
-                slf = slf.insert_header_if_none((header::ACCEPT_ENCODING, HTTPS_ENCODING));
-            } else {
-                #[cfg(feature = "compress")]
+                #[cfg(feature = "compress-brotli")]
                 {
-                    slf = slf.insert_header_if_none((header::ACCEPT_ENCODING, "gzip, deflate"));
+                    encoding.push("br");
                 }
+
+                #[cfg(feature = "compress-gzip")]
+                {
+                    encoding.push("gzip");
+                    encoding.push("deflate");
+                }
+
+                #[cfg(feature = "compress-zstd")]
+                encoding.push("zstd");
+
+                assert!(
+                    !encoding.is_empty(),
+                    "encoding can not be empty unless __compress feature has been explicitly enabled"
+                );
+
+                encoding.join(", ")
             };
+
+            // Otherwise tell the server, we do not support any compression algorithm.
+            // So we clearly indicate that we do want identity encoding.
+            #[cfg(not(feature = "__compress"))]
+            let accept_encoding = "identity";
+
+            slf = slf.insert_header_if_none((header::ACCEPT_ENCODING, accept_encoding));
         }
 
         Ok(slf)
diff --git a/awc/src/sender.rs b/awc/src/sender.rs
index 0e63be221..c0639606e 100644
--- a/awc/src/sender.rs
+++ b/awc/src/sender.rs
@@ -1,6 +1,7 @@
 use std::{
+    error::Error as StdError,
     future::Future,
-    io, net,
+    net,
     pin::Pin,
     rc::Rc,
     task::{Context, Poll},
@@ -21,25 +22,33 @@ use derive_more::From;
 use futures_core::Stream;
 use serde::Serialize;
 
-#[cfg(feature = "compress")]
+#[cfg(feature = "__compress")]
 use actix_http::{encoding::Decoder, http::header::ContentEncoding, Payload, PayloadStream};
 
-use crate::connect::{ConnectRequest, ConnectResponse};
-use crate::error::{FreezeRequestError, InvalidUrl, SendRequestError};
-use crate::response::ClientResponse;
-use crate::ClientConfig;
+use crate::{
+    error::{FreezeRequestError, InvalidUrl, SendRequestError},
+    ClientConfig, ClientResponse, ConnectRequest, ConnectResponse,
+};
 
 #[derive(Debug, From)]
 pub(crate) enum PrepForSendingError {
     Url(InvalidUrl),
     Http(HttpError),
+    Json(serde_json::Error),
+    Form(serde_urlencoded::ser::Error),
 }
 
 impl From<PrepForSendingError> for FreezeRequestError {
     fn from(err: PrepForSendingError) -> FreezeRequestError {
         match err {
-            PrepForSendingError::Url(e) => FreezeRequestError::Url(e),
-            PrepForSendingError::Http(e) => FreezeRequestError::Http(e),
+            PrepForSendingError::Url(err) => FreezeRequestError::Url(err),
+            PrepForSendingError::Http(err) => FreezeRequestError::Http(err),
+            PrepForSendingError::Json(err) => {
+                FreezeRequestError::Custom(Box::new(err), Box::new("json serialization error"))
+            }
+            PrepForSendingError::Form(err) => {
+                FreezeRequestError::Custom(Box::new(err), Box::new("form serialization error"))
+            }
         }
     }
 }
@@ -49,6 +58,12 @@ impl From<PrepForSendingError> for SendRequestError {
         match err {
             PrepForSendingError::Url(e) => SendRequestError::Url(e),
             PrepForSendingError::Http(e) => SendRequestError::Http(e),
+            PrepForSendingError::Json(err) => {
+                SendRequestError::Custom(Box::new(err), Box::new("json serialization error"))
+            }
+            PrepForSendingError::Form(err) => {
+                SendRequestError::Custom(Box::new(err), Box::new("form serialization error"))
+            }
         }
     }
 }
@@ -76,7 +91,7 @@ impl SendClientRequest {
     }
 }
 
-#[cfg(feature = "compress")]
+#[cfg(feature = "__compress")]
 impl Future for SendClientRequest {
     type Output = Result<ClientResponse<Decoder<Payload<PayloadStream>>>, SendRequestError>;
 
@@ -116,7 +131,7 @@ impl Future for SendClientRequest {
     }
 }
 
-#[cfg(not(feature = "compress"))]
+#[cfg(not(feature = "__compress"))]
 impl Future for SendClientRequest {
     type Output = Result<ClientResponse, SendRequestError>;
 
@@ -209,8 +224,7 @@ impl RequestSender {
     ) -> SendClientRequest {
         let body = match serde_json::to_string(value) {
             Ok(body) => body,
-            // TODO: own error type
-            Err(e) => return Error::from(io::Error::new(io::ErrorKind::Other, e)).into(),
+            Err(err) => return PrepForSendingError::Json(err).into(),
         };
 
         if let Err(e) = self.set_header_if_none(header::CONTENT_TYPE, "application/json") {
@@ -236,8 +250,7 @@ impl RequestSender {
     ) -> SendClientRequest {
         let body = match serde_urlencoded::to_string(value) {
             Ok(body) => body,
-            // TODO: own error type
-            Err(e) => return Error::from(io::Error::new(io::ErrorKind::Other, e)).into(),
+            Err(err) => return PrepForSendingError::Form(err).into(),
         };
 
         // set content-type
@@ -266,7 +279,7 @@ impl RequestSender {
     ) -> SendClientRequest
     where
         S: Stream<Item = Result<Bytes, E>> + Unpin + 'static,
-        E: Into<Error> + 'static,
+        E: Into<Box<dyn StdError>> + 'static,
     {
         self.send_body(
             addr,
diff --git a/awc/src/ws.rs b/awc/src/ws.rs
index 34b71f052..2fe36399c 100644
--- a/awc/src/ws.rs
+++ b/awc/src/ws.rs
@@ -517,7 +517,7 @@ mod tests {
             "test-origin"
         );
         assert_eq!(req.max_size, 100);
-        assert_eq!(req.server_mode, true);
+        assert!(req.server_mode);
         assert_eq!(req.protocols, Some("v1,v2".to_string()));
         assert_eq!(
             req.head.headers.get(header::CONTENT_TYPE).unwrap(),
diff --git a/benches/responder.rs b/benches/responder.rs
index 0dfc8cd18..5d0b98d5f 100644
--- a/benches/responder.rs
+++ b/benches/responder.rs
@@ -1,6 +1,5 @@
 use std::{future::Future, time::Instant};
 
-use actix_http::Response;
 use actix_utils::future::{ready, Ready};
 use actix_web::http::StatusCode;
 use actix_web::test::TestRequest;
@@ -24,11 +23,11 @@ struct StringResponder(String);
 
 impl FutureResponder for StringResponder {
     type Error = Error;
-    type Future = Ready<Result<Response, Self::Error>>;
+    type Future = Ready<Result<HttpResponse, Self::Error>>;
 
     fn future_respond_to(self, _: &HttpRequest) -> Self::Future {
         // this is default builder for string response in both new and old responder trait.
-        ready(Ok(Response::build(StatusCode::OK)
+        ready(Ok(HttpResponse::build(StatusCode::OK)
             .content_type("text/plain; charset=utf-8")
             .body(self.0)))
     }
@@ -37,7 +36,7 @@ impl FutureResponder for StringResponder {
 impl<T> FutureResponder for OptionResponder<T>
 where
     T: FutureResponder,
-    T::Future: Future<Output = Result<Response, Error>>,
+    T::Future: Future<Output = Result<HttpResponse, Error>>,
 {
     type Error = Error;
     type Future = Either<T::Future, Ready<Result<HttpResponse, Self::Error>>>;
@@ -52,7 +51,7 @@ where
 
 impl Responder for StringResponder {
     fn respond_to(self, _: &HttpRequest) -> HttpResponse {
-        Response::build(StatusCode::OK)
+        HttpResponse::build(StatusCode::OK)
             .content_type("text/plain; charset=utf-8")
             .body(self.0)
     }
@@ -62,7 +61,7 @@ impl<T: Responder> Responder for OptionResponder<T> {
     fn respond_to(self, req: &HttpRequest) -> HttpResponse {
         match self.0 {
             Some(t) => t.respond_to(req),
-            None => Response::from_error(error::ErrorInternalServerError("err")),
+            None => HttpResponse::from_error(error::ErrorInternalServerError("err")),
         }
     }
 }
diff --git a/benches/service.rs b/benches/service.rs
index 30708477d..87e51f170 100644
--- a/benches/service.rs
+++ b/benches/service.rs
@@ -51,9 +51,8 @@ where
                     fut.await.unwrap();
                 }
             });
-            let elapsed = start.elapsed();
             // check that at least first request succeeded
-            elapsed
+            start.elapsed()
         })
     });
 }
@@ -93,9 +92,8 @@ fn async_web_service(c: &mut Criterion) {
                     fut.await.unwrap();
                 }
             });
-            let elapsed = start.elapsed();
             // check that at least first request succeeded
-            elapsed
+            start.elapsed()
         })
     });
 }
diff --git a/src/app.rs b/src/app.rs
index 357d45eeb..5cff20568 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -43,13 +43,14 @@ impl App<AppEntry, Body> {
     /// Create application builder. Application can be configured with a builder-like pattern.
     #[allow(clippy::new_without_default)]
     pub fn new() -> Self {
-        let fref = Rc::new(RefCell::new(None));
+        let factory_ref = Rc::new(RefCell::new(None));
+
         App {
-            endpoint: AppEntry::new(fref.clone()),
+            endpoint: AppEntry::new(factory_ref.clone()),
             data_factories: Vec::new(),
             services: Vec::new(),
             default: None,
-            factory_ref: fref,
+            factory_ref,
             external: Vec::new(),
             extensions: Extensions::new(),
             _phantom: PhantomData,
@@ -68,43 +69,83 @@ where
         InitError = (),
     >,
 {
-    /// Set application data. Application data could be accessed
-    /// by using `Data<T>` extractor where `T` is data type.
+    /// Set application (root level) data.
     ///
-    /// **Note**: HTTP server accepts an application factory rather than
-    /// an application instance. Http server constructs an application
-    /// instance for each thread, thus application data must be constructed
-    /// multiple times. If you want to share data between different
-    /// threads, a shared object should be used, e.g. `Arc`. Internally `Data` type
-    /// uses `Arc` so data could be created outside of app factory and clones could
-    /// be stored via `App::app_data()` method.
+    /// Application data stored with `App::app_data()` method is available through the
+    /// [`HttpRequest::app_data`](crate::HttpRequest::app_data) method at runtime.
+    ///
+    /// # [`Data<T>`]
+    /// Any [`Data<T>`] type added here can utilize it's extractor implementation in handlers.
+    /// Types not wrapped in `Data<T>` cannot use this extractor. See [its docs](Data<T>) for more
+    /// about its usage and patterns.
     ///
     /// ```
     /// use std::cell::Cell;
-    /// use actix_web::{web, App, HttpResponse, Responder};
+    /// use actix_web::{web, App, HttpRequest, HttpResponse, Responder};
     ///
     /// struct MyData {
-    ///     counter: Cell<usize>,
+    ///     count: std::cell::Cell<usize>,
     /// }
     ///
-    /// async fn index(data: web::Data<MyData>) -> impl Responder {
-    ///     data.counter.set(data.counter.get() + 1);
-    ///     HttpResponse::Ok()
+    /// async fn handler(req: HttpRequest, counter: web::Data<MyData>) -> impl Responder {
+    ///     // note this cannot use the Data<T> extractor because it was not added with it
+    ///     let incr = *req.app_data::<usize>().unwrap();
+    ///     assert_eq!(incr, 3);
+    ///
+    ///     // update counter using other value from app data
+    ///     counter.count.set(counter.count.get() + incr);
+    ///
+    ///     HttpResponse::Ok().body(counter.count.get().to_string())
     /// }
     ///
-    /// let app = App::new()
-    ///     .data(MyData{ counter: Cell::new(0) })
-    ///     .service(
-    ///         web::resource("/index.html").route(
-    ///             web::get().to(index)));
+    /// let app = App::new().service(
+    ///     web::resource("/")
+    ///         .app_data(3usize)
+    ///         .app_data(web::Data::new(MyData { count: Default::default() }))
+    ///         .route(web::get().to(handler))
+    /// );
     /// ```
+    ///
+    /// # Shared Mutable State
+    /// [`HttpServer::new`](crate::HttpServer::new) accepts an application factory rather than an
+    /// application instance; the factory closure is called on each worker thread independently.
+    /// Therefore, if you want to share a data object between different workers, a shareable object
+    /// needs to be created first, outside the `HttpServer::new` closure and cloned into it.
+    /// [`Data<T>`] is an example of such a sharable object.
+    ///
+    /// ```ignore
+    /// let counter = web::Data::new(AppStateWithCounter {
+    ///     counter: Mutex::new(0),
+    /// });
+    ///
+    /// HttpServer::new(move || {
+    ///     // move counter object into the closure and clone for each worker
+    ///
+    ///     App::new()
+    ///         .app_data(counter.clone())
+    ///         .route("/", web::get().to(handler))
+    /// })
+    /// ```
+    pub fn app_data<U: 'static>(mut self, ext: U) -> Self {
+        self.extensions.insert(ext);
+        self
+    }
+
+    /// Add application (root) data after wrapping in `Data<T>`.
+    ///
+    /// Deprecated in favor of [`app_data`](Self::app_data).
+    #[deprecated(since = "4.0.0", note = "Use `.app_data(Data::new(val))` instead.")]
     pub fn data<U: 'static>(self, data: U) -> Self {
         self.app_data(Data::new(data))
     }
 
-    /// Set application data factory. This function is
-    /// similar to `.data()` but it accepts data factory. Data object get
-    /// constructed asynchronously during application initialization.
+    /// Add application data factory. This function is similar to `.data()` but it accepts a
+    /// "data factory". Data values are constructed asynchronously during application
+    /// initialization, before the server starts accepting requests.
+    #[deprecated(
+        since = "4.0.0",
+        note = "Construct data value before starting server and use `.app_data(Data::new(val))` instead."
+    )]
     pub fn data_factory<F, Out, D, E>(mut self, data: F) -> Self
     where
         F: Fn() -> Out + 'static,
@@ -133,18 +174,6 @@ where
         self
     }
 
-    /// Set application level arbitrary data item.
-    ///
-    /// Application data stored with `App::app_data()` method is available
-    /// via `HttpRequest::app_data()` method at runtime.
-    ///
-    /// This method could be used for storing `Data<T>` as well, in that case
-    /// data could be accessed by using `Data<T>` extractor.
-    pub fn app_data<U: 'static>(mut self, ext: U) -> Self {
-        self.extensions.insert(ext);
-        self
-    }
-
     /// Run external configuration as part of the application building
     /// process
     ///
@@ -518,6 +547,8 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::CREATED);
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_data_factory() {
         let srv = init_service(
@@ -541,6 +572,8 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_data_factory_errors() {
         let srv = try_init_service(
diff --git a/src/app_service.rs b/src/app_service.rs
index ca6f36202..3c1b78474 100644
--- a/src/app_service.rs
+++ b/src/app_service.rs
@@ -1,22 +1,22 @@
-use std::cell::RefCell;
-use std::rc::Rc;
+use std::{cell::RefCell, mem, rc::Rc};
 
 use actix_http::{Extensions, Request};
 use actix_router::{Path, ResourceDef, Router, Url};
-use actix_service::boxed::{self, BoxService, BoxServiceFactory};
-use actix_service::{fn_service, Service, ServiceFactory};
+use actix_service::{
+    boxed::{self, BoxService, BoxServiceFactory},
+    fn_service, Service, ServiceFactory,
+};
 use futures_core::future::LocalBoxFuture;
 use futures_util::future::join_all;
 
-use crate::data::FnDataFactory;
-use crate::error::Error;
-use crate::guard::Guard;
-use crate::request::{HttpRequest, HttpRequestPool};
-use crate::rmap::ResourceMap;
-use crate::service::{AppServiceFactory, ServiceRequest, ServiceResponse};
 use crate::{
     config::{AppConfig, AppService},
-    HttpResponse,
+    data::FnDataFactory,
+    guard::Guard,
+    request::{HttpRequest, HttpRequestPool},
+    rmap::ResourceMap,
+    service::{AppServiceFactory, ServiceRequest, ServiceResponse},
+    Error, HttpResponse,
 };
 
 type Guards = Vec<Box<dyn Guard>>;
@@ -75,7 +75,7 @@ where
         let mut config = AppService::new(config, default.clone());
 
         // register services
-        std::mem::take(&mut *self.services.borrow_mut())
+        mem::take(&mut *self.services.borrow_mut())
             .into_iter()
             .for_each(|mut srv| srv.register(&mut config));
 
@@ -98,7 +98,7 @@ where
         });
 
         // external resources
-        for mut rdef in std::mem::take(&mut *self.external.borrow_mut()) {
+        for mut rdef in mem::take(&mut *self.external.borrow_mut()) {
             rmap.add(&mut rdef, None);
         }
 
@@ -131,9 +131,9 @@ where
             let service = endpoint_fut.await?;
 
             // populate app data container from (async) data factories.
-            async_data_factories.iter().for_each(|factory| {
+            for factory in &async_data_factories {
                 factory.create(&mut app_data);
-            });
+            }
 
             Ok(AppInitService {
                 service,
@@ -144,7 +144,9 @@ where
     }
 }
 
-/// Service that takes a [`Request`] and delegates to a service that take a [`ServiceRequest`].
+/// The [`Service`] that is passed to `actix-http`'s server builder.
+///
+/// Wraps a service receiving a [`ServiceRequest`] into one receiving a [`Request`].
 pub struct AppInitService<T, B>
 where
     T: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
@@ -275,6 +277,7 @@ impl ServiceFactory<ServiceRequest> for AppRoutingFactory {
     }
 }
 
+/// The Actix Web router default entry point.
 pub struct AppRouting {
     router: Router<HttpService, Guards>,
     default: HttpService,
@@ -349,6 +352,8 @@ mod tests {
         }
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_drop_data() {
         let data = Arc::new(AtomicBool::new(false));
diff --git a/src/config.rs b/src/config.rs
index 4bd76f2b7..b072ace16 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -62,6 +62,8 @@ impl AppService {
         (self.config, self.services)
     }
 
+    /// Clones inner config and default service, returning new `AppService` with empty service list
+    /// marked as non-root.
     pub(crate) fn clone_config(&self) -> Self {
         AppService {
             config: self.config.clone(),
@@ -71,12 +73,12 @@ impl AppService {
         }
     }
 
-    /// Service configuration
+    /// Returns reference to configuration.
     pub fn config(&self) -> &AppConfig {
         &self.config
     }
 
-    /// Default resource
+    /// Returns default handler factory.
     pub fn default_service(&self) -> Rc<HttpNewService> {
         self.default.clone()
     }
@@ -92,9 +94,9 @@ impl AppService {
         F: IntoServiceFactory<S, ServiceRequest>,
         S: ServiceFactory<
                 ServiceRequest,
-                Config = (),
                 Response = ServiceResponse,
                 Error = Error,
+                Config = (),
                 InitError = (),
             > + 'static,
     {
@@ -116,6 +118,7 @@ impl AppConfig {
         AppConfig { secure, host, addr }
     }
 
+    /// Needed in actix-test crate. Semver exempt.
     #[doc(hidden)]
     pub fn __priv_test_new(secure: bool, host: String, addr: SocketAddr) -> Self {
         AppConfig::new(secure, host, addr)
@@ -141,6 +144,11 @@ impl AppConfig {
     pub fn local_addr(&self) -> SocketAddr {
         self.addr
     }
+
+    #[cfg(test)]
+    pub(crate) fn set_host(&mut self, host: &str) {
+        self.host = host.to_owned();
+    }
 }
 
 impl Default for AppConfig {
@@ -191,6 +199,7 @@ impl ServiceConfig {
     /// Add shared app data item.
     ///
     /// Counterpart to [`App::data()`](crate::App::data).
+    #[deprecated(since = "4.0.0", note = "Use `.app_data(Data::new(val))` instead.")]
     pub fn data<U: 'static>(&mut self, data: U) -> &mut Self {
         self.app_data(Data::new(data));
         self
@@ -256,6 +265,8 @@ mod tests {
     use crate::test::{call_service, init_service, read_body, TestRequest};
     use crate::{web, App, HttpRequest, HttpResponse};
 
+    // allow deprecated `ServiceConfig::data`
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_data() {
         let cfg = |cfg: &mut ServiceConfig| {
diff --git a/src/data.rs b/src/data.rs
index 7bb0758c6..9d4fe0840 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -1,12 +1,13 @@
 use std::{any::type_name, ops::Deref, sync::Arc};
 
-use actix_http::{error::Error, Extensions};
+use actix_http::Extensions;
 use actix_utils::future::{err, ok, Ready};
 use futures_core::future::LocalBoxFuture;
 use serde::Serialize;
 
 use crate::{
     dev::Payload, error::ErrorInternalServerError, extract::FromRequest, request::HttpRequest,
+    Error,
 };
 
 /// Data factory.
@@ -35,6 +36,11 @@ pub(crate) type FnDataFactory =
 /// If route data is not set for a handler, using `Data<T>` extractor would cause *Internal
 /// Server Error* response.
 ///
+// TODO: document `dyn T` functionality through converting an Arc
+// TODO: note equivalence of req.app_data<Data<T>> and Data<T> extractor
+// TODO: note that data must be inserted using Data<T> in order to extract it
+///
+/// # Examples
 /// ```
 /// use std::sync::Mutex;
 /// use actix_web::{web, App, HttpResponse, Responder};
@@ -152,6 +158,8 @@ mod tests {
         web, App, HttpResponse,
     };
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_data_extractor() {
         let srv = init_service(App::new().data("TEST".to_string()).service(
@@ -219,6 +227,8 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_route_data_extractor() {
         let srv = init_service(
@@ -248,6 +258,8 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::INTERNAL_SERVER_ERROR);
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_override_data() {
         let srv =
diff --git a/src/dev.rs b/src/dev.rs
new file mode 100644
index 000000000..a656604e3
--- /dev/null
+++ b/src/dev.rs
@@ -0,0 +1,102 @@
+//! Lower level `actix-web` types.
+//!
+//! Most users will not have to interact with the types in this module,
+//! but it is useful as a glob import for those writing middleware, developing libraries,
+//! or interacting with the service API directly:
+//!
+//! ```
+//! # #![allow(unused_imports)]
+//! use actix_web::dev::*;
+//! ```
+
+pub use crate::config::{AppConfig, AppService};
+#[doc(hidden)]
+pub use crate::handler::Handler;
+pub use crate::info::{ConnectionInfo, PeerAddr};
+pub use crate::rmap::ResourceMap;
+pub use crate::service::{HttpServiceFactory, ServiceRequest, ServiceResponse, WebService};
+
+pub use crate::types::form::UrlEncoded;
+pub use crate::types::json::JsonBody;
+pub use crate::types::readlines::Readlines;
+
+pub use actix_http::body::{AnyBody, Body, BodySize, MessageBody, ResponseBody, SizedStream};
+
+#[cfg(feature = "__compress")]
+pub use actix_http::encoding::Decoder as Decompress;
+pub use actix_http::ResponseBuilder as BaseHttpResponseBuilder;
+pub use actix_http::{Extensions, Payload, PayloadStream, RequestHead, ResponseHead};
+pub use actix_router::{Path, ResourceDef, ResourcePath, Url};
+pub use actix_server::Server;
+pub use actix_service::{
+    always_ready, fn_factory, fn_service, forward_ready, Service, Transform,
+};
+
+pub(crate) fn insert_slash(mut patterns: Vec<String>) -> Vec<String> {
+    for path in &mut patterns {
+        if !path.is_empty() && !path.starts_with('/') {
+            path.insert(0, '/');
+        };
+    }
+    patterns
+}
+
+use crate::http::header::ContentEncoding;
+use actix_http::{Response, ResponseBuilder};
+
+struct Enc(ContentEncoding);
+
+/// Helper trait that allows to set specific encoding for response.
+pub trait BodyEncoding {
+    /// Get content encoding
+    fn get_encoding(&self) -> Option<ContentEncoding>;
+
+    /// Set content encoding
+    ///
+    /// Must be used with [`crate::middleware::Compress`] to take effect.
+    fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self;
+}
+
+impl BodyEncoding for ResponseBuilder {
+    fn get_encoding(&self) -> Option<ContentEncoding> {
+        self.extensions().get::<Enc>().map(|enc| enc.0)
+    }
+
+    fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
+        self.extensions_mut().insert(Enc(encoding));
+        self
+    }
+}
+
+impl<B> BodyEncoding for Response<B> {
+    fn get_encoding(&self) -> Option<ContentEncoding> {
+        self.extensions().get::<Enc>().map(|enc| enc.0)
+    }
+
+    fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
+        self.extensions_mut().insert(Enc(encoding));
+        self
+    }
+}
+
+impl BodyEncoding for crate::HttpResponseBuilder {
+    fn get_encoding(&self) -> Option<ContentEncoding> {
+        self.extensions().get::<Enc>().map(|enc| enc.0)
+    }
+
+    fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
+        self.extensions_mut().insert(Enc(encoding));
+        self
+    }
+}
+
+impl<B> BodyEncoding for crate::HttpResponse<B> {
+    fn get_encoding(&self) -> Option<ContentEncoding> {
+        self.extensions().get::<Enc>().map(|enc| enc.0)
+    }
+
+    fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
+        self.extensions_mut().insert(Enc(encoding));
+        self
+    }
+}
diff --git a/src/error/error.rs b/src/error/error.rs
new file mode 100644
index 000000000..add290867
--- /dev/null
+++ b/src/error/error.rs
@@ -0,0 +1,76 @@
+use std::{error::Error as StdError, fmt};
+
+use actix_http::{body::AnyBody, Response};
+
+use crate::{HttpResponse, ResponseError};
+
+/// General purpose actix web error.
+///
+/// An actix web error is used to carry errors from `std::error`
+/// through actix in a convenient way.  It can be created through
+/// converting errors with `into()`.
+///
+/// Whenever it is created from an external object a response error is created
+/// for it that can be used to create an HTTP response from it this means that
+/// if you have access to an actix `Error` you can always get a
+/// `ResponseError` reference from it.
+pub struct Error {
+    cause: Box<dyn ResponseError>,
+}
+
+impl Error {
+    /// Returns the reference to the underlying `ResponseError`.
+    pub fn as_response_error(&self) -> &dyn ResponseError {
+        self.cause.as_ref()
+    }
+
+    /// Similar to `as_response_error` but downcasts.
+    pub fn as_error<T: ResponseError + 'static>(&self) -> Option<&T> {
+        <dyn ResponseError>::downcast_ref(self.cause.as_ref())
+    }
+
+    /// Shortcut for creating an `HttpResponse`.
+    pub fn error_response(&self) -> HttpResponse {
+        self.cause.error_response()
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(&self.cause, f)
+    }
+}
+
+impl fmt::Debug for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:?}", &self.cause)
+    }
+}
+
+impl StdError for Error {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        // TODO: populate if replacement for Box<dyn Error> is found
+        None
+    }
+}
+
+impl From<std::convert::Infallible> for Error {
+    fn from(val: std::convert::Infallible) -> Self {
+        match val {}
+    }
+}
+
+/// `Error` for any error that implements `ResponseError`
+impl<T: ResponseError + 'static> From<T> for Error {
+    fn from(err: T) -> Error {
+        Error {
+            cause: Box::new(err),
+        }
+    }
+}
+
+impl From<Error> for Response<AnyBody> {
+    fn from(err: Error) -> Response<AnyBody> {
+        err.error_response().into()
+    }
+}
diff --git a/src/error/internal.rs b/src/error/internal.rs
index 23b7dc31e..1d9ca904e 100644
--- a/src/error/internal.rs
+++ b/src/error/internal.rs
@@ -1,9 +1,9 @@
 use std::{cell::RefCell, fmt, io::Write as _};
 
-use actix_http::{body::Body, header, Response, StatusCode};
+use actix_http::{body::Body, header, StatusCode};
 use bytes::{BufMut as _, BytesMut};
 
-use crate::{Error, HttpResponse, ResponseError};
+use crate::{Error, HttpRequest, HttpResponse, Responder, ResponseError};
 
 /// Wraps errors to alter the generated response status code.
 ///
@@ -77,10 +77,10 @@ where
         }
     }
 
-    fn error_response(&self) -> Response<Body> {
+    fn error_response(&self) -> HttpResponse {
         match self.status {
             InternalErrorType::Status(status) => {
-                let mut res = Response::new(status);
+                let mut res = HttpResponse::new(status);
                 let mut buf = BytesMut::new().writer();
                 let _ = write!(buf, "{}", self);
 
@@ -88,20 +88,29 @@ where
                     header::CONTENT_TYPE,
                     header::HeaderValue::from_static("text/plain; charset=utf-8"),
                 );
-                res.set_body(Body::from(buf.into_inner())).into()
+                res.set_body(Body::from(buf.into_inner()))
             }
 
             InternalErrorType::Response(ref resp) => {
                 if let Some(resp) = resp.borrow_mut().take() {
-                    resp.into()
+                    resp
                 } else {
-                    Response::new(StatusCode::INTERNAL_SERVER_ERROR)
+                    HttpResponse::new(StatusCode::INTERNAL_SERVER_ERROR)
                 }
             }
         }
     }
 }
 
+impl<T> Responder for InternalError<T>
+where
+    T: fmt::Debug + fmt::Display + 'static,
+{
+    fn respond_to(self, _: &HttpRequest) -> HttpResponse {
+        HttpResponse::from_error(self)
+    }
+}
+
 macro_rules! error_helper {
     ($name:ident, $status:ident) => {
         paste::paste! {
@@ -171,134 +180,134 @@ error_helper!(
 
 #[cfg(test)]
 mod tests {
-    use actix_http::{error::ParseError, Response};
+    use actix_http::error::ParseError;
 
     use super::*;
 
     #[test]
     fn test_internal_error() {
         let err = InternalError::from_response(ParseError::Method, HttpResponse::Ok().finish());
-        let resp: Response<Body> = err.error_response();
+        let resp: HttpResponse = err.error_response();
         assert_eq!(resp.status(), StatusCode::OK);
     }
 
     #[test]
     fn test_error_helpers() {
-        let res: Response<Body> = ErrorBadRequest("err").into();
+        let res: HttpResponse = ErrorBadRequest("err").into();
         assert_eq!(res.status(), StatusCode::BAD_REQUEST);
 
-        let res: Response<Body> = ErrorUnauthorized("err").into();
+        let res: HttpResponse = ErrorUnauthorized("err").into();
         assert_eq!(res.status(), StatusCode::UNAUTHORIZED);
 
-        let res: Response<Body> = ErrorPaymentRequired("err").into();
+        let res: HttpResponse = ErrorPaymentRequired("err").into();
         assert_eq!(res.status(), StatusCode::PAYMENT_REQUIRED);
 
-        let res: Response<Body> = ErrorForbidden("err").into();
+        let res: HttpResponse = ErrorForbidden("err").into();
         assert_eq!(res.status(), StatusCode::FORBIDDEN);
 
-        let res: Response<Body> = ErrorNotFound("err").into();
+        let res: HttpResponse = ErrorNotFound("err").into();
         assert_eq!(res.status(), StatusCode::NOT_FOUND);
 
-        let res: Response<Body> = ErrorMethodNotAllowed("err").into();
+        let res: HttpResponse = ErrorMethodNotAllowed("err").into();
         assert_eq!(res.status(), StatusCode::METHOD_NOT_ALLOWED);
 
-        let res: Response<Body> = ErrorNotAcceptable("err").into();
+        let res: HttpResponse = ErrorNotAcceptable("err").into();
         assert_eq!(res.status(), StatusCode::NOT_ACCEPTABLE);
 
-        let res: Response<Body> = ErrorProxyAuthenticationRequired("err").into();
+        let res: HttpResponse = ErrorProxyAuthenticationRequired("err").into();
         assert_eq!(res.status(), StatusCode::PROXY_AUTHENTICATION_REQUIRED);
 
-        let res: Response<Body> = ErrorRequestTimeout("err").into();
+        let res: HttpResponse = ErrorRequestTimeout("err").into();
         assert_eq!(res.status(), StatusCode::REQUEST_TIMEOUT);
 
-        let res: Response<Body> = ErrorConflict("err").into();
+        let res: HttpResponse = ErrorConflict("err").into();
         assert_eq!(res.status(), StatusCode::CONFLICT);
 
-        let res: Response<Body> = ErrorGone("err").into();
+        let res: HttpResponse = ErrorGone("err").into();
         assert_eq!(res.status(), StatusCode::GONE);
 
-        let res: Response<Body> = ErrorLengthRequired("err").into();
+        let res: HttpResponse = ErrorLengthRequired("err").into();
         assert_eq!(res.status(), StatusCode::LENGTH_REQUIRED);
 
-        let res: Response<Body> = ErrorPreconditionFailed("err").into();
+        let res: HttpResponse = ErrorPreconditionFailed("err").into();
         assert_eq!(res.status(), StatusCode::PRECONDITION_FAILED);
 
-        let res: Response<Body> = ErrorPayloadTooLarge("err").into();
+        let res: HttpResponse = ErrorPayloadTooLarge("err").into();
         assert_eq!(res.status(), StatusCode::PAYLOAD_TOO_LARGE);
 
-        let res: Response<Body> = ErrorUriTooLong("err").into();
+        let res: HttpResponse = ErrorUriTooLong("err").into();
         assert_eq!(res.status(), StatusCode::URI_TOO_LONG);
 
-        let res: Response<Body> = ErrorUnsupportedMediaType("err").into();
+        let res: HttpResponse = ErrorUnsupportedMediaType("err").into();
         assert_eq!(res.status(), StatusCode::UNSUPPORTED_MEDIA_TYPE);
 
-        let res: Response<Body> = ErrorRangeNotSatisfiable("err").into();
+        let res: HttpResponse = ErrorRangeNotSatisfiable("err").into();
         assert_eq!(res.status(), StatusCode::RANGE_NOT_SATISFIABLE);
 
-        let res: Response<Body> = ErrorExpectationFailed("err").into();
+        let res: HttpResponse = ErrorExpectationFailed("err").into();
         assert_eq!(res.status(), StatusCode::EXPECTATION_FAILED);
 
-        let res: Response<Body> = ErrorImATeapot("err").into();
+        let res: HttpResponse = ErrorImATeapot("err").into();
         assert_eq!(res.status(), StatusCode::IM_A_TEAPOT);
 
-        let res: Response<Body> = ErrorMisdirectedRequest("err").into();
+        let res: HttpResponse = ErrorMisdirectedRequest("err").into();
         assert_eq!(res.status(), StatusCode::MISDIRECTED_REQUEST);
 
-        let res: Response<Body> = ErrorUnprocessableEntity("err").into();
+        let res: HttpResponse = ErrorUnprocessableEntity("err").into();
         assert_eq!(res.status(), StatusCode::UNPROCESSABLE_ENTITY);
 
-        let res: Response<Body> = ErrorLocked("err").into();
+        let res: HttpResponse = ErrorLocked("err").into();
         assert_eq!(res.status(), StatusCode::LOCKED);
 
-        let res: Response<Body> = ErrorFailedDependency("err").into();
+        let res: HttpResponse = ErrorFailedDependency("err").into();
         assert_eq!(res.status(), StatusCode::FAILED_DEPENDENCY);
 
-        let res: Response<Body> = ErrorUpgradeRequired("err").into();
+        let res: HttpResponse = ErrorUpgradeRequired("err").into();
         assert_eq!(res.status(), StatusCode::UPGRADE_REQUIRED);
 
-        let res: Response<Body> = ErrorPreconditionRequired("err").into();
+        let res: HttpResponse = ErrorPreconditionRequired("err").into();
         assert_eq!(res.status(), StatusCode::PRECONDITION_REQUIRED);
 
-        let res: Response<Body> = ErrorTooManyRequests("err").into();
+        let res: HttpResponse = ErrorTooManyRequests("err").into();
         assert_eq!(res.status(), StatusCode::TOO_MANY_REQUESTS);
 
-        let res: Response<Body> = ErrorRequestHeaderFieldsTooLarge("err").into();
+        let res: HttpResponse = ErrorRequestHeaderFieldsTooLarge("err").into();
         assert_eq!(res.status(), StatusCode::REQUEST_HEADER_FIELDS_TOO_LARGE);
 
-        let res: Response<Body> = ErrorUnavailableForLegalReasons("err").into();
+        let res: HttpResponse = ErrorUnavailableForLegalReasons("err").into();
         assert_eq!(res.status(), StatusCode::UNAVAILABLE_FOR_LEGAL_REASONS);
 
-        let res: Response<Body> = ErrorInternalServerError("err").into();
+        let res: HttpResponse = ErrorInternalServerError("err").into();
         assert_eq!(res.status(), StatusCode::INTERNAL_SERVER_ERROR);
 
-        let res: Response<Body> = ErrorNotImplemented("err").into();
+        let res: HttpResponse = ErrorNotImplemented("err").into();
         assert_eq!(res.status(), StatusCode::NOT_IMPLEMENTED);
 
-        let res: Response<Body> = ErrorBadGateway("err").into();
+        let res: HttpResponse = ErrorBadGateway("err").into();
         assert_eq!(res.status(), StatusCode::BAD_GATEWAY);
 
-        let res: Response<Body> = ErrorServiceUnavailable("err").into();
+        let res: HttpResponse = ErrorServiceUnavailable("err").into();
         assert_eq!(res.status(), StatusCode::SERVICE_UNAVAILABLE);
 
-        let res: Response<Body> = ErrorGatewayTimeout("err").into();
+        let res: HttpResponse = ErrorGatewayTimeout("err").into();
         assert_eq!(res.status(), StatusCode::GATEWAY_TIMEOUT);
 
-        let res: Response<Body> = ErrorHttpVersionNotSupported("err").into();
+        let res: HttpResponse = ErrorHttpVersionNotSupported("err").into();
         assert_eq!(res.status(), StatusCode::HTTP_VERSION_NOT_SUPPORTED);
 
-        let res: Response<Body> = ErrorVariantAlsoNegotiates("err").into();
+        let res: HttpResponse = ErrorVariantAlsoNegotiates("err").into();
         assert_eq!(res.status(), StatusCode::VARIANT_ALSO_NEGOTIATES);
 
-        let res: Response<Body> = ErrorInsufficientStorage("err").into();
+        let res: HttpResponse = ErrorInsufficientStorage("err").into();
         assert_eq!(res.status(), StatusCode::INSUFFICIENT_STORAGE);
 
-        let res: Response<Body> = ErrorLoopDetected("err").into();
+        let res: HttpResponse = ErrorLoopDetected("err").into();
         assert_eq!(res.status(), StatusCode::LOOP_DETECTED);
 
-        let res: Response<Body> = ErrorNotExtended("err").into();
+        let res: HttpResponse = ErrorNotExtended("err").into();
         assert_eq!(res.status(), StatusCode::NOT_EXTENDED);
 
-        let res: Response<Body> = ErrorNetworkAuthenticationRequired("err").into();
+        let res: HttpResponse = ErrorNetworkAuthenticationRequired("err").into();
         assert_eq!(res.status(), StatusCode::NETWORK_AUTHENTICATION_REQUIRED);
     }
 }
diff --git a/actix-http/src/macros.rs b/src/error/macros.rs
similarity index 89%
rename from actix-http/src/macros.rs
rename to src/error/macros.rs
index be8e63d6e..38650c5e8 100644
--- a/actix-http/src/macros.rs
+++ b/src/error/macros.rs
@@ -1,5 +1,3 @@
-#[macro_export]
-#[doc(hidden)]
 macro_rules! downcast_get_type_id {
     () => {
         /// A helper method to get the type ID of the type
@@ -20,10 +18,8 @@ macro_rules! downcast_get_type_id {
         /// safe code cannot obtain a `PrivateHelper` instance by
         /// delegating to an existing implementation of `__private_get_type_id__`
         #[doc(hidden)]
-        fn __private_get_type_id__(
-            &self,
-            _: PrivateHelper,
-        ) -> (std::any::TypeId, PrivateHelper)
+        #[allow(dead_code)]
+        fn __private_get_type_id__(&self, _: PrivateHelper) -> (std::any::TypeId, PrivateHelper)
         where
             Self: 'static,
         {
@@ -32,19 +28,19 @@ macro_rules! downcast_get_type_id {
     };
 }
 
-//Generate implementation for dyn $name
-#[doc(hidden)]
-#[macro_export]
-macro_rules! downcast {
+// Generate implementation for dyn $name
+macro_rules! downcast_dyn {
     ($name:ident) => {
         /// A struct with a private constructor, for use with
         /// `__private_get_type_id__`. Its single field is private,
         /// ensuring that it can only be constructed from this module
         #[doc(hidden)]
+        #[allow(dead_code)]
         pub struct PrivateHelper(());
 
         impl dyn $name + 'static {
             /// Downcasts generic body to a specific type.
+            #[allow(dead_code)]
             pub fn downcast_ref<T: $name + 'static>(&self) -> Option<&T> {
                 if self.__private_get_type_id__(PrivateHelper(())).0
                     == std::any::TypeId::of::<T>()
@@ -61,6 +57,7 @@ macro_rules! downcast {
             }
 
             /// Downcasts a generic body to a mutable specific type.
+            #[allow(dead_code)]
             pub fn downcast_mut<T: $name + 'static>(&mut self) -> Option<&mut T> {
                 if self.__private_get_type_id__(PrivateHelper(())).0
                     == std::any::TypeId::of::<T>()
@@ -70,9 +67,7 @@ macro_rules! downcast {
                     // it requires returning a private type. We can therefore
                     // rely on the returned `TypeId`, which ensures that this
                     // case is correct.
-                    unsafe {
-                        Some(&mut *(self as *const dyn $name as *const T as *mut T))
-                    }
+                    unsafe { Some(&mut *(self as *const dyn $name as *const T as *mut T)) }
                 } else {
                     None
                 }
@@ -81,6 +76,8 @@ macro_rules! downcast {
     };
 }
 
+pub(crate) use {downcast_dyn, downcast_get_type_id};
+
 #[cfg(test)]
 mod tests {
     #![allow(clippy::upper_case_acronyms)]
@@ -89,7 +86,7 @@ mod tests {
         downcast_get_type_id!();
     }
 
-    downcast!(MB);
+    downcast_dyn!(MB);
 
     impl MB for String {}
     impl MB for () {}
diff --git a/src/error/mod.rs b/src/error/mod.rs
index 7be9f501b..3ccd5bba6 100644
--- a/src/error/mod.rs
+++ b/src/error/mod.rs
@@ -9,14 +9,21 @@ use url::ParseError as UrlParseError;
 
 use crate::http::StatusCode;
 
+#[allow(clippy::module_inception)]
+mod error;
 mod internal;
+mod macros;
+mod response_error;
 
+pub use self::error::Error;
 pub use self::internal::*;
+pub use self::response_error::ResponseError;
+pub(crate) use macros::{downcast_dyn, downcast_get_type_id};
 
 /// A convenience [`Result`](std::result::Result) for Actix Web operations.
 ///
 /// This type alias is generally used to avoid writing out `actix_http::Error` directly.
-pub type Result<T, E = actix_http::Error> = std::result::Result<T, E>;
+pub type Result<T, E = Error> = std::result::Result<T, E>;
 
 /// Errors which can occur when attempting to generate resource uri.
 #[derive(Debug, PartialEq, Display, Error, From)]
@@ -93,9 +100,17 @@ impl ResponseError for UrlencodedError {
 #[derive(Debug, Display, Error)]
 #[non_exhaustive]
 pub enum JsonPayloadError {
-    /// Payload size is bigger than allowed. (default: 32kB)
-    #[display(fmt = "Json payload size is bigger than allowed")]
-    Overflow,
+    /// Payload size is bigger than allowed & content length header set. (default: 2MB)
+    #[display(
+        fmt = "JSON payload ({} bytes) is larger than allowed (limit: {} bytes).",
+        length,
+        limit
+    )]
+    OverflowKnownLength { length: usize, limit: usize },
+
+    /// Payload size is bigger than allowed but no content length header set. (default: 2MB)
+    #[display(fmt = "JSON payload has exceeded limit ({} bytes).", limit)]
+    Overflow { limit: usize },
 
     /// Content type error
     #[display(fmt = "Content type error")]
@@ -123,7 +138,11 @@ impl From<PayloadError> for JsonPayloadError {
 impl ResponseError for JsonPayloadError {
     fn status_code(&self) -> StatusCode {
         match self {
-            Self::Overflow => StatusCode::PAYLOAD_TOO_LARGE,
+            Self::OverflowKnownLength {
+                length: _,
+                limit: _,
+            } => StatusCode::PAYLOAD_TOO_LARGE,
+            Self::Overflow { limit: _ } => StatusCode::PAYLOAD_TOO_LARGE,
             Self::Serialize(_) => StatusCode::INTERNAL_SERVER_ERROR,
             Self::Payload(err) => err.status_code(),
             _ => StatusCode::BAD_REQUEST,
@@ -208,7 +227,13 @@ mod tests {
 
     #[test]
     fn test_json_payload_error() {
-        let resp = JsonPayloadError::Overflow.error_response();
+        let resp = JsonPayloadError::OverflowKnownLength {
+            length: 0,
+            limit: 0,
+        }
+        .error_response();
+        assert_eq!(resp.status(), StatusCode::PAYLOAD_TOO_LARGE);
+        let resp = JsonPayloadError::Overflow { limit: 0 }.error_response();
         assert_eq!(resp.status(), StatusCode::PAYLOAD_TOO_LARGE);
         let resp = JsonPayloadError::ContentType.error_response();
         assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
diff --git a/src/error/response_error.rs b/src/error/response_error.rs
new file mode 100644
index 000000000..c3c543419
--- /dev/null
+++ b/src/error/response_error.rs
@@ -0,0 +1,148 @@
+//! `ResponseError` trait and foreign impls.
+
+use std::{
+    error::Error as StdError,
+    fmt,
+    io::{self, Write as _},
+};
+
+use actix_http::{body::AnyBody, header, Response, StatusCode};
+use bytes::BytesMut;
+
+use crate::error::{downcast_dyn, downcast_get_type_id};
+use crate::{helpers, HttpResponse};
+
+/// Errors that can generate responses.
+// TODO: add std::error::Error bound when replacement for Box<dyn Error> is found
+pub trait ResponseError: fmt::Debug + fmt::Display {
+    /// Returns appropriate status code for error.
+    ///
+    /// A 500 Internal Server Error is used by default. If [error_response](Self::error_response) is
+    /// also implemented and does not call `self.status_code()`, then this will not be used.
+    fn status_code(&self) -> StatusCode {
+        StatusCode::INTERNAL_SERVER_ERROR
+    }
+
+    /// Creates full response for error.
+    ///
+    /// By default, the generated response uses a 500 Internal Server Error status code, a
+    /// `Content-Type` of `text/plain`, and the body is set to `Self`'s `Display` impl.
+    fn error_response(&self) -> HttpResponse {
+        let mut res = HttpResponse::new(self.status_code());
+
+        let mut buf = BytesMut::new();
+        let _ = write!(helpers::MutWriter(&mut buf), "{}", self);
+
+        res.headers_mut().insert(
+            header::CONTENT_TYPE,
+            header::HeaderValue::from_static("text/plain; charset=utf-8"),
+        );
+
+        res.set_body(AnyBody::from(buf))
+    }
+
+    downcast_get_type_id!();
+}
+
+downcast_dyn!(ResponseError);
+
+impl ResponseError for Box<dyn StdError + 'static> {}
+
+#[cfg(feature = "openssl")]
+impl ResponseError for actix_tls::accept::openssl::SslError {}
+
+impl ResponseError for serde::de::value::Error {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::BAD_REQUEST
+    }
+}
+
+impl ResponseError for serde_json::Error {}
+
+impl ResponseError for serde_urlencoded::ser::Error {}
+
+impl ResponseError for std::str::Utf8Error {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::BAD_REQUEST
+    }
+}
+
+impl ResponseError for std::io::Error {
+    fn status_code(&self) -> StatusCode {
+        // TODO: decide if these errors should consider not found or permission errors
+        match self.kind() {
+            io::ErrorKind::NotFound => StatusCode::NOT_FOUND,
+            io::ErrorKind::PermissionDenied => StatusCode::FORBIDDEN,
+            _ => StatusCode::INTERNAL_SERVER_ERROR,
+        }
+    }
+}
+
+impl ResponseError for actix_http::error::HttpError {}
+
+impl ResponseError for actix_http::Error {
+    fn status_code(&self) -> StatusCode {
+        // TODO: map error kinds to status code better
+        StatusCode::INTERNAL_SERVER_ERROR
+    }
+
+    fn error_response(&self) -> HttpResponse {
+        HttpResponse::new(self.status_code()).set_body(self.to_string().into())
+    }
+}
+
+impl ResponseError for actix_http::header::InvalidHeaderValue {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::BAD_REQUEST
+    }
+}
+
+impl ResponseError for actix_http::error::ParseError {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::BAD_REQUEST
+    }
+}
+
+impl ResponseError for actix_http::error::BlockingError {}
+
+impl ResponseError for actix_http::error::PayloadError {
+    fn status_code(&self) -> StatusCode {
+        match *self {
+            actix_http::error::PayloadError::Overflow => StatusCode::PAYLOAD_TOO_LARGE,
+            _ => StatusCode::BAD_REQUEST,
+        }
+    }
+}
+
+impl ResponseError for actix_http::ws::ProtocolError {}
+
+impl ResponseError for actix_http::error::ContentTypeError {
+    fn status_code(&self) -> StatusCode {
+        StatusCode::BAD_REQUEST
+    }
+}
+
+impl ResponseError for actix_http::ws::HandshakeError {
+    fn error_response(&self) -> HttpResponse {
+        Response::from(self).into()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_error_casting() {
+        use actix_http::error::{ContentTypeError, PayloadError};
+
+        let err = PayloadError::Overflow;
+        let resp_err: &dyn ResponseError = &err;
+
+        let err = resp_err.downcast_ref::<PayloadError>().unwrap();
+        assert_eq!(err.to_string(), "Payload reached size limit.");
+
+        let not_err = resp_err.downcast_ref::<ContentTypeError>();
+        assert!(not_err.is_none());
+    }
+}
diff --git a/src/extract.rs b/src/extract.rs
index 82746708c..8cd603338 100644
--- a/src/extract.rs
+++ b/src/extract.rs
@@ -1,12 +1,14 @@
 //! Request extractors
 
 use std::{
+    convert::Infallible,
     future::Future,
     pin::Pin,
     task::{Context, Poll},
 };
 
-use actix_utils::future::{ready, Ready};
+use actix_http::http::{Method, Uri};
+use actix_utils::future::{ok, Ready};
 use futures_core::ready;
 
 use crate::{dev::Payload, Error, HttpRequest};
@@ -68,13 +70,12 @@ pub trait FromRequest: Sized {
 ///
 /// If the FromRequest for T fails, return None rather than returning an error response
 ///
-/// ## Example
-///
+/// # Examples
 /// ```
 /// use actix_web::{web, dev, App, Error, HttpRequest, FromRequest};
 /// use actix_web::error::ErrorBadRequest;
 /// use futures_util::future::{ok, err, Ready};
-/// use serde_derive::Deserialize;
+/// use serde::Deserialize;
 /// use rand;
 ///
 /// #[derive(Debug, Deserialize)]
@@ -158,13 +159,12 @@ where
 ///
 /// If the `FromRequest` for T fails, inject Err into handler rather than returning an error response
 ///
-/// ## Example
-///
+/// # Examples
 /// ```
 /// use actix_web::{web, dev, App, Result, Error, HttpRequest, FromRequest};
 /// use actix_web::error::ErrorBadRequest;
 /// use futures_util::future::{ok, err, Ready};
-/// use serde_derive::Deserialize;
+/// use serde::Deserialize;
 /// use rand;
 ///
 /// #[derive(Debug, Deserialize)]
@@ -235,13 +235,57 @@ where
     }
 }
 
+/// Extract the request's URI.
+///
+/// # Examples
+/// ```
+/// use actix_web::{http::Uri, web, App, Responder};
+///
+/// async fn handler(uri: Uri) -> impl Responder {
+///     format!("Requested path: {}", uri.path())
+/// }
+///
+/// let app = App::new().default_service(web::to(handler));
+/// ```
+impl FromRequest for Uri {
+    type Error = Infallible;
+    type Future = Ready<Result<Self, Self::Error>>;
+    type Config = ();
+
+    fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future {
+        ok(req.uri().clone())
+    }
+}
+
+/// Extract the request's method.
+///
+/// # Examples
+/// ```
+/// use actix_web::{http::Method, web, App, Responder};
+///
+/// async fn handler(method: Method) -> impl Responder {
+///     format!("Request method: {}", method)
+/// }
+///
+/// let app = App::new().default_service(web::to(handler));
+/// ```
+impl FromRequest for Method {
+    type Error = Infallible;
+    type Future = Ready<Result<Self, Self::Error>>;
+    type Config = ();
+
+    fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future {
+        ok(req.method().clone())
+    }
+}
+
 #[doc(hidden)]
 impl FromRequest for () {
-    type Error = Error;
-    type Future = Ready<Result<(), Error>>;
+    type Error = Infallible;
+    type Future = Ready<Result<Self, Self::Error>>;
 
     fn from_request(_: &HttpRequest, _: &mut Payload) -> Self::Future {
-        ready(Ok(()))
+        ok(())
     }
 }
 
@@ -347,7 +391,7 @@ mod m {
 mod tests {
     use actix_http::http::header;
     use bytes::Bytes;
-    use serde_derive::Deserialize;
+    use serde::Deserialize;
 
     use super::*;
     use crate::test::TestRequest;
@@ -428,4 +472,18 @@ mod tests {
             .unwrap();
         assert!(r.is_err());
     }
+
+    #[actix_rt::test]
+    async fn test_uri() {
+        let req = TestRequest::default().uri("/foo/bar").to_http_request();
+        let uri = Uri::extract(&req).await.unwrap();
+        assert_eq!(uri.path(), "/foo/bar");
+    }
+
+    #[actix_rt::test]
+    async fn test_method() {
+        let req = TestRequest::default().method(Method::GET).to_http_request();
+        let method = Method::extract(&req).await.unwrap();
+        assert_eq!(method, Method::GET);
+    }
 }
diff --git a/src/handler.rs b/src/handler.rs
index 822dcafdd..bc91ce41b 100644
--- a/src/handler.rs
+++ b/src/handler.rs
@@ -3,18 +3,14 @@ use std::marker::PhantomData;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
-use actix_http::Error;
 use actix_service::{Service, ServiceFactory};
 use actix_utils::future::{ready, Ready};
 use futures_core::ready;
 use pin_project::pin_project;
 
 use crate::{
-    extract::FromRequest,
-    request::HttpRequest,
-    responder::Responder,
-    response::HttpResponse,
     service::{ServiceRequest, ServiceResponse},
+    Error, FromRequest, HttpRequest, HttpResponse, Responder,
 };
 
 /// A request handler is an async function that accepts zero or more parameters that can be
diff --git a/src/helpers.rs b/src/helpers.rs
new file mode 100644
index 000000000..1d2679fce
--- /dev/null
+++ b/src/helpers.rs
@@ -0,0 +1,25 @@
+use std::io;
+
+use bytes::BufMut;
+
+/// An `io::Write`r that only requires mutable reference and assumes that there is space available
+/// in the buffer for every write operation or that it can be extended implicitly (like
+/// `bytes::BytesMut`, for example).
+///
+/// This is slightly faster (~10%) than `bytes::buf::Writer` in such cases because it does not
+/// perform a remaining length check before writing.
+pub(crate) struct MutWriter<'a, B>(pub(crate) &'a mut B);
+
+impl<'a, B> io::Write for MutWriter<'a, B>
+where
+    B: BufMut,
+{
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.0.put_slice(buf);
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
diff --git a/src/http/header/accept.rs b/src/http/header/accept.rs
index 1b6a963da..75366dfae 100644
--- a/src/http/header/accept.rs
+++ b/src/http/header/accept.rs
@@ -5,7 +5,7 @@ use mime::Mime;
 use super::{qitem, QualityItem};
 use crate::http::header;
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Accept` header, defined in [RFC7231](http://tools.ietf.org/html/rfc7231#section-5.3.2)
     ///
     /// The `Accept` header field can be used by user agents to specify
@@ -81,14 +81,14 @@ crate::__define_common_header! {
 
     test_accept {
         // Tests from the RFC
-         crate::__common_header_test!(
+         crate::http::header::common_header_test!(
             test1,
             vec![b"audio/*; q=0.2, audio/basic"],
             Some(Accept(vec![
                 QualityItem::new("audio/*".parse().unwrap(), q(200)),
                 qitem("audio/basic".parse().unwrap()),
                 ])));
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test2,
             vec![b"text/plain; q=0.5, text/html, text/x-dvi; q=0.8, text/x-c"],
             Some(Accept(vec![
@@ -100,13 +100,13 @@ crate::__define_common_header! {
                 qitem("text/x-c".parse().unwrap()),
                 ])));
         // Custom tests
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test3,
             vec![b"text/plain; charset=utf-8"],
             Some(Accept(vec![
                 qitem(mime::TEXT_PLAIN_UTF_8),
                 ])));
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test4,
             vec![b"text/plain; charset=utf-8; q=0.5"],
             Some(Accept(vec![
diff --git a/src/http/header/accept_charset.rs b/src/http/header/accept_charset.rs
index 2c6a0b9f6..bb7d86516 100644
--- a/src/http/header/accept_charset.rs
+++ b/src/http/header/accept_charset.rs
@@ -1,6 +1,6 @@
 use super::{Charset, QualityItem, ACCEPT_CHARSET};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Accept-Charset` header, defined in
     /// [RFC7231](http://tools.ietf.org/html/rfc7231#section-5.3.3)
     ///
@@ -57,6 +57,6 @@ crate::__define_common_header! {
 
     test_accept_charset {
         // Test case from RFC
-        crate::__common_header_test!(test1, vec![b"iso-8859-5, unicode-1-1;q=0.8"]);
+        crate::http::header::common_header_test!(test1, vec![b"iso-8859-5, unicode-1-1;q=0.8"]);
     }
 }
diff --git a/src/http/header/accept_encoding.rs b/src/http/header/accept_encoding.rs
index 734a435b3..cfd29bf77 100644
--- a/src/http/header/accept_encoding.rs
+++ b/src/http/header/accept_encoding.rs
@@ -64,12 +64,12 @@ header! {
 
     test_accept_encoding {
         // From the RFC
-        crate::__common_header_test!(test1, vec![b"compress, gzip"]);
-        crate::__common_header_test!(test2, vec![b""], Some(AcceptEncoding(vec![])));
-        crate::__common_header_test!(test3, vec![b"*"]);
+        crate::http::header::common_header_test!(test1, vec![b"compress, gzip"]);
+        crate::http::header::common_header_test!(test2, vec![b""], Some(AcceptEncoding(vec![])));
+        crate::http::header::common_header_test!(test3, vec![b"*"]);
         // Note: Removed quality 1 from gzip
-        crate::__common_header_test!(test4, vec![b"compress;q=0.5, gzip"]);
+        crate::http::header::common_header_test!(test4, vec![b"compress;q=0.5, gzip"]);
         // Note: Removed quality 1 from gzip
-        crate::__common_header_test!(test5, vec![b"gzip, identity; q=0.5, *;q=0"]);
+        crate::http::header::common_header_test!(test5, vec![b"gzip, identity; q=0.5, *;q=0"]);
     }
 }
diff --git a/src/http/header/accept_language.rs b/src/http/header/accept_language.rs
index 034946d4d..1552f6578 100644
--- a/src/http/header/accept_language.rs
+++ b/src/http/header/accept_language.rs
@@ -2,7 +2,7 @@ use language_tags::LanguageTag;
 
 use super::{QualityItem, ACCEPT_LANGUAGE};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Accept-Language` header, defined in
     /// [RFC7231](http://tools.ietf.org/html/rfc7231#section-5.3.5)
     ///
@@ -53,9 +53,9 @@ crate::__define_common_header! {
 
     test_accept_language {
         // From the RFC
-        crate::__common_header_test!(test1, vec![b"da, en-gb;q=0.8, en;q=0.7"]);
+        crate::http::header::common_header_test!(test1, vec![b"da, en-gb;q=0.8, en;q=0.7"]);
         // Own test
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test2, vec![b"en-US, en; q=0.5, fr"],
             Some(AcceptLanguage(vec![
                 qitem("en-US".parse().unwrap()),
diff --git a/src/http/header/allow.rs b/src/http/header/allow.rs
index 15a627b8f..946f70e0a 100644
--- a/src/http/header/allow.rs
+++ b/src/http/header/allow.rs
@@ -1,7 +1,7 @@
 use crate::http::header;
 use actix_http::http::Method;
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Allow` header, defined in [RFC7231](http://tools.ietf.org/html/rfc7231#section-7.4.1)
     ///
     /// The `Allow` header field lists the set of methods advertised as
@@ -49,12 +49,12 @@ crate::__define_common_header! {
 
     test_allow {
         // From the RFC
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test1,
             vec![b"GET, HEAD, PUT"],
             Some(HeaderField(vec![Method::GET, Method::HEAD, Method::PUT])));
         // Own tests
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test2,
             vec![b"OPTIONS, GET, PUT, POST, DELETE, HEAD, TRACE, CONNECT, PATCH"],
             Some(HeaderField(vec![
@@ -67,7 +67,7 @@ crate::__define_common_header! {
                 Method::TRACE,
                 Method::CONNECT,
                 Method::PATCH])));
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test3,
             vec![b""],
             Some(HeaderField(Vec::<Method>::new())));
diff --git a/src/http/header/cache_control.rs b/src/http/header/cache_control.rs
index 620c576ae..05903e3a3 100644
--- a/src/http/header/cache_control.rs
+++ b/src/http/header/cache_control.rs
@@ -49,9 +49,9 @@ use crate::http::header;
 #[derive(PartialEq, Clone, Debug)]
 pub struct CacheControl(pub Vec<CacheDirective>);
 
-crate::__common_header_deref!(CacheControl => Vec<CacheDirective>);
+crate::http::header::common_header_deref!(CacheControl => Vec<CacheDirective>);
 
-// TODO: this could just be the __define_common_header! macro
+// TODO: this could just be the crate::http::header::common_header! macro
 impl Header for CacheControl {
     fn name() -> header::HeaderName {
         header::CACHE_CONTROL
diff --git a/src/http/header/content_disposition.rs b/src/http/header/content_disposition.rs
index 71c610157..9f67baffb 100644
--- a/src/http/header/content_disposition.rs
+++ b/src/http/header/content_disposition.rs
@@ -410,41 +410,33 @@ impl ContentDisposition {
 
     /// Return the value of *name* if exists.
     pub fn get_name(&self) -> Option<&str> {
-        self.parameters.iter().filter_map(|p| p.as_name()).next()
+        self.parameters.iter().find_map(DispositionParam::as_name)
     }
 
     /// Return the value of *filename* if exists.
     pub fn get_filename(&self) -> Option<&str> {
         self.parameters
             .iter()
-            .filter_map(|p| p.as_filename())
-            .next()
+            .find_map(DispositionParam::as_filename)
     }
 
     /// Return the value of *filename\** if exists.
     pub fn get_filename_ext(&self) -> Option<&ExtendedValue> {
         self.parameters
             .iter()
-            .filter_map(|p| p.as_filename_ext())
-            .next()
+            .find_map(DispositionParam::as_filename_ext)
     }
 
     /// Return the value of the parameter which the `name` matches.
     pub fn get_unknown(&self, name: impl AsRef<str>) -> Option<&str> {
         let name = name.as_ref();
-        self.parameters
-            .iter()
-            .filter_map(|p| p.as_unknown(name))
-            .next()
+        self.parameters.iter().find_map(|p| p.as_unknown(name))
     }
 
     /// Return the value of the extended parameter which the `name` matches.
     pub fn get_unknown_ext(&self, name: impl AsRef<str>) -> Option<&ExtendedValue> {
         let name = name.as_ref();
-        self.parameters
-            .iter()
-            .filter_map(|p| p.as_unknown_ext(name))
-            .next()
+        self.parameters.iter().find_map(|p| p.as_unknown_ext(name))
     }
 }
 
diff --git a/src/http/header/content_language.rs b/src/http/header/content_language.rs
index c2469edd1..604ada83c 100644
--- a/src/http/header/content_language.rs
+++ b/src/http/header/content_language.rs
@@ -1,7 +1,7 @@
 use super::{QualityItem, CONTENT_LANGUAGE};
 use language_tags::LanguageTag;
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Content-Language` header, defined in
     /// [RFC7231](https://tools.ietf.org/html/rfc7231#section-3.1.3.2)
     ///
@@ -50,7 +50,7 @@ crate::__define_common_header! {
     (ContentLanguage, CONTENT_LANGUAGE) => (QualityItem<LanguageTag>)+
 
     test_content_language {
-        crate::__common_header_test!(test1, vec![b"da"]);
-        crate::__common_header_test!(test2, vec![b"mi, en"]);
+        crate::http::header::common_header_test!(test1, vec![b"da"]);
+        crate::http::header::common_header_test!(test2, vec![b"mi, en"]);
     }
 }
diff --git a/src/http/header/content_range.rs b/src/http/header/content_range.rs
index ba0d51742..3bdead2c0 100644
--- a/src/http/header/content_range.rs
+++ b/src/http/header/content_range.rs
@@ -4,65 +4,65 @@ use std::str::FromStr;
 use super::{HeaderValue, IntoHeaderValue, InvalidHeaderValue, Writer, CONTENT_RANGE};
 use crate::error::ParseError;
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Content-Range` header, defined in
     /// [RFC7233](http://tools.ietf.org/html/rfc7233#section-4.2)
     (ContentRange, CONTENT_RANGE) => [ContentRangeSpec]
 
     test_content_range {
-        crate::__common_header_test!(test_bytes,
+        crate::http::header::common_header_test!(test_bytes,
             vec![b"bytes 0-499/500"],
             Some(ContentRange(ContentRangeSpec::Bytes {
                 range: Some((0, 499)),
                 instance_length: Some(500)
             })));
 
-        crate::__common_header_test!(test_bytes_unknown_len,
+        crate::http::header::common_header_test!(test_bytes_unknown_len,
             vec![b"bytes 0-499/*"],
             Some(ContentRange(ContentRangeSpec::Bytes {
                 range: Some((0, 499)),
                 instance_length: None
             })));
 
-        crate::__common_header_test!(test_bytes_unknown_range,
+        crate::http::header::common_header_test!(test_bytes_unknown_range,
             vec![b"bytes */500"],
             Some(ContentRange(ContentRangeSpec::Bytes {
                 range: None,
                 instance_length: Some(500)
             })));
 
-        crate::__common_header_test!(test_unregistered,
+        crate::http::header::common_header_test!(test_unregistered,
             vec![b"seconds 1-2"],
             Some(ContentRange(ContentRangeSpec::Unregistered {
                 unit: "seconds".to_owned(),
                 resp: "1-2".to_owned()
             })));
 
-        crate::__common_header_test!(test_no_len,
+        crate::http::header::common_header_test!(test_no_len,
             vec![b"bytes 0-499"],
             None::<ContentRange>);
 
-        crate::__common_header_test!(test_only_unit,
+        crate::http::header::common_header_test!(test_only_unit,
             vec![b"bytes"],
             None::<ContentRange>);
 
-        crate::__common_header_test!(test_end_less_than_start,
+        crate::http::header::common_header_test!(test_end_less_than_start,
             vec![b"bytes 499-0/500"],
             None::<ContentRange>);
 
-        crate::__common_header_test!(test_blank,
+        crate::http::header::common_header_test!(test_blank,
             vec![b""],
             None::<ContentRange>);
 
-        crate::__common_header_test!(test_bytes_many_spaces,
+        crate::http::header::common_header_test!(test_bytes_many_spaces,
             vec![b"bytes 1-2/500 3"],
             None::<ContentRange>);
 
-        crate::__common_header_test!(test_bytes_many_slashes,
+        crate::http::header::common_header_test!(test_bytes_many_slashes,
             vec![b"bytes 1-2/500/600"],
             None::<ContentRange>);
 
-        crate::__common_header_test!(test_bytes_many_dashes,
+        crate::http::header::common_header_test!(test_bytes_many_dashes,
             vec![b"bytes 1-2-3/500"],
             None::<ContentRange>);
 
diff --git a/src/http/header/content_type.rs b/src/http/header/content_type.rs
index 65cb2a986..e1c419c22 100644
--- a/src/http/header/content_type.rs
+++ b/src/http/header/content_type.rs
@@ -1,7 +1,7 @@
 use super::CONTENT_TYPE;
 use mime::Mime;
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Content-Type` header, defined in
     /// [RFC7231](http://tools.ietf.org/html/rfc7231#section-3.1.1.5)
     ///
@@ -52,7 +52,7 @@ crate::__define_common_header! {
     (ContentType, CONTENT_TYPE) => [Mime]
 
     test_content_type {
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test1,
             vec![b"text/html"],
             Some(HeaderField(mime::TEXT_HTML)));
diff --git a/src/http/header/date.rs b/src/http/header/date.rs
index 982a1455c..4d1717886 100644
--- a/src/http/header/date.rs
+++ b/src/http/header/date.rs
@@ -1,7 +1,7 @@
 use super::{HttpDate, DATE};
 use std::time::SystemTime;
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Date` header, defined in [RFC7231](http://tools.ietf.org/html/rfc7231#section-7.1.1.2)
     ///
     /// The `Date` header field represents the date and time at which the
@@ -32,7 +32,7 @@ crate::__define_common_header! {
     (Date, DATE) => [HttpDate]
 
     test_date {
-        crate::__common_header_test!(test1, vec![b"Tue, 15 Nov 1994 08:12:31 GMT"]);
+        crate::http::header::common_header_test!(test1, vec![b"Tue, 15 Nov 1994 08:12:31 GMT"]);
     }
 }
 
diff --git a/src/http/header/encoding.rs b/src/http/header/encoding.rs
index aa49dea45..ce31c100f 100644
--- a/src/http/header/encoding.rs
+++ b/src/http/header/encoding.rs
@@ -1,7 +1,7 @@
 use std::{fmt, str};
 
 pub use self::Encoding::{
-    Brotli, Chunked, Compress, Deflate, EncodingExt, Gzip, Identity, Trailers,
+    Brotli, Chunked, Compress, Deflate, EncodingExt, Gzip, Identity, Trailers, Zstd,
 };
 
 /// A value to represent an encoding used in `Transfer-Encoding`
@@ -22,6 +22,8 @@ pub enum Encoding {
     Identity,
     /// The `trailers` encoding.
     Trailers,
+    /// The `zstd` encoding.
+    Zstd,
     /// Some other encoding that is less common, can be any String.
     EncodingExt(String),
 }
@@ -36,6 +38,7 @@ impl fmt::Display for Encoding {
             Compress => "compress",
             Identity => "identity",
             Trailers => "trailers",
+            Zstd => "zstd",
             EncodingExt(ref s) => s.as_ref(),
         })
     }
@@ -52,6 +55,7 @@ impl str::FromStr for Encoding {
             "compress" => Ok(Compress),
             "identity" => Ok(Identity),
             "trailers" => Ok(Trailers),
+            "zstd" => Ok(Zstd),
             _ => Ok(EncodingExt(s.to_owned())),
         }
     }
diff --git a/src/http/header/etag.rs b/src/http/header/etag.rs
index b121fe26f..aded72665 100644
--- a/src/http/header/etag.rs
+++ b/src/http/header/etag.rs
@@ -1,6 +1,6 @@
 use super::{EntityTag, ETAG};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `ETag` header, defined in [RFC7232](http://tools.ietf.org/html/rfc7232#section-2.3)
     ///
     /// The `ETag` header field in a response provides the current entity-tag
@@ -50,50 +50,50 @@ crate::__define_common_header! {
 
     test_etag {
         // From the RFC
-        crate::__common_header_test!(test1,
+        crate::http::header::common_header_test!(test1,
             vec![b"\"xyzzy\""],
             Some(ETag(EntityTag::new(false, "xyzzy".to_owned()))));
-        crate::__common_header_test!(test2,
+        crate::http::header::common_header_test!(test2,
             vec![b"W/\"xyzzy\""],
             Some(ETag(EntityTag::new(true, "xyzzy".to_owned()))));
-        crate::__common_header_test!(test3,
+        crate::http::header::common_header_test!(test3,
             vec![b"\"\""],
             Some(ETag(EntityTag::new(false, "".to_owned()))));
         // Own tests
-        crate::__common_header_test!(test4,
+        crate::http::header::common_header_test!(test4,
             vec![b"\"foobar\""],
             Some(ETag(EntityTag::new(false, "foobar".to_owned()))));
-        crate::__common_header_test!(test5,
+        crate::http::header::common_header_test!(test5,
             vec![b"\"\""],
             Some(ETag(EntityTag::new(false, "".to_owned()))));
-        crate::__common_header_test!(test6,
+        crate::http::header::common_header_test!(test6,
             vec![b"W/\"weak-etag\""],
             Some(ETag(EntityTag::new(true, "weak-etag".to_owned()))));
-        crate::__common_header_test!(test7,
+        crate::http::header::common_header_test!(test7,
             vec![b"W/\"\x65\x62\""],
             Some(ETag(EntityTag::new(true, "\u{0065}\u{0062}".to_owned()))));
-        crate::__common_header_test!(test8,
+        crate::http::header::common_header_test!(test8,
             vec![b"W/\"\""],
             Some(ETag(EntityTag::new(true, "".to_owned()))));
-        crate::__common_header_test!(test9,
+        crate::http::header::common_header_test!(test9,
             vec![b"no-dquotes"],
             None::<ETag>);
-        crate::__common_header_test!(test10,
+        crate::http::header::common_header_test!(test10,
             vec![b"w/\"the-first-w-is-case-sensitive\""],
             None::<ETag>);
-        crate::__common_header_test!(test11,
+        crate::http::header::common_header_test!(test11,
             vec![b""],
             None::<ETag>);
-        crate::__common_header_test!(test12,
+        crate::http::header::common_header_test!(test12,
             vec![b"\"unmatched-dquotes1"],
             None::<ETag>);
-        crate::__common_header_test!(test13,
+        crate::http::header::common_header_test!(test13,
             vec![b"unmatched-dquotes2\""],
             None::<ETag>);
-        crate::__common_header_test!(test14,
+        crate::http::header::common_header_test!(test14,
             vec![b"matched-\"dquotes\""],
             None::<ETag>);
-        crate::__common_header_test!(test15,
+        crate::http::header::common_header_test!(test15,
             vec![b"\""],
             None::<ETag>);
     }
diff --git a/src/http/header/expires.rs b/src/http/header/expires.rs
index 759e7d280..e810fe267 100644
--- a/src/http/header/expires.rs
+++ b/src/http/header/expires.rs
@@ -1,6 +1,6 @@
 use super::{HttpDate, EXPIRES};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Expires` header, defined in [RFC7234](http://tools.ietf.org/html/rfc7234#section-5.3)
     ///
     /// The `Expires` header field gives the date/time after which the
@@ -36,6 +36,6 @@ crate::__define_common_header! {
 
     test_expires {
         // Test case from RFC
-        crate::__common_header_test!(test1, vec![b"Thu, 01 Dec 1994 16:00:00 GMT"]);
+        crate::http::header::common_header_test!(test1, vec![b"Thu, 01 Dec 1994 16:00:00 GMT"]);
     }
 }
diff --git a/src/http/header/if_match.rs b/src/http/header/if_match.rs
index d4402715d..87a94a809 100644
--- a/src/http/header/if_match.rs
+++ b/src/http/header/if_match.rs
@@ -1,6 +1,6 @@
 use super::{EntityTag, IF_MATCH};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `If-Match` header, defined in
     /// [RFC7232](https://tools.ietf.org/html/rfc7232#section-3.1)
     ///
@@ -53,18 +53,18 @@ crate::__define_common_header! {
     (IfMatch, IF_MATCH) => {Any / (EntityTag)+}
 
     test_if_match {
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test1,
             vec![b"\"xyzzy\""],
             Some(HeaderField::Items(
                 vec![EntityTag::new(false, "xyzzy".to_owned())])));
-        crate::__common_header_test!(
+        crate::http::header::common_header_test!(
             test2,
             vec![b"\"xyzzy\", \"r2d2xxxx\", \"c3piozzzz\""],
             Some(HeaderField::Items(
                 vec![EntityTag::new(false, "xyzzy".to_owned()),
                      EntityTag::new(false, "r2d2xxxx".to_owned()),
                      EntityTag::new(false, "c3piozzzz".to_owned())])));
-        crate::__common_header_test!(test3, vec![b"*"], Some(IfMatch::Any));
+        crate::http::header::common_header_test!(test3, vec![b"*"], Some(IfMatch::Any));
     }
 }
diff --git a/src/http/header/if_modified_since.rs b/src/http/header/if_modified_since.rs
index ba393032d..254003523 100644
--- a/src/http/header/if_modified_since.rs
+++ b/src/http/header/if_modified_since.rs
@@ -1,6 +1,6 @@
 use super::{HttpDate, IF_MODIFIED_SINCE};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `If-Modified-Since` header, defined in
     /// [RFC7232](http://tools.ietf.org/html/rfc7232#section-3.3)
     ///
@@ -36,6 +36,6 @@ crate::__define_common_header! {
 
     test_if_modified_since {
         // Test case from RFC
-        crate::__common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
+        crate::http::header::common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
     }
 }
diff --git a/src/http/header/if_none_match.rs b/src/http/header/if_none_match.rs
index f16b196cc..e1422bd36 100644
--- a/src/http/header/if_none_match.rs
+++ b/src/http/header/if_none_match.rs
@@ -1,6 +1,6 @@
 use super::{EntityTag, IF_NONE_MATCH};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `If-None-Match` header, defined in
     /// [RFC7232](https://tools.ietf.org/html/rfc7232#section-3.2)
     ///
@@ -55,11 +55,11 @@ crate::__define_common_header! {
     (IfNoneMatch, IF_NONE_MATCH) => {Any / (EntityTag)+}
 
     test_if_none_match {
-        crate::__common_header_test!(test1, vec![b"\"xyzzy\""]);
-        crate::__common_header_test!(test2, vec![b"W/\"xyzzy\""]);
-        crate::__common_header_test!(test3, vec![b"\"xyzzy\", \"r2d2xxxx\", \"c3piozzzz\""]);
-        crate::__common_header_test!(test4, vec![b"W/\"xyzzy\", W/\"r2d2xxxx\", W/\"c3piozzzz\""]);
-        crate::__common_header_test!(test5, vec![b"*"]);
+        crate::http::header::common_header_test!(test1, vec![b"\"xyzzy\""]);
+        crate::http::header::common_header_test!(test2, vec![b"W/\"xyzzy\""]);
+        crate::http::header::common_header_test!(test3, vec![b"\"xyzzy\", \"r2d2xxxx\", \"c3piozzzz\""]);
+        crate::http::header::common_header_test!(test4, vec![b"W/\"xyzzy\", W/\"r2d2xxxx\", W/\"c3piozzzz\""]);
+        crate::http::header::common_header_test!(test5, vec![b"*"]);
     }
 }
 
diff --git a/src/http/header/if_range.rs b/src/http/header/if_range.rs
index 9612405e8..cf69e7269 100644
--- a/src/http/header/if_range.rs
+++ b/src/http/header/if_range.rs
@@ -113,7 +113,7 @@ mod test_if_range {
     use crate::http::header::*;
     use std::str;
 
-    crate::__common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
-    crate::__common_header_test!(test2, vec![b"\"abc\""]);
-    crate::__common_header_test!(test3, vec![b"this-is-invalid"], None::<IfRange>);
+    crate::http::header::common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
+    crate::http::header::common_header_test!(test2, vec![b"\"abc\""]);
+    crate::http::header::common_header_test!(test3, vec![b"this-is-invalid"], None::<IfRange>);
 }
diff --git a/src/http/header/if_unmodified_since.rs b/src/http/header/if_unmodified_since.rs
index 26b16b513..1cc7b304e 100644
--- a/src/http/header/if_unmodified_since.rs
+++ b/src/http/header/if_unmodified_since.rs
@@ -1,6 +1,6 @@
 use super::{HttpDate, IF_UNMODIFIED_SINCE};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `If-Unmodified-Since` header, defined in
     /// [RFC7232](http://tools.ietf.org/html/rfc7232#section-3.4)
     ///
@@ -37,6 +37,6 @@ crate::__define_common_header! {
 
     test_if_unmodified_since {
         // Test case from RFC
-        crate::__common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
+        crate::http::header::common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
     }
 }
diff --git a/src/http/header/last_modified.rs b/src/http/header/last_modified.rs
index 0de2fc06b..c43bf3ac9 100644
--- a/src/http/header/last_modified.rs
+++ b/src/http/header/last_modified.rs
@@ -1,6 +1,6 @@
 use super::{HttpDate, LAST_MODIFIED};
 
-crate::__define_common_header! {
+crate::http::header::common_header! {
     /// `Last-Modified` header, defined in
     /// [RFC7232](http://tools.ietf.org/html/rfc7232#section-2.2)
     ///
@@ -36,6 +36,6 @@ crate::__define_common_header! {
 
         test_last_modified {
             // Test case from RFC
-            crate::__common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
+            crate::http::header::common_header_test!(test1, vec![b"Sat, 29 Oct 1994 19:43:31 GMT"]);
         }
 }
diff --git a/src/http/header/macros.rs b/src/http/header/macros.rs
index 1718a8663..419d4fb6e 100644
--- a/src/http/header/macros.rs
+++ b/src/http/header/macros.rs
@@ -1,6 +1,4 @@
-#[doc(hidden)]
-#[macro_export]
-macro_rules! __common_header_deref {
+macro_rules! common_header_deref {
     ($from:ty => $to:ty) => {
         impl ::std::ops::Deref for $from {
             type Target = $to;
@@ -20,9 +18,7 @@ macro_rules! __common_header_deref {
     };
 }
 
-#[doc(hidden)]
-#[macro_export]
-macro_rules! __common_header_test_module {
+macro_rules! common_header_test_module {
     ($id:ident, $tm:ident{$($tf:item)*}) => {
         #[allow(unused_imports)]
         #[cfg(test)]
@@ -37,9 +33,8 @@ macro_rules! __common_header_test_module {
     }
 }
 
-#[doc(hidden)]
-#[macro_export]
-macro_rules! __common_header_test {
+#[cfg(test)]
+macro_rules! common_header_test {
     ($id:ident, $raw:expr) => {
         #[test]
         fn $id() {
@@ -99,9 +94,7 @@ macro_rules! __common_header_test {
     };
 }
 
-#[doc(hidden)]
-#[macro_export]
-macro_rules! __define_common_header {
+macro_rules! common_header {
     // $a:meta: Attributes associated with the header item (usually docs)
     // $id:ident: Identifier of the header
     // $n:expr: Lowercase name of the header
@@ -112,7 +105,7 @@ macro_rules! __define_common_header {
         $(#[$a])*
         #[derive(Clone, Debug, PartialEq)]
         pub struct $id(pub Vec<$item>);
-        crate::__common_header_deref!($id => Vec<$item>);
+        crate::http::header::common_header_deref!($id => Vec<$item>);
         impl $crate::http::header::Header for $id {
             #[inline]
             fn name() -> $crate::http::header::HeaderName {
@@ -148,7 +141,7 @@ macro_rules! __define_common_header {
         $(#[$a])*
         #[derive(Clone, Debug, PartialEq)]
         pub struct $id(pub Vec<$item>);
-        crate::__common_header_deref!($id => Vec<$item>);
+        crate::http::header::common_header_deref!($id => Vec<$item>);
         impl $crate::http::header::Header for $id {
             #[inline]
             fn name() -> $crate::http::header::HeaderName {
@@ -184,7 +177,7 @@ macro_rules! __define_common_header {
         $(#[$a])*
         #[derive(Clone, Debug, PartialEq)]
         pub struct $id(pub $value);
-        crate::__common_header_deref!($id => $value);
+        crate::http::header::common_header_deref!($id => $value);
         impl $crate::http::header::Header for $id {
             #[inline]
             fn name() -> $crate::http::header::HeaderName {
@@ -267,34 +260,39 @@ macro_rules! __define_common_header {
 
     // optional test module
     ($(#[$a:meta])*($id:ident, $name:expr) => ($item:ty)* $tm:ident{$($tf:item)*}) => {
-        crate::__define_common_header! {
+        crate::http::header::common_header! {
             $(#[$a])*
             ($id, $name) => ($item)*
         }
 
-        crate::__common_header_test_module! { $id, $tm { $($tf)* }}
+        crate::http::header::common_header_test_module! { $id, $tm { $($tf)* }}
     };
     ($(#[$a:meta])*($id:ident, $n:expr) => ($item:ty)+ $tm:ident{$($tf:item)*}) => {
-        crate::__define_common_header! {
+        crate::http::header::common_header! {
             $(#[$a])*
             ($id, $n) => ($item)+
         }
 
-        crate::__common_header_test_module! { $id, $tm { $($tf)* }}
+        crate::http::header::common_header_test_module! { $id, $tm { $($tf)* }}
     };
     ($(#[$a:meta])*($id:ident, $name:expr) => [$item:ty] $tm:ident{$($tf:item)*}) => {
-        crate::__define_common_header! {
+        crate::http::header::common_header! {
             $(#[$a])* ($id, $name) => [$item]
         }
 
-        crate::__common_header_test_module! { $id, $tm { $($tf)* }}
+        crate::http::header::common_header_test_module! { $id, $tm { $($tf)* }}
     };
     ($(#[$a:meta])*($id:ident, $name:expr) => {Any / ($item:ty)+} $tm:ident{$($tf:item)*}) => {
-        crate::__define_common_header! {
+        crate::http::header::common_header! {
             $(#[$a])*
             ($id, $name) => {Any / ($item)+}
         }
 
-        crate::__common_header_test_module! { $id, $tm { $($tf)* }}
+        crate::http::header::common_header_test_module! { $id, $tm { $($tf)* }}
     };
 }
+
+pub(crate) use {common_header, common_header_deref, common_header_test_module};
+
+#[cfg(test)]
+pub(crate) use common_header_test;
diff --git a/src/http/header/mod.rs b/src/http/header/mod.rs
index 0e5651a77..79ba5772b 100644
--- a/src/http/header/mod.rs
+++ b/src/http/header/mod.rs
@@ -84,4 +84,8 @@ mod if_none_match;
 mod if_range;
 mod if_unmodified_since;
 mod last_modified;
+
 mod macros;
+#[cfg(test)]
+pub(crate) use macros::common_header_test;
+pub(crate) use macros::{common_header, common_header_deref, common_header_test_module};
diff --git a/src/info.rs b/src/info.rs
index c9ddf6ec4..1f8263add 100644
--- a/src/info.rs
+++ b/src/info.rs
@@ -1,13 +1,68 @@
-use std::cell::Ref;
+use std::{cell::Ref, convert::Infallible, net::SocketAddr};
 
-use crate::dev::{AppConfig, RequestHead};
-use crate::http::header::{self, HeaderName};
+use actix_utils::future::{err, ok, Ready};
+use derive_more::{Display, Error};
+use once_cell::sync::Lazy;
 
-const X_FORWARDED_FOR: &[u8] = b"x-forwarded-for";
-const X_FORWARDED_HOST: &[u8] = b"x-forwarded-host";
-const X_FORWARDED_PROTO: &[u8] = b"x-forwarded-proto";
+use crate::{
+    dev::{AppConfig, Payload, RequestHead},
+    http::{
+        header::{self, HeaderName},
+        uri::{Authority, Scheme},
+    },
+    FromRequest, HttpRequest, ResponseError,
+};
 
-/// `HttpRequest` connection information
+static X_FORWARDED_FOR: Lazy<HeaderName> =
+    Lazy::new(|| HeaderName::from_static("x-forwarded-for"));
+static X_FORWARDED_HOST: Lazy<HeaderName> =
+    Lazy::new(|| HeaderName::from_static("x-forwarded-host"));
+static X_FORWARDED_PROTO: Lazy<HeaderName> =
+    Lazy::new(|| HeaderName::from_static("x-forwarded-proto"));
+
+/// Trim whitespace then any quote marks.
+fn unquote(val: &str) -> &str {
+    val.trim().trim_start_matches('"').trim_end_matches('"')
+}
+
+/// Extracts and trims first value for given header name.
+fn first_header_value<'a>(req: &'a RequestHead, name: &'_ HeaderName) -> Option<&'a str> {
+    let hdr = req.headers.get(name)?.to_str().ok()?;
+    let val = hdr.split(',').next()?.trim();
+    Some(val)
+}
+
+/// HTTP connection information.
+///
+/// `ConnectionInfo` implements `FromRequest` and can be extracted in handlers.
+///
+/// # Examples
+/// ```
+/// # use actix_web::{HttpResponse, Responder};
+/// use actix_web::dev::ConnectionInfo;
+///
+/// async fn handler(conn: ConnectionInfo) -> impl Responder {
+///     match conn.host() {
+///         "actix.rs" => HttpResponse::Ok().body("Welcome!"),
+///         "admin.actix.rs" => HttpResponse::Ok().body("Admin portal."),
+///         _ => HttpResponse::NotFound().finish()
+///     }
+/// }
+/// # let _svc = actix_web::web::to(handler);
+/// ```
+///
+/// # Implementation Notes
+/// Parses `Forwarded` header information according to [RFC 7239][rfc7239] but does not try to
+/// interpret the values for each property. As such, the getter methods on `ConnectionInfo` return
+/// strings instead of IP addresses or other types to acknowledge that they may be
+/// [obfuscated][rfc7239-63] or [unknown][rfc7239-62].
+///
+/// If the older, related headers are also present (eg. `X-Forwarded-For`), then `Forwarded`
+/// is preferred.
+///
+/// [rfc7239]: https://datatracker.ietf.org/doc/html/rfc7239
+/// [rfc7239-62]: https://datatracker.ietf.org/doc/html/rfc7239#section-6.2
+/// [rfc7239-63]: https://datatracker.ietf.org/doc/html/rfc7239#section-6.3
 #[derive(Debug, Clone, Default)]
 pub struct ConnectionInfo {
     scheme: String,
@@ -25,105 +80,75 @@ impl ConnectionInfo {
         Ref::map(req.extensions(), |e| e.get().unwrap())
     }
 
-    #[allow(clippy::cognitive_complexity, clippy::borrow_interior_mutable_const)]
     fn new(req: &RequestHead, cfg: &AppConfig) -> ConnectionInfo {
         let mut host = None;
         let mut scheme = None;
         let mut realip_remote_addr = None;
 
-        // load forwarded header
-        for hdr in req.headers.get_all(&header::FORWARDED) {
-            if let Ok(val) = hdr.to_str() {
-                for pair in val.split(';') {
-                    for el in pair.split(',') {
-                        let mut items = el.trim().splitn(2, '=');
-                        if let Some(name) = items.next() {
-                            if let Some(val) = items.next() {
-                                match &name.to_lowercase() as &str {
-                                    "for" => {
-                                        if realip_remote_addr.is_none() {
-                                            realip_remote_addr = Some(val.trim());
-                                        }
-                                    }
-                                    "proto" => {
-                                        if scheme.is_none() {
-                                            scheme = Some(val.trim());
-                                        }
-                                    }
-                                    "host" => {
-                                        if host.is_none() {
-                                            host = Some(val.trim());
-                                        }
-                                    }
-                                    _ => {}
-                                }
-                            }
-                        }
-                    }
+        for (name, val) in req
+            .headers
+            .get_all(&header::FORWARDED)
+            .into_iter()
+            .filter_map(|hdr| hdr.to_str().ok())
+            // "for=1.2.3.4, for=5.6.7.8; scheme=https"
+            .flat_map(|val| val.split(';'))
+            // ["for=1.2.3.4, for=5.6.7.8", " scheme=https"]
+            .flat_map(|vals| vals.split(','))
+            // ["for=1.2.3.4", " for=5.6.7.8", " scheme=https"]
+            .flat_map(|pair| {
+                let mut items = pair.trim().splitn(2, '=');
+                Some((items.next()?, items.next()?))
+            })
+        {
+            // [(name , val      ), ...                                    ]
+            // [("for", "1.2.3.4"), ("for", "5.6.7.8"), ("scheme", "https")]
+
+            // taking the first value for each property is correct because spec states that first
+            // "for" value is client and rest are proxies; multiple values other properties have
+            // no defined semantics
+            //
+            // > In a chain of proxy servers where this is fully utilized, the first
+            // > "for" parameter will disclose the client where the request was first
+            // > made, followed by any subsequent proxy identifiers.
+            // --- https://datatracker.ietf.org/doc/html/rfc7239#section-5.2
+
+            match name.trim().to_lowercase().as_str() {
+                "for" => realip_remote_addr.get_or_insert_with(|| unquote(val)),
+                "proto" => scheme.get_or_insert_with(|| unquote(val)),
+                "host" => host.get_or_insert_with(|| unquote(val)),
+                "by" => {
+                    // TODO: implement https://datatracker.ietf.org/doc/html/rfc7239#section-5.1
+                    continue;
                 }
-            }
+                _ => continue,
+            };
         }
 
-        // scheme
-        if scheme.is_none() {
-            if let Some(h) = req
-                .headers
-                .get(&HeaderName::from_lowercase(X_FORWARDED_PROTO).unwrap())
-            {
-                if let Ok(h) = h.to_str() {
-                    scheme = h.split(',').next().map(|v| v.trim());
-                }
-            }
-            if scheme.is_none() {
-                scheme = req.uri.scheme().map(|a| a.as_str());
-                if scheme.is_none() && cfg.secure() {
-                    scheme = Some("https")
-                }
-            }
-        }
+        let scheme = scheme
+            .or_else(|| first_header_value(req, &*X_FORWARDED_PROTO))
+            .or_else(|| req.uri.scheme().map(Scheme::as_str))
+            .or_else(|| Some("https").filter(|_| cfg.secure()))
+            .unwrap_or("http")
+            .to_owned();
 
-        // host
-        if host.is_none() {
-            if let Some(h) = req
-                .headers
-                .get(&HeaderName::from_lowercase(X_FORWARDED_HOST).unwrap())
-            {
-                if let Ok(h) = h.to_str() {
-                    host = h.split(',').next().map(|v| v.trim());
-                }
-            }
-            if host.is_none() {
-                if let Some(h) = req.headers.get(&header::HOST) {
-                    host = h.to_str().ok();
-                }
-                if host.is_none() {
-                    host = req.uri.authority().map(|a| a.as_str());
-                    if host.is_none() {
-                        host = Some(cfg.host());
-                    }
-                }
-            }
-        }
+        let host = host
+            .or_else(|| first_header_value(req, &*X_FORWARDED_HOST))
+            .or_else(|| req.headers.get(&header::HOST)?.to_str().ok())
+            .or_else(|| req.uri.authority().map(Authority::as_str))
+            .unwrap_or(cfg.host())
+            .to_owned();
 
-        // get remote_addraddr from socketaddr
-        let remote_addr = req.peer_addr.map(|addr| format!("{}", addr));
+        let realip_remote_addr = realip_remote_addr
+            .or_else(|| first_header_value(req, &*X_FORWARDED_FOR))
+            .map(str::to_owned);
 
-        if realip_remote_addr.is_none() {
-            if let Some(h) = req
-                .headers
-                .get(&HeaderName::from_lowercase(X_FORWARDED_FOR).unwrap())
-            {
-                if let Ok(h) = h.to_str() {
-                    realip_remote_addr = h.split(',').next().map(|v| v.trim());
-                }
-            }
-        }
+        let remote_addr = req.peer_addr.map(|addr| addr.to_string());
 
         ConnectionInfo {
             remote_addr,
-            scheme: scheme.unwrap_or("http").to_owned(),
-            host: host.unwrap_or("localhost").to_owned(),
-            realip_remote_addr: realip_remote_addr.map(|s| s.to_owned()),
+            scheme,
+            host,
+            realip_remote_addr,
         }
     }
 
@@ -152,19 +177,16 @@ impl ConnectionInfo {
         &self.host
     }
 
-    /// remote_addr address of the request.
+    /// Remote address of the connection.
     ///
-    /// Get remote_addr address from socket address
+    /// Get remote_addr address from socket address.
     pub fn remote_addr(&self) -> Option<&str> {
-        if let Some(ref remote_addr) = self.remote_addr {
-            Some(remote_addr)
-        } else {
-            None
-        }
+        self.remote_addr.as_deref()
     }
-    /// Real ip remote addr of client initiated HTTP request.
+
+    /// Real IP (remote address) of client that initiated request.
     ///
-    /// The addr is resolved through the following headers, in this order:
+    /// The address is resolved through the following headers, in this order:
     ///
     /// - Forwarded
     /// - X-Forwarded-For
@@ -173,16 +195,72 @@ impl ConnectionInfo {
     /// # Security
     /// Do not use this function for security purposes, unless you can ensure the Forwarded and
     /// X-Forwarded-For headers cannot be spoofed by the client. If you want the client's socket
-    /// address explicitly, use
-    /// [`HttpRequest::peer_addr()`](super::web::HttpRequest::peer_addr()) instead.
+    /// address explicitly, use [`HttpRequest::peer_addr()`][peer_addr] instead.
+    ///
+    /// [peer_addr]: crate::web::HttpRequest::peer_addr()
     #[inline]
     pub fn realip_remote_addr(&self) -> Option<&str> {
-        if let Some(ref r) = self.realip_remote_addr {
-            Some(r)
-        } else if let Some(ref remote_addr) = self.remote_addr {
-            Some(remote_addr)
-        } else {
-            None
+        self.realip_remote_addr
+            .as_deref()
+            .or_else(|| self.remote_addr.as_deref())
+    }
+}
+
+impl FromRequest for ConnectionInfo {
+    type Error = Infallible;
+    type Future = Ready<Result<Self, Self::Error>>;
+    type Config = ();
+
+    fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future {
+        ok(req.connection_info().clone())
+    }
+}
+
+/// Extractor for peer's socket address.
+///
+/// Also see [`HttpRequest::peer_addr`].
+///
+/// # Examples
+/// ```
+/// # use actix_web::Responder;
+/// use actix_web::dev::PeerAddr;
+///
+/// async fn handler(peer_addr: PeerAddr) -> impl Responder {
+///     let socket_addr = peer_addr.0;
+///     socket_addr.to_string()
+/// }
+/// # let _svc = actix_web::web::to(handler);
+/// ```
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Display)]
+#[display(fmt = "{}", _0)]
+pub struct PeerAddr(pub SocketAddr);
+
+impl PeerAddr {
+    /// Unwrap into inner `SocketAddr` value.
+    pub fn into_inner(self) -> SocketAddr {
+        self.0
+    }
+}
+
+#[derive(Debug, Display, Error)]
+#[non_exhaustive]
+#[display(fmt = "Missing peer address")]
+pub struct MissingPeerAddr;
+
+impl ResponseError for MissingPeerAddr {}
+
+impl FromRequest for PeerAddr {
+    type Error = MissingPeerAddr;
+    type Future = Ready<Result<Self, Self::Error>>;
+    type Config = ();
+
+    fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future {
+        match req.peer_addr() {
+            Some(addr) => ok(PeerAddr(addr)),
+            None => {
+                log::error!("Missing peer address.");
+                err(MissingPeerAddr)
+            }
         }
     }
 }
@@ -192,13 +270,60 @@ mod tests {
     use super::*;
     use crate::test::TestRequest;
 
+    const X_FORWARDED_FOR: &str = "x-forwarded-for";
+    const X_FORWARDED_HOST: &str = "x-forwarded-host";
+    const X_FORWARDED_PROTO: &str = "x-forwarded-proto";
+
     #[test]
-    fn test_forwarded() {
+    fn info_default() {
         let req = TestRequest::default().to_http_request();
         let info = req.connection_info();
         assert_eq!(info.scheme(), "http");
         assert_eq!(info.host(), "localhost:8080");
+    }
 
+    #[test]
+    fn host_header() {
+        let req = TestRequest::default()
+            .insert_header((header::HOST, "rust-lang.org"))
+            .to_http_request();
+
+        let info = req.connection_info();
+        assert_eq!(info.scheme(), "http");
+        assert_eq!(info.host(), "rust-lang.org");
+        assert_eq!(info.realip_remote_addr(), None);
+    }
+
+    #[test]
+    fn x_forwarded_for_header() {
+        let req = TestRequest::default()
+            .insert_header((X_FORWARDED_FOR, "192.0.2.60"))
+            .to_http_request();
+        let info = req.connection_info();
+        assert_eq!(info.realip_remote_addr(), Some("192.0.2.60"));
+    }
+
+    #[test]
+    fn x_forwarded_host_header() {
+        let req = TestRequest::default()
+            .insert_header((X_FORWARDED_HOST, "192.0.2.60"))
+            .to_http_request();
+        let info = req.connection_info();
+        assert_eq!(info.host(), "192.0.2.60");
+        assert_eq!(info.realip_remote_addr(), None);
+    }
+
+    #[test]
+    fn x_forwarded_proto_header() {
+        let req = TestRequest::default()
+            .insert_header((X_FORWARDED_PROTO, "https"))
+            .to_http_request();
+        let info = req.connection_info();
+        assert_eq!(info.scheme(), "https");
+    }
+
+    #[test]
+    fn forwarded_header() {
         let req = TestRequest::default()
             .insert_header((
                 header::FORWARDED,
@@ -212,31 +337,118 @@ mod tests {
         assert_eq!(info.realip_remote_addr(), Some("192.0.2.60"));
 
         let req = TestRequest::default()
-            .insert_header((header::HOST, "rust-lang.org"))
+            .insert_header((
+                header::FORWARDED,
+                "for=192.0.2.60; proto=https; by=203.0.113.43; host=rust-lang.org",
+            ))
             .to_http_request();
 
         let info = req.connection_info();
-        assert_eq!(info.scheme(), "http");
+        assert_eq!(info.scheme(), "https");
         assert_eq!(info.host(), "rust-lang.org");
-        assert_eq!(info.realip_remote_addr(), None);
+        assert_eq!(info.realip_remote_addr(), Some("192.0.2.60"));
+    }
 
+    #[test]
+    fn forwarded_case_sensitivity() {
         let req = TestRequest::default()
-            .insert_header((X_FORWARDED_FOR, "192.0.2.60"))
+            .insert_header((header::FORWARDED, "For=192.0.2.60"))
             .to_http_request();
         let info = req.connection_info();
         assert_eq!(info.realip_remote_addr(), Some("192.0.2.60"));
+    }
 
+    #[test]
+    fn forwarded_weird_whitespace() {
         let req = TestRequest::default()
-            .insert_header((X_FORWARDED_HOST, "192.0.2.60"))
+            .insert_header((header::FORWARDED, "for= 1.2.3.4; proto= https"))
             .to_http_request();
         let info = req.connection_info();
-        assert_eq!(info.host(), "192.0.2.60");
-        assert_eq!(info.realip_remote_addr(), None);
+        assert_eq!(info.realip_remote_addr(), Some("1.2.3.4"));
+        assert_eq!(info.scheme(), "https");
 
         let req = TestRequest::default()
-            .insert_header((X_FORWARDED_PROTO, "https"))
+            .insert_header((header::FORWARDED, "  for = 1.2.3.4  "))
+            .to_http_request();
+        let info = req.connection_info();
+        assert_eq!(info.realip_remote_addr(), Some("1.2.3.4"));
+    }
+
+    #[test]
+    fn forwarded_for_quoted() {
+        let req = TestRequest::default()
+            .insert_header((header::FORWARDED, r#"for="192.0.2.60:8080""#))
+            .to_http_request();
+        let info = req.connection_info();
+        assert_eq!(info.realip_remote_addr(), Some("192.0.2.60:8080"));
+    }
+
+    #[test]
+    fn forwarded_for_ipv6() {
+        let req = TestRequest::default()
+            .insert_header((header::FORWARDED, r#"for="[2001:db8:cafe::17]:4711""#))
+            .to_http_request();
+        let info = req.connection_info();
+        assert_eq!(info.realip_remote_addr(), Some("[2001:db8:cafe::17]:4711"));
+    }
+
+    #[test]
+    fn forwarded_for_multiple() {
+        let req = TestRequest::default()
+            .insert_header((header::FORWARDED, "for=192.0.2.60, for=198.51.100.17"))
+            .to_http_request();
+        let info = req.connection_info();
+        // takes the first value
+        assert_eq!(info.realip_remote_addr(), Some("192.0.2.60"));
+    }
+
+    #[test]
+    fn scheme_from_uri() {
+        let req = TestRequest::get()
+            .uri("https://actix.rs/test")
             .to_http_request();
         let info = req.connection_info();
         assert_eq!(info.scheme(), "https");
     }
+
+    #[test]
+    fn host_from_uri() {
+        let req = TestRequest::get()
+            .uri("https://actix.rs/test")
+            .to_http_request();
+        let info = req.connection_info();
+        assert_eq!(info.host(), "actix.rs");
+    }
+
+    #[test]
+    fn host_from_server_hostname() {
+        let mut req = TestRequest::get();
+        req.set_server_hostname("actix.rs");
+        let req = req.to_http_request();
+
+        let info = req.connection_info();
+        assert_eq!(info.host(), "actix.rs");
+    }
+
+    #[actix_rt::test]
+    async fn conn_info_extract() {
+        let req = TestRequest::default()
+            .uri("https://actix.rs/test")
+            .to_http_request();
+        let conn_info = ConnectionInfo::extract(&req).await.unwrap();
+        assert_eq!(conn_info.scheme(), "https");
+        assert_eq!(conn_info.host(), "actix.rs");
+    }
+
+    #[actix_rt::test]
+    async fn peer_addr_extract() {
+        let addr = "127.0.0.1:8080".parse().unwrap();
+        let req = TestRequest::default().peer_addr(addr).to_http_request();
+        let peer_addr = PeerAddr::extract(&req).await.unwrap();
+        assert_eq!(peer_addr, PeerAddr(addr));
+
+        let req = TestRequest::default().to_http_request();
+        let res = PeerAddr::extract(&req).await;
+        assert!(res.is_err());
+    }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 96e6ecbf8..714c759cf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,6 @@
 //! Actix Web is a powerful, pragmatic, and extremely fast web framework for Rust.
 //!
-//! ## Example
-//!
+//! # Examples
 //! ```no_run
 //! use actix_web::{get, web, App, HttpServer, Responder};
 //!
@@ -20,13 +19,12 @@
 //! }
 //! ```
 //!
-//! ## Documentation & Community Resources
-//!
+//! # Documentation & Community Resources
 //! In addition to this API documentation, several other resources are available:
 //!
 //! * [Website & User Guide](https://actix.rs/)
 //! * [Examples Repository](https://github.com/actix/examples)
-//! * [Community Chat on Gitter](https://gitter.im/actix/actix-web)
+//! * [Community Chat on Discord](https://discord.gg/NWpN5mmg3x)
 //!
 //! To get started navigating the API docs, you may consider looking at the following pages first:
 //!
@@ -43,13 +41,12 @@
 //!   structs represent HTTP requests and responses and expose methods for creating, inspecting,
 //!   and otherwise utilizing them.
 //!
-//! ## Features
-//!
+//! # Features
 //! * Supports *HTTP/1.x* and *HTTP/2*
 //! * Streaming and pipelining
 //! * Keep-alive and slow requests handling
 //! * Client/server [WebSockets](https://actix.rs/docs/websockets/) support
-//! * Transparent content compression/decompression (br, gzip, deflate)
+//! * Transparent content compression/decompression (br, gzip, deflate, zstd)
 //! * Powerful [request routing](https://actix.rs/docs/url-dispatch/)
 //! * Multipart streams
 //! * Static assets
@@ -58,10 +55,11 @@
 //! * Includes an async [HTTP client](https://docs.rs/awc/)
 //! * Runs on stable Rust 1.46+
 //!
-//! ## Crate Features
-//!
-//! * `compress` - content encoding compression support (enabled by default)
+//! # Crate Features
 //! * `cookies` - cookies support (enabled by default)
+//! * `compress-brotli` - brotli content encoding compression support (enabled by default)
+//! * `compress-gzip` - gzip and deflate content encoding compression support (enabled by default)
+//! * `compress-zstd` - zstd content encoding compression support (enabled by default)
 //! * `openssl` - HTTPS support via `openssl` crate, supports `HTTP/2`
 //! * `rustls` - HTTPS support via `rustls` crate, supports `HTTP/2`
 //! * `secure-cookies` - secure cookies support
@@ -75,10 +73,12 @@ mod app;
 mod app_service;
 mod config;
 mod data;
+pub mod dev;
 pub mod error;
 mod extract;
 pub mod guard;
 mod handler;
+mod helpers;
 pub mod http;
 mod info;
 pub mod middleware;
@@ -97,7 +97,7 @@ pub(crate) mod types;
 pub mod web;
 
 pub use actix_http::Response as BaseHttpResponse;
-pub use actix_http::{body, Error, HttpMessage, ResponseError};
+pub use actix_http::{body, HttpMessage};
 #[doc(inline)]
 pub use actix_rt as rt;
 pub use actix_web_codegen::*;
@@ -105,7 +105,7 @@ pub use actix_web_codegen::*;
 pub use cookie;
 
 pub use crate::app::App;
-pub use crate::error::Result;
+pub use crate::error::{Error, ResponseError, Result};
 pub use crate::extract::FromRequest;
 pub use crate::request::HttpRequest;
 pub use crate::resource::Resource;
@@ -116,102 +116,3 @@ pub use crate::scope::Scope;
 pub use crate::server::HttpServer;
 // TODO: is exposing the error directly really needed
 pub use crate::types::{Either, EitherExtractError};
-
-pub mod dev {
-    //! The `actix-web` prelude for library developers
-    //!
-    //! The purpose of this module is to alleviate imports of many common actix
-    //! traits by adding a glob import to the top of actix heavy modules:
-    //!
-    //! ```
-    //! # #![allow(unused_imports)]
-    //! use actix_web::dev::*;
-    //! ```
-
-    pub use crate::config::{AppConfig, AppService};
-    #[doc(hidden)]
-    pub use crate::handler::Handler;
-    pub use crate::info::ConnectionInfo;
-    pub use crate::rmap::ResourceMap;
-    pub use crate::service::{HttpServiceFactory, ServiceRequest, ServiceResponse, WebService};
-
-    pub use crate::types::form::UrlEncoded;
-    pub use crate::types::json::JsonBody;
-    pub use crate::types::readlines::Readlines;
-
-    pub use actix_http::body::{Body, BodySize, MessageBody, ResponseBody, SizedStream};
-    #[cfg(feature = "compress")]
-    pub use actix_http::encoding::Decoder as Decompress;
-    pub use actix_http::ResponseBuilder as BaseHttpResponseBuilder;
-    pub use actix_http::{Extensions, Payload, PayloadStream, RequestHead, ResponseHead};
-    pub use actix_router::{Path, ResourceDef, ResourcePath, Url};
-    pub use actix_server::Server;
-    pub use actix_service::{always_ready, forward_ready, Service, Transform};
-
-    pub(crate) fn insert_slash(mut patterns: Vec<String>) -> Vec<String> {
-        for path in &mut patterns {
-            if !path.is_empty() && !path.starts_with('/') {
-                path.insert(0, '/');
-            };
-        }
-        patterns
-    }
-
-    use crate::http::header::ContentEncoding;
-    use actix_http::{Response, ResponseBuilder};
-
-    struct Enc(ContentEncoding);
-
-    /// Helper trait that allows to set specific encoding for response.
-    pub trait BodyEncoding {
-        /// Get content encoding
-        fn get_encoding(&self) -> Option<ContentEncoding>;
-
-        /// Set content encoding
-        fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self;
-    }
-
-    impl BodyEncoding for ResponseBuilder {
-        fn get_encoding(&self) -> Option<ContentEncoding> {
-            self.extensions().get::<Enc>().map(|enc| enc.0)
-        }
-
-        fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
-            self.extensions_mut().insert(Enc(encoding));
-            self
-        }
-    }
-
-    impl<B> BodyEncoding for Response<B> {
-        fn get_encoding(&self) -> Option<ContentEncoding> {
-            self.extensions().get::<Enc>().map(|enc| enc.0)
-        }
-
-        fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
-            self.extensions_mut().insert(Enc(encoding));
-            self
-        }
-    }
-
-    impl BodyEncoding for crate::HttpResponseBuilder {
-        fn get_encoding(&self) -> Option<ContentEncoding> {
-            self.extensions().get::<Enc>().map(|enc| enc.0)
-        }
-
-        fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
-            self.extensions_mut().insert(Enc(encoding));
-            self
-        }
-    }
-
-    impl<B> BodyEncoding for crate::HttpResponse<B> {
-        fn get_encoding(&self) -> Option<ContentEncoding> {
-            self.extensions().get::<Enc>().map(|enc| enc.0)
-        }
-
-        fn encoding(&mut self, encoding: ContentEncoding) -> &mut Self {
-            self.extensions_mut().insert(Enc(encoding));
-            self
-        }
-    }
-}
diff --git a/src/middleware/compat.rs b/src/middleware/compat.rs
index 4f2f2a504..0a6256fe2 100644
--- a/src/middleware/compat.rs
+++ b/src/middleware/compat.rs
@@ -50,7 +50,7 @@ where
     T: Transform<S, Req>,
     T::Future: 'static,
     T::Response: MapServiceResponseBody,
-    Error: From<T::Error>,
+    T::Error: Into<Error>,
 {
     type Response = ServiceResponse;
     type Error = Error;
@@ -75,7 +75,7 @@ impl<S, Req> Service<Req> for CompatMiddleware<S>
 where
     S: Service<Req>,
     S::Response: MapServiceResponseBody,
-    Error: From<S::Error>,
+    S::Error: Into<Error>,
 {
     type Response = ServiceResponse;
     type Error = Error;
@@ -99,12 +99,16 @@ impl<Fut, T, E> Future for CompatMiddlewareFuture<Fut>
 where
     Fut: Future<Output = Result<T, E>>,
     T: MapServiceResponseBody,
-    Error: From<E>,
+    E: Into<Error>,
 {
     type Output = Result<ServiceResponse, Error>;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        let res = ready!(self.project().fut.poll(cx))?;
+        let res = match ready!(self.project().fut.poll(cx)) {
+            Ok(res) => res,
+            Err(err) => return Poll::Ready(Err(err.into())),
+        };
+
         Poll::Ready(Ok(res.map_body()))
     }
 }
@@ -140,7 +144,7 @@ mod tests {
     use crate::{web, App, HttpResponse};
 
     #[actix_rt::test]
-    #[cfg(all(feature = "cookies", feature = "compress"))]
+    #[cfg(all(feature = "cookies", feature = "__compress"))]
     async fn test_scope_middleware() {
         use crate::middleware::Compress;
 
@@ -163,7 +167,7 @@ mod tests {
     }
 
     #[actix_rt::test]
-    #[cfg(all(feature = "cookies", feature = "compress"))]
+    #[cfg(all(feature = "cookies", feature = "__compress"))]
     async fn test_resource_scope_middleware() {
         use crate::middleware::Compress;
 
diff --git a/src/middleware/compress.rs b/src/middleware/compress.rs
index f8514c7cc..a9128bc47 100644
--- a/src/middleware/compress.rs
+++ b/src/middleware/compress.rs
@@ -13,7 +13,6 @@ use actix_http::{
     body::{MessageBody, ResponseBody},
     encoding::Encoder,
     http::header::{ContentEncoding, ACCEPT_ENCODING},
-    Error,
 };
 use actix_service::{Service, Transform};
 use actix_utils::future::{ok, Ready};
@@ -23,6 +22,7 @@ use pin_project::pin_project;
 use crate::{
     dev::BodyEncoding,
     service::{ServiceRequest, ServiceResponse},
+    Error,
 };
 
 /// Middleware for compressing response payloads.
@@ -200,8 +200,7 @@ impl AcceptEncoding {
         let mut encodings = raw
             .replace(' ', "")
             .split(',')
-            .map(|l| AcceptEncoding::new(l))
-            .flatten()
+            .filter_map(|l| AcceptEncoding::new(l))
             .collect::<Vec<_>>();
 
         encodings.sort();
diff --git a/src/middleware/err_handlers.rs b/src/middleware/err_handlers.rs
index 88834f8ce..75cc819bc 100644
--- a/src/middleware/err_handlers.rs
+++ b/src/middleware/err_handlers.rs
@@ -13,8 +13,8 @@ use futures_core::{future::LocalBoxFuture, ready};
 
 use crate::{
     dev::{ServiceRequest, ServiceResponse},
-    error::{Error, Result},
     http::StatusCode,
+    Error, Result,
 };
 
 /// Return type for [`ErrorHandlers`] custom handlers.
diff --git a/src/middleware/mod.rs b/src/middleware/mod.rs
index e24782f07..96a361fcf 100644
--- a/src/middleware/mod.rs
+++ b/src/middleware/mod.rs
@@ -14,7 +14,8 @@ pub use self::err_handlers::{ErrorHandlerResponse, ErrorHandlers};
 pub use self::logger::Logger;
 pub use self::normalize::{NormalizePath, TrailingSlash};
 
-#[cfg(feature = "compress")]
+#[cfg(feature = "__compress")]
 mod compress;
-#[cfg(feature = "compress")]
+
+#[cfg(feature = "__compress")]
 pub use self::compress::Compress;
diff --git a/src/middleware/normalize.rs b/src/middleware/normalize.rs
index ec6c2a344..219af1c6a 100644
--- a/src/middleware/normalize.rs
+++ b/src/middleware/normalize.rs
@@ -137,58 +137,63 @@ where
 
         let original_path = head.uri.path();
 
-        // Either adds a string to the end (duplicates will be removed anyways) or trims all slashes from the end
-        let path = match self.trailing_slash_behavior {
-            TrailingSlash::Always => original_path.to_string() + "/",
-            TrailingSlash::MergeOnly => original_path.to_string(),
-            TrailingSlash::Trim => original_path.trim_end_matches('/').to_string(),
-        };
-
-        // normalize multiple /'s to one /
-        let path = self.merge_slash.replace_all(&path, "/");
-
-        // Ensure root paths are still resolvable. If resulting path is blank after previous step
-        // it means the path was one or more slashes. Reduce to single slash.
-        let path = if path.is_empty() { "/" } else { path.as_ref() };
-
-        // Check whether the path has been changed
-        //
-        // This check was previously implemented as string length comparison
-        //
-        // That approach fails when a trailing slash is added,
-        // and a duplicate slash is removed,
-        // since the length of the strings remains the same
-        //
-        // For example, the path "/v1//s" will be normalized to "/v1/s/"
-        // Both of the paths have the same length,
-        // so the change can not be deduced from the length comparison
-        if path != original_path {
-            let mut parts = head.uri.clone().into_parts();
-            let query = parts.path_and_query.as_ref().and_then(|pq| pq.query());
-
-            let path = if let Some(q) = query {
-                Bytes::from(format!("{}?{}", path, q))
-            } else {
-                Bytes::copy_from_slice(path.as_bytes())
+        // An empty path here means that the URI has no valid path. We skip normalization in this
+        // case, because adding a path can make the URI invalid
+        if !original_path.is_empty() {
+            // Either adds a string to the end (duplicates will be removed anyways) or trims all
+            // slashes from the end
+            let path = match self.trailing_slash_behavior {
+                TrailingSlash::Always => format!("{}/", original_path),
+                TrailingSlash::MergeOnly => original_path.to_string(),
+                TrailingSlash::Trim => original_path.trim_end_matches('/').to_string(),
             };
-            parts.path_and_query = Some(PathAndQuery::from_maybe_shared(path).unwrap());
 
-            let uri = Uri::from_parts(parts).unwrap();
-            req.match_info_mut().get_mut().update(&uri);
-            req.head_mut().uri = uri;
+            // normalize multiple /'s to one /
+            let path = self.merge_slash.replace_all(&path, "/");
+
+            // Ensure root paths are still resolvable. If resulting path is blank after previous
+            // step it means the path was one or more slashes. Reduce to single slash.
+            let path = if path.is_empty() { "/" } else { path.as_ref() };
+
+            // Check whether the path has been changed
+            //
+            // This check was previously implemented as string length comparison
+            //
+            // That approach fails when a trailing slash is added,
+            // and a duplicate slash is removed,
+            // since the length of the strings remains the same
+            //
+            // For example, the path "/v1//s" will be normalized to "/v1/s/"
+            // Both of the paths have the same length,
+            // so the change can not be deduced from the length comparison
+            if path != original_path {
+                let mut parts = head.uri.clone().into_parts();
+                let query = parts.path_and_query.as_ref().and_then(|pq| pq.query());
+
+                let path = match query {
+                    Some(q) => Bytes::from(format!("{}?{}", path, q)),
+                    None => Bytes::copy_from_slice(path.as_bytes()),
+                };
+                parts.path_and_query = Some(PathAndQuery::from_maybe_shared(path).unwrap());
+
+                let uri = Uri::from_parts(parts).unwrap();
+                req.match_info_mut().get_mut().update(&uri);
+                req.head_mut().uri = uri;
+            }
         }
-
         self.service.call(req)
     }
 }
 
 #[cfg(test)]
 mod tests {
+    use actix_http::StatusCode;
     use actix_service::IntoService;
 
     use super::*;
     use crate::{
         dev::ServiceRequest,
+        guard::fn_guard,
         test::{call_service, init_service, TestRequest},
         web, App, HttpResponse,
     };
@@ -199,37 +204,34 @@ mod tests {
             App::new()
                 .wrap(NormalizePath::default())
                 .service(web::resource("/").to(HttpResponse::Ok))
-                .service(web::resource("/v1/something").to(HttpResponse::Ok)),
+                .service(web::resource("/v1/something").to(HttpResponse::Ok))
+                .service(
+                    web::resource("/v2/something")
+                        .guard(fn_guard(|req| req.uri.query() == Some("query=test")))
+                        .to(HttpResponse::Ok),
+                ),
         )
         .await;
 
-        let req = TestRequest::with_uri("/").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
+        let test_uris = vec![
+            "/",
+            "/?query=test",
+            "///",
+            "/v1//something",
+            "/v1//something////",
+            "//v1/something",
+            "//v1//////something",
+            "/v2//something?query=test",
+            "/v2//something////?query=test",
+            "//v2/something?query=test",
+            "//v2//////something?query=test",
+        ];
 
-        let req = TestRequest::with_uri("/?query=test").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
-
-        let req = TestRequest::with_uri("///").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
-
-        let req = TestRequest::with_uri("/v1//something////").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
-
-        let req2 = TestRequest::with_uri("//v1/something").to_request();
-        let res2 = call_service(&app, req2).await;
-        assert!(res2.status().is_success());
-
-        let req3 = TestRequest::with_uri("//v1//////something").to_request();
-        let res3 = call_service(&app, req3).await;
-        assert!(res3.status().is_success());
-
-        let req4 = TestRequest::with_uri("/v1//something").to_request();
-        let res4 = call_service(&app, req4).await;
-        assert!(res4.status().is_success());
+        for uri in test_uris {
+            let req = TestRequest::with_uri(uri).to_request();
+            let res = call_service(&app, req).await;
+            assert!(res.status().is_success(), "Failed uri: {}", uri);
+        }
     }
 
     #[actix_rt::test]
@@ -238,38 +240,114 @@ mod tests {
             App::new()
                 .wrap(NormalizePath(TrailingSlash::Trim))
                 .service(web::resource("/").to(HttpResponse::Ok))
-                .service(web::resource("/v1/something").to(HttpResponse::Ok)),
+                .service(web::resource("/v1/something").to(HttpResponse::Ok))
+                .service(
+                    web::resource("/v2/something")
+                        .guard(fn_guard(|req| req.uri.query() == Some("query=test")))
+                        .to(HttpResponse::Ok),
+                ),
         )
         .await;
 
-        // root paths should still work
-        let req = TestRequest::with_uri("/").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
+        let test_uris = vec![
+            "/",
+            "///",
+            "/v1/something",
+            "/v1/something/",
+            "/v1/something////",
+            "//v1//something",
+            "//v1//something//",
+            "/v2/something?query=test",
+            "/v2/something/?query=test",
+            "/v2/something////?query=test",
+            "//v2//something?query=test",
+            "//v2//something//?query=test",
+        ];
 
-        let req = TestRequest::with_uri("/?query=test").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
+        for uri in test_uris {
+            let req = TestRequest::with_uri(uri).to_request();
+            let res = call_service(&app, req).await;
+            assert!(res.status().is_success(), "Failed uri: {}", uri);
+        }
+    }
 
-        let req = TestRequest::with_uri("///").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
+    #[actix_rt::test]
+    async fn trim_root_trailing_slashes_with_query() {
+        let app = init_service(
+            App::new().wrap(NormalizePath(TrailingSlash::Trim)).service(
+                web::resource("/")
+                    .guard(fn_guard(|req| req.uri.query() == Some("query=test")))
+                    .to(HttpResponse::Ok),
+            ),
+        )
+        .await;
 
-        let req = TestRequest::with_uri("/v1/something////").to_request();
-        let res = call_service(&app, req).await;
-        assert!(res.status().is_success());
+        let test_uris = vec!["/?query=test", "//?query=test", "///?query=test"];
 
-        let req2 = TestRequest::with_uri("/v1/something/").to_request();
-        let res2 = call_service(&app, req2).await;
-        assert!(res2.status().is_success());
+        for uri in test_uris {
+            let req = TestRequest::with_uri(uri).to_request();
+            let res = call_service(&app, req).await;
+            assert!(res.status().is_success(), "Failed uri: {}", uri);
+        }
+    }
 
-        let req3 = TestRequest::with_uri("//v1//something//").to_request();
-        let res3 = call_service(&app, req3).await;
-        assert!(res3.status().is_success());
+    #[actix_rt::test]
+    async fn ensure_trailing_slash() {
+        let app = init_service(
+            App::new()
+                .wrap(NormalizePath(TrailingSlash::Always))
+                .service(web::resource("/").to(HttpResponse::Ok))
+                .service(web::resource("/v1/something/").to(HttpResponse::Ok))
+                .service(
+                    web::resource("/v2/something/")
+                        .guard(fn_guard(|req| req.uri.query() == Some("query=test")))
+                        .to(HttpResponse::Ok),
+                ),
+        )
+        .await;
 
-        let req4 = TestRequest::with_uri("//v1//something").to_request();
-        let res4 = call_service(&app, req4).await;
-        assert!(res4.status().is_success());
+        let test_uris = vec![
+            "/",
+            "///",
+            "/v1/something",
+            "/v1/something/",
+            "/v1/something////",
+            "//v1//something",
+            "//v1//something//",
+            "/v2/something?query=test",
+            "/v2/something/?query=test",
+            "/v2/something////?query=test",
+            "//v2//something?query=test",
+            "//v2//something//?query=test",
+        ];
+
+        for uri in test_uris {
+            let req = TestRequest::with_uri(uri).to_request();
+            let res = call_service(&app, req).await;
+            assert!(res.status().is_success(), "Failed uri: {}", uri);
+        }
+    }
+
+    #[actix_rt::test]
+    async fn ensure_root_trailing_slash_with_query() {
+        let app = init_service(
+            App::new()
+                .wrap(NormalizePath(TrailingSlash::Always))
+                .service(
+                    web::resource("/")
+                        .guard(fn_guard(|req| req.uri.query() == Some("query=test")))
+                        .to(HttpResponse::Ok),
+                ),
+        )
+        .await;
+
+        let test_uris = vec!["/?query=test", "//?query=test", "///?query=test"];
+
+        for uri in test_uris {
+            let req = TestRequest::with_uri(uri).to_request();
+            let res = call_service(&app, req).await;
+            assert!(res.status().is_success(), "Failed uri: {}", uri);
+        }
     }
 
     #[actix_rt::test]
@@ -279,7 +357,12 @@ mod tests {
                 .wrap(NormalizePath(TrailingSlash::MergeOnly))
                 .service(web::resource("/").to(HttpResponse::Ok))
                 .service(web::resource("/v1/something").to(HttpResponse::Ok))
-                .service(web::resource("/v1/").to(HttpResponse::Ok)),
+                .service(web::resource("/v1/").to(HttpResponse::Ok))
+                .service(
+                    web::resource("/v2/something")
+                        .guard(fn_guard(|req| req.uri.query() == Some("query=test")))
+                        .to(HttpResponse::Ok),
+                ),
         )
         .await;
 
@@ -295,15 +378,35 @@ mod tests {
             ("/v1////", true),
             ("//v1//", true),
             ("///v1", false),
+            ("/v2/something?query=test", true),
+            ("/v2/something/?query=test", false),
+            ("/v2/something//?query=test", false),
+            ("//v2//something?query=test", true),
         ];
 
-        for (path, success) in tests {
-            let req = TestRequest::with_uri(path).to_request();
+        for (uri, success) in tests {
+            let req = TestRequest::with_uri(uri).to_request();
             let res = call_service(&app, req).await;
-            assert_eq!(res.status().is_success(), success);
+            assert_eq!(res.status().is_success(), success, "Failed uri: {}", uri);
         }
     }
 
+    #[actix_rt::test]
+    async fn no_path() {
+        let app = init_service(
+            App::new()
+                .wrap(NormalizePath::default())
+                .service(web::resource("/").to(HttpResponse::Ok)),
+        )
+        .await;
+
+        // This URI will be interpreted as an authority form, i.e. there is no path nor scheme
+        // (https://datatracker.ietf.org/doc/html/rfc7230#section-5.3.3)
+        let req = TestRequest::with_uri("eh").to_request();
+        let res = call_service(&app, req).await;
+        assert_eq!(res.status(), StatusCode::NOT_FOUND);
+    }
+
     #[actix_rt::test]
     async fn test_in_place_normalization() {
         let srv = |req: ServiceRequest| {
@@ -316,21 +419,18 @@ mod tests {
             .await
             .unwrap();
 
-        let req = TestRequest::with_uri("/v1//something////").to_srv_request();
-        let res = normalize.call(req).await.unwrap();
-        assert!(res.status().is_success());
+        let test_uris = vec![
+            "/v1//something////",
+            "///v1/something",
+            "//v1///something",
+            "/v1//something",
+        ];
 
-        let req2 = TestRequest::with_uri("///v1/something").to_srv_request();
-        let res2 = normalize.call(req2).await.unwrap();
-        assert!(res2.status().is_success());
-
-        let req3 = TestRequest::with_uri("//v1///something").to_srv_request();
-        let res3 = normalize.call(req3).await.unwrap();
-        assert!(res3.status().is_success());
-
-        let req4 = TestRequest::with_uri("/v1//something").to_srv_request();
-        let res4 = normalize.call(req4).await.unwrap();
-        assert!(res4.status().is_success());
+        for uri in test_uris {
+            let req = TestRequest::with_uri(uri).to_srv_request();
+            let res = normalize.call(req).await.unwrap();
+            assert!(res.status().is_success(), "Failed uri: {}", uri);
+        }
     }
 
     #[actix_rt::test]
diff --git a/src/request.rs b/src/request.rs
index c218388eb..803556e9a 100644
--- a/src/request.rs
+++ b/src/request.rs
@@ -7,7 +7,7 @@ use std::{
 
 use actix_http::{
     http::{HeaderMap, Method, Uri, Version},
-    Error, Extensions, HttpMessage, Message, Payload, RequestHead,
+    Extensions, HttpMessage, Message, Payload, RequestHead,
 };
 use actix_router::{Path, Url};
 use actix_utils::future::{ok, Ready};
@@ -17,7 +17,7 @@ use smallvec::SmallVec;
 
 use crate::{
     app_service::AppInitServiceState, config::AppConfig, error::UrlGenerationError,
-    extract::FromRequest, info::ConnectionInfo, rmap::ResourceMap,
+    info::ConnectionInfo, rmap::ResourceMap, Error, FromRequest,
 };
 
 #[cfg(feature = "cookies")]
@@ -60,18 +60,6 @@ impl HttpRequest {
             }),
         }
     }
-
-    #[doc(hidden)]
-    pub fn __priv_test_new(
-        path: Path<Url>,
-        head: Message<RequestHead>,
-        rmap: Rc<ResourceMap>,
-        config: AppConfig,
-        app_data: Rc<Extensions>,
-    ) -> HttpRequest {
-        let app_state = AppInitServiceState::new(rmap, config);
-        Self::new(path, head, app_state, app_data)
-    }
 }
 
 impl HttpRequest {
@@ -123,11 +111,7 @@ impl HttpRequest {
     /// E.g., id=10
     #[inline]
     pub fn query_string(&self) -> &str {
-        if let Some(query) = self.uri().query().as_ref() {
-            query
-        } else {
-            ""
-        }
+        self.uri().query().unwrap_or_default()
     }
 
     /// Get a reference to the Path parameters.
@@ -356,11 +340,10 @@ impl Drop for HttpRequest {
 
 /// It is possible to get `HttpRequest` as an extractor handler parameter
 ///
-/// ## Example
-///
+/// # Examples
 /// ```
 /// use actix_web::{web, App, HttpRequest};
-/// use serde_derive::Deserialize;
+/// use serde::Deserialize;
 ///
 /// /// extract `Thing` from request
 /// async fn index(req: HttpRequest) -> String {
@@ -723,6 +706,8 @@ mod tests {
         assert_eq!(body, Bytes::from_static(b"1"));
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_extensions_dropped() {
         struct Tracker {
diff --git a/src/request_data.rs b/src/request_data.rs
index 6558cbb37..575dc1eb3 100644
--- a/src/request_data.rs
+++ b/src/request_data.rs
@@ -1,9 +1,8 @@
 use std::{any::type_name, ops::Deref};
 
-use actix_http::error::Error;
 use actix_utils::future::{err, ok, Ready};
 
-use crate::{dev::Payload, error::ErrorInternalServerError, FromRequest, HttpRequest};
+use crate::{dev::Payload, error::ErrorInternalServerError, Error, FromRequest, HttpRequest};
 
 /// Request-local data extractor.
 ///
diff --git a/src/resource.rs b/src/resource.rs
index e90ad2dd9..4e609f31a 100644
--- a/src/resource.rs
+++ b/src/resource.rs
@@ -3,7 +3,7 @@ use std::fmt;
 use std::future::Future;
 use std::rc::Rc;
 
-use actix_http::{Error, Extensions};
+use actix_http::Extensions;
 use actix_router::IntoPattern;
 use actix_service::boxed::{self, BoxService, BoxServiceFactory};
 use actix_service::{
@@ -13,14 +13,16 @@ use actix_service::{
 use futures_core::future::LocalBoxFuture;
 use futures_util::future::join_all;
 
-use crate::dev::{insert_slash, AppService, HttpServiceFactory, ResourceDef};
-use crate::extract::FromRequest;
-use crate::guard::Guard;
-use crate::handler::Handler;
-use crate::responder::Responder;
-use crate::route::{Route, RouteService};
-use crate::service::{ServiceRequest, ServiceResponse};
-use crate::{data::Data, HttpResponse};
+use crate::{
+    data::Data,
+    dev::{insert_slash, AppService, HttpServiceFactory, ResourceDef},
+    guard::Guard,
+    handler::Handler,
+    responder::Responder,
+    route::{Route, RouteService},
+    service::{ServiceRequest, ServiceResponse},
+    Error, FromRequest, HttpResponse,
+};
 
 type HttpService = BoxService<ServiceRequest, ServiceResponse, Error>;
 type HttpNewService = BoxServiceFactory<(), ServiceRequest, ServiceResponse, Error, ()>;
@@ -167,38 +169,38 @@ where
         self
     }
 
-    /// Provide resource specific data. This method allows to add extractor
-    /// configuration or specific state available via `Data<T>` extractor.
-    /// Provided data is available for all routes registered for the current resource.
-    /// Resource data overrides data registered by `App::data()` method.
-    ///
-    /// ```
-    /// use actix_web::{web, App};
-    ///
-    /// /// extract text data from request
-    /// async fn index(body: String) -> String {
-    ///     format!("Body {}!", body)
-    /// }
-    ///
-    /// fn main() {
-    ///     let app = App::new().service(
-    ///         web::resource("/index.html")
-    ///           // limit size of the payload
-    ///           .data(web::PayloadConfig::new(4096))
-    ///           .route(
-    ///               web::get()
-    ///                  // register handler
-    ///                  .to(index)
-    ///           ));
-    /// }
-    /// ```
-    pub fn data<U: 'static>(self, data: U) -> Self {
-        self.app_data(Data::new(data))
-    }
-
     /// Add resource data.
     ///
-    /// Data of different types from parent contexts will still be accessible.
+    /// Data of different types from parent contexts will still be accessible. Any `Data<T>` types
+    /// set here can be extracted in handlers using the `Data<T>` extractor.
+    ///
+    /// # Examples
+    /// ```
+    /// use std::cell::Cell;
+    /// use actix_web::{web, App, HttpRequest, HttpResponse, Responder};
+    ///
+    /// struct MyData {
+    ///     count: std::cell::Cell<usize>,
+    /// }
+    ///
+    /// async fn handler(req: HttpRequest, counter: web::Data<MyData>) -> impl Responder {
+    ///     // note this cannot use the Data<T> extractor because it was not added with it
+    ///     let incr = *req.app_data::<usize>().unwrap();
+    ///     assert_eq!(incr, 3);
+    ///
+    ///     // update counter using other value from app data
+    ///     counter.count.set(counter.count.get() + incr);
+    ///
+    ///     HttpResponse::Ok().body(counter.count.get().to_string())
+    /// }
+    ///
+    /// let app = App::new().service(
+    ///     web::resource("/")
+    ///         .app_data(3usize)
+    ///         .app_data(web::Data::new(MyData { count: Default::default() }))
+    ///         .route(web::get().to(handler))
+    /// );
+    /// ```
     pub fn app_data<U: 'static>(mut self, data: U) -> Self {
         self.app_data
             .get_or_insert_with(Extensions::new)
@@ -207,6 +209,14 @@ where
         self
     }
 
+    /// Add resource data after wrapping in `Data<T>`.
+    ///
+    /// Deprecated in favor of [`app_data`](Self::app_data).
+    #[deprecated(since = "4.0.0", note = "Use `.app_data(Data::new(val))` instead.")]
+    pub fn data<U: 'static>(self, data: U) -> Self {
+        self.app_data(Data::new(data))
+    }
+
     /// Register a new route and add handler. This route matches all requests.
     ///
     /// ```
@@ -222,7 +232,6 @@ where
     /// This is shortcut for:
     ///
     /// ```
-    /// # extern crate actix_web;
     /// # use actix_web::*;
     /// # fn index(req: HttpRequest) -> HttpResponse { unimplemented!() }
     /// App::new().service(web::resource("/").route(web::route().to(index)));
@@ -391,34 +400,28 @@ where
             *rdef.name_mut() = name.clone();
         }
 
-        config.register_service(rdef, guards, self, None)
-    }
-}
-
-impl<T> IntoServiceFactory<T, ServiceRequest> for Resource<T>
-where
-    T: ServiceFactory<
-        ServiceRequest,
-        Config = (),
-        Response = ServiceResponse,
-        Error = Error,
-        InitError = (),
-    >,
-{
-    fn into_factory(self) -> T {
         *self.factory_ref.borrow_mut() = Some(ResourceFactory {
             routes: self.routes,
-            app_data: self.app_data.map(Rc::new),
             default: self.default,
         });
 
-        self.endpoint
+        let resource_data = self.app_data.map(Rc::new);
+
+        // wraps endpoint service (including middleware) call and injects app data for this scope
+        let endpoint = apply_fn_factory(self.endpoint, move |mut req: ServiceRequest, srv| {
+            if let Some(ref data) = resource_data {
+                req.add_data_container(Rc::clone(data));
+            }
+
+            srv.call(req)
+        });
+
+        config.register_service(rdef, guards, endpoint, None)
     }
 }
 
 pub struct ResourceFactory {
     routes: Vec<Route>,
-    app_data: Option<Rc<Extensions>>,
     default: HttpNewService,
 }
 
@@ -437,8 +440,6 @@ impl ServiceFactory<ServiceRequest> for ResourceFactory {
         // construct route service factory futures
         let factory_fut = join_all(self.routes.iter().map(|route| route.new_service(())));
 
-        let app_data = self.app_data.clone();
-
         Box::pin(async move {
             let default = default_fut.await?;
             let routes = factory_fut
@@ -446,18 +447,13 @@ impl ServiceFactory<ServiceRequest> for ResourceFactory {
                 .into_iter()
                 .collect::<Result<Vec<_>, _>>()?;
 
-            Ok(ResourceService {
-                routes,
-                app_data,
-                default,
-            })
+            Ok(ResourceService { routes, default })
         })
     }
 }
 
 pub struct ResourceService {
     routes: Vec<RouteService>,
-    app_data: Option<Rc<Extensions>>,
     default: HttpService,
 }
 
@@ -469,20 +465,12 @@ impl Service<ServiceRequest> for ResourceService {
     actix_service::always_ready!();
 
     fn call(&self, mut req: ServiceRequest) -> Self::Future {
-        for route in self.routes.iter() {
+        for route in &self.routes {
             if route.check(&mut req) {
-                if let Some(ref app_data) = self.app_data {
-                    req.add_data_container(app_data.clone());
-                }
-
                 return route.call(req);
             }
         }
 
-        if let Some(ref app_data) = self.app_data {
-            req.add_data_container(app_data.clone());
-        }
-
         self.default.call(req)
     }
 }
@@ -519,11 +507,14 @@ mod tests {
     use actix_service::Service;
     use actix_utils::future::ok;
 
-    use crate::http::{header, HeaderValue, Method, StatusCode};
-    use crate::middleware::DefaultHeaders;
-    use crate::service::ServiceRequest;
-    use crate::test::{call_service, init_service, TestRequest};
-    use crate::{guard, web, App, Error, HttpResponse};
+    use crate::{
+        guard,
+        http::{header, HeaderValue, Method, StatusCode},
+        middleware::DefaultHeaders,
+        service::{ServiceRequest, ServiceResponse},
+        test::{call_service, init_service, TestRequest},
+        web, App, Error, HttpMessage, HttpResponse,
+    };
 
     #[actix_rt::test]
     async fn test_middleware() {
@@ -690,6 +681,8 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::NO_CONTENT);
     }
 
+    // allow deprecated `{App, Resource}::data`
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_data() {
         let srv = init_service(
@@ -722,6 +715,8 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::OK);
     }
 
+    // allow deprecated `{App, Resource}::data`
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_data_default_service() {
         let srv = init_service(
@@ -740,4 +735,39 @@ mod tests {
         let resp = call_service(&srv, req).await;
         assert_eq!(resp.status(), StatusCode::OK);
     }
+
+    #[actix_rt::test]
+    async fn test_middleware_app_data() {
+        let srv = init_service(
+            App::new().service(
+                web::resource("test")
+                    .app_data(1usize)
+                    .wrap_fn(|req, srv| {
+                        assert_eq!(req.app_data::<usize>(), Some(&1usize));
+                        req.extensions_mut().insert(1usize);
+                        srv.call(req)
+                    })
+                    .route(web::get().to(HttpResponse::Ok))
+                    .default_service(|req: ServiceRequest| async move {
+                        let (req, _) = req.into_parts();
+
+                        assert_eq!(req.extensions().get::<usize>(), Some(&1));
+
+                        Ok(ServiceResponse::new(
+                            req,
+                            HttpResponse::BadRequest().finish(),
+                        ))
+                    }),
+            ),
+        )
+        .await;
+
+        let req = TestRequest::get().uri("/test").to_request();
+        let resp = call_service(&srv, req).await;
+        assert_eq!(resp.status(), StatusCode::OK);
+
+        let req = TestRequest::post().uri("/test").to_request();
+        let resp = call_service(&srv, req).await;
+        assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
+    }
 }
diff --git a/src/responder.rs b/src/responder.rs
index 8bf8d9ea0..c5852a501 100644
--- a/src/responder.rs
+++ b/src/responder.rs
@@ -1,4 +1,4 @@
-use std::{borrow::Cow, fmt};
+use std::borrow::Cow;
 
 use actix_http::{
     body::Body,
@@ -6,7 +6,7 @@ use actix_http::{
 };
 use bytes::{Bytes, BytesMut};
 
-use crate::{error::InternalError, Error, HttpRequest, HttpResponse, HttpResponseBuilder};
+use crate::{Error, HttpRequest, HttpResponse, HttpResponseBuilder};
 
 /// Trait implemented by types that can be converted to an HTTP response.
 ///
@@ -226,15 +226,6 @@ impl<T: Responder> Responder for CustomResponder<T> {
     }
 }
 
-impl<T> Responder for InternalError<T>
-where
-    T: fmt::Debug + fmt::Display + 'static,
-{
-    fn respond_to(self, _: &HttpRequest) -> HttpResponse {
-        HttpResponse::from_error(self.into())
-    }
-}
-
 #[cfg(test)]
 pub(crate) mod tests {
     use actix_service::Service;
diff --git a/src/response/builder.rs b/src/response/builder.rs
index b9a10c56b..56d30d9d0 100644
--- a/src/response/builder.rs
+++ b/src/response/builder.rs
@@ -1,13 +1,14 @@
 use std::{
     cell::{Ref, RefMut},
     convert::TryInto,
+    error::Error as StdError,
     future::Future,
     pin::Pin,
     task::{Context, Poll},
 };
 
 use actix_http::{
-    body::{Body, BodyStream},
+    body::{AnyBody, BodyStream},
     http::{
         header::{self, HeaderName, IntoHeaderPair, IntoHeaderValue},
         ConnectionType, Error as HttpError, StatusCode,
@@ -32,7 +33,7 @@ use crate::{
 ///
 /// This type can be used to construct an instance of `Response` through a builder-like pattern.
 pub struct HttpResponseBuilder {
-    res: Option<Response<Body>>,
+    res: Option<Response<AnyBody>>,
     err: Option<HttpError>,
     #[cfg(feature = "cookies")]
     cookies: Option<CookieJar>,
@@ -310,7 +311,7 @@ impl HttpResponseBuilder {
     ///
     /// `HttpResponseBuilder` can not be used after this call.
     #[inline]
-    pub fn body<B: Into<Body>>(&mut self, body: B) -> HttpResponse<Body> {
+    pub fn body<B: Into<AnyBody>>(&mut self, body: B) -> HttpResponse<AnyBody> {
         match self.message_body(body.into()) {
             Ok(res) => res,
             Err(err) => HttpResponse::from_error(err),
@@ -354,9 +355,9 @@ impl HttpResponseBuilder {
     pub fn streaming<S, E>(&mut self, stream: S) -> HttpResponse
     where
         S: Stream<Item = Result<Bytes, E>> + Unpin + 'static,
-        E: Into<Error> + 'static,
+        E: Into<Box<dyn StdError>> + 'static,
     {
-        self.body(Body::from_message(BodyStream::new(stream)))
+        self.body(AnyBody::from_message(BodyStream::new(stream)))
     }
 
     /// Set a json body and generate `Response`
@@ -375,9 +376,9 @@ impl HttpResponseBuilder {
                     self.insert_header((header::CONTENT_TYPE, mime::APPLICATION_JSON));
                 }
 
-                self.body(Body::from(body))
+                self.body(AnyBody::from(body))
             }
-            Err(err) => HttpResponse::from_error(JsonPayloadError::Serialize(err).into()),
+            Err(err) => HttpResponse::from_error(JsonPayloadError::Serialize(err)),
         }
     }
 
@@ -386,7 +387,7 @@ impl HttpResponseBuilder {
     /// `HttpResponseBuilder` can not be used after this call.
     #[inline]
     pub fn finish(&mut self) -> HttpResponse {
-        self.body(Body::Empty)
+        self.body(AnyBody::Empty)
     }
 
     /// This method construct new `HttpResponseBuilder`
@@ -405,7 +406,7 @@ impl HttpResponseBuilder {
             return None;
         }
 
-        self.res.as_mut().map(|res| res.head_mut())
+        self.res.as_mut().map(Response::head_mut)
     }
 }
 
@@ -415,7 +416,7 @@ impl From<HttpResponseBuilder> for HttpResponse {
     }
 }
 
-impl From<HttpResponseBuilder> for Response<Body> {
+impl From<HttpResponseBuilder> for Response<AnyBody> {
     fn from(mut builder: HttpResponseBuilder) -> Self {
         builder.finish().into()
     }
diff --git a/src/response/response.rs b/src/response/response.rs
index 194e2dff8..9a3bb2874 100644
--- a/src/response/response.rs
+++ b/src/response/response.rs
@@ -8,7 +8,7 @@ use std::{
 };
 
 use actix_http::{
-    body::{Body, MessageBody},
+    body::{AnyBody, Body, MessageBody},
     http::{header::HeaderMap, StatusCode},
     Extensions, Response, ResponseHead,
 };
@@ -25,12 +25,12 @@ use {
 use crate::{error::Error, HttpResponseBuilder};
 
 /// An HTTP Response
-pub struct HttpResponse<B = Body> {
+pub struct HttpResponse<B = AnyBody> {
     res: Response<B>,
     pub(crate) error: Option<Error>,
 }
 
-impl HttpResponse<Body> {
+impl HttpResponse<AnyBody> {
     /// Create HTTP response builder with specific status.
     #[inline]
     pub fn build(status: StatusCode) -> HttpResponseBuilder {
@@ -48,13 +48,11 @@ impl HttpResponse<Body> {
 
     /// Create an error response.
     #[inline]
-    pub fn from_error(error: Error) -> Self {
-        let res = error.as_response_error().error_response();
-
-        Self {
-            res,
-            error: Some(error),
-        }
+    pub fn from_error(error: impl Into<Error>) -> Self {
+        let error = error.into();
+        let mut response = error.as_response_error().error_response();
+        response.error = Some(error);
+        response
     }
 }
 
@@ -238,7 +236,6 @@ impl<B> HttpResponse<B> {
 impl<B> fmt::Debug for HttpResponse<B>
 where
     B: MessageBody,
-    B::Error: Into<Error>,
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("HttpResponse")
diff --git a/src/route.rs b/src/route.rs
index 0a297b456..d85b940bd 100644
--- a/src/route.rs
+++ b/src/route.rs
@@ -2,19 +2,19 @@
 
 use std::{future::Future, rc::Rc};
 
-use actix_http::{http::Method, Error};
+use actix_http::http::Method;
 use actix_service::{
     boxed::{self, BoxService, BoxServiceFactory},
-    Service, ServiceFactory,
+    Service, ServiceFactory, ServiceFactoryExt,
 };
 use futures_core::future::LocalBoxFuture;
 
-use crate::extract::FromRequest;
-use crate::guard::{self, Guard};
-use crate::handler::{Handler, HandlerService};
-use crate::responder::Responder;
-use crate::service::{ServiceRequest, ServiceResponse};
-use crate::HttpResponse;
+use crate::{
+    guard::{self, Guard},
+    handler::{Handler, HandlerService},
+    service::{ServiceRequest, ServiceResponse},
+    Error, FromRequest, HttpResponse, Responder,
+};
 
 /// Resource route definition
 ///
@@ -128,9 +128,10 @@ impl Route {
 
     /// Set handler function, use request extractors for parameters.
     ///
+    /// # Examples
     /// ```
     /// use actix_web::{web, http, App};
-    /// use serde_derive::Deserialize;
+    /// use serde::Deserialize;
     ///
     /// #[derive(Deserialize)]
     /// struct Info {
@@ -154,7 +155,7 @@ impl Route {
     ///
     /// ```
     /// # use std::collections::HashMap;
-    /// # use serde_derive::Deserialize;
+    /// # use serde::Deserialize;
     /// use actix_web::{web, App};
     ///
     /// #[derive(Deserialize)]
@@ -184,17 +185,67 @@ impl Route {
         self.service = boxed::factory(HandlerService::new(handler));
         self
     }
+
+    /// Set raw service to be constructed and called as the request handler.
+    ///
+    /// # Examples
+    /// ```
+    /// # use std::convert::Infallible;
+    /// # use futures_util::future::LocalBoxFuture;
+    /// # use actix_web::{*, dev::*, http::header};
+    /// struct HelloWorld;
+    ///
+    /// impl Service<ServiceRequest> for HelloWorld {
+    ///     type Response = ServiceResponse;
+    ///     type Error = Infallible;
+    ///     type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
+    ///
+    ///     always_ready!();
+    ///
+    ///     fn call(&self, req: ServiceRequest) -> Self::Future {
+    ///         let (req, _) = req.into_parts();
+    ///
+    ///         let res = HttpResponse::Ok()
+    ///             .insert_header(header::ContentType::plaintext())
+    ///             .body("Hello world!");
+    ///
+    ///         Box::pin(async move { Ok(ServiceResponse::new(req, res)) })
+    ///     }
+    /// }
+    ///
+    /// App::new().route(
+    ///     "/",
+    ///     web::get().service(fn_factory(|| async { Ok(HelloWorld) })),
+    /// );
+    /// ```
+    pub fn service<S, E>(mut self, service_factory: S) -> Self
+    where
+        S: ServiceFactory<
+                ServiceRequest,
+                Response = ServiceResponse,
+                Error = E,
+                InitError = (),
+                Config = (),
+            > + 'static,
+        E: Into<Error> + 'static,
+    {
+        self.service = boxed::factory(service_factory.map_err(Into::into));
+        self
+    }
 }
 
 #[cfg(test)]
 mod tests {
-    use std::time::Duration;
+    use std::{convert::Infallible, time::Duration};
 
     use actix_rt::time::sleep;
     use bytes::Bytes;
-    use serde_derive::Serialize;
+    use futures_core::future::LocalBoxFuture;
+    use serde::Serialize;
 
-    use crate::http::{Method, StatusCode};
+    use crate::dev::{always_ready, fn_factory, fn_service, Service};
+    use crate::http::{header, Method, StatusCode};
+    use crate::service::{ServiceRequest, ServiceResponse};
     use crate::test::{call_service, init_service, read_body, TestRequest};
     use crate::{error, web, App, HttpResponse};
 
@@ -215,7 +266,7 @@ mod tests {
                         }))
                         .route(web::post().to(|| async {
                             sleep(Duration::from_millis(100)).await;
-                            Ok::<_, ()>(HttpResponse::Created())
+                            Ok::<_, Infallible>(HttpResponse::Created())
                         }))
                         .route(web::delete().to(|| async {
                             sleep(Duration::from_millis(100)).await;
@@ -268,4 +319,65 @@ mod tests {
         let body = read_body(resp).await;
         assert_eq!(body, Bytes::from_static(b"{\"name\":\"test\"}"));
     }
+
+    #[actix_rt::test]
+    async fn test_service_handler() {
+        struct HelloWorld;
+
+        impl Service<ServiceRequest> for HelloWorld {
+            type Response = ServiceResponse;
+            type Error = crate::Error;
+            type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+            always_ready!();
+
+            fn call(&self, req: ServiceRequest) -> Self::Future {
+                let (req, _) = req.into_parts();
+
+                let res = HttpResponse::Ok()
+                    .insert_header(header::ContentType::plaintext())
+                    .body("Hello world!");
+
+                Box::pin(async move { Ok(ServiceResponse::new(req, res)) })
+            }
+        }
+
+        let srv = init_service(
+            App::new()
+                .route(
+                    "/hello",
+                    web::get().service(fn_factory(|| async { Ok(HelloWorld) })),
+                )
+                .route(
+                    "/bye",
+                    web::get().service(fn_factory(|| async {
+                        Ok::<_, ()>(fn_service(|req: ServiceRequest| async {
+                            let (req, _) = req.into_parts();
+
+                            let res = HttpResponse::Ok()
+                                .insert_header(header::ContentType::plaintext())
+                                .body("Goodbye, and thanks for all the fish!");
+
+                            Ok::<_, Infallible>(ServiceResponse::new(req, res))
+                        }))
+                    })),
+                ),
+        )
+        .await;
+
+        let req = TestRequest::get().uri("/hello").to_request();
+        let resp = call_service(&srv, req).await;
+        assert_eq!(resp.status(), StatusCode::OK);
+        let body = read_body(resp).await;
+        assert_eq!(body, Bytes::from_static(b"Hello world!"));
+
+        let req = TestRequest::get().uri("/bye").to_request();
+        let resp = call_service(&srv, req).await;
+        assert_eq!(resp.status(), StatusCode::OK);
+        let body = read_body(resp).await;
+        assert_eq!(
+            body,
+            Bytes::from_static(b"Goodbye, and thanks for all the fish!")
+        );
+    }
 }
diff --git a/src/scope.rs b/src/scope.rs
index 412c01d95..aa546c422 100644
--- a/src/scope.rs
+++ b/src/scope.rs
@@ -1,28 +1,23 @@
-use std::cell::RefCell;
-use std::fmt;
-use std::future::Future;
-use std::rc::Rc;
+use std::{cell::RefCell, fmt, future::Future, mem, rc::Rc};
 
 use actix_http::Extensions;
 use actix_router::{ResourceDef, Router};
-use actix_service::boxed::{self, BoxService, BoxServiceFactory};
 use actix_service::{
-    apply, apply_fn_factory, IntoServiceFactory, Service, ServiceFactory, ServiceFactoryExt,
-    Transform,
+    apply, apply_fn_factory,
+    boxed::{self, BoxService, BoxServiceFactory},
+    IntoServiceFactory, Service, ServiceFactory, ServiceFactoryExt, Transform,
 };
 use futures_core::future::LocalBoxFuture;
 use futures_util::future::join_all;
 
-use crate::config::ServiceConfig;
-use crate::data::Data;
-use crate::dev::{AppService, HttpServiceFactory};
-use crate::error::Error;
-use crate::guard::Guard;
-use crate::resource::Resource;
-use crate::rmap::ResourceMap;
-use crate::route::Route;
-use crate::service::{
-    AppServiceFactory, ServiceFactoryWrapper, ServiceRequest, ServiceResponse,
+use crate::{
+    config::ServiceConfig,
+    data::Data,
+    dev::{AppService, HttpServiceFactory},
+    guard::Guard,
+    rmap::ResourceMap,
+    service::{AppServiceFactory, ServiceFactoryWrapper, ServiceRequest, ServiceResponse},
+    Error, Resource, Route,
 };
 
 type Guards = Vec<Box<dyn Guard>>;
@@ -71,16 +66,17 @@ pub struct Scope<T = ScopeEndpoint> {
 impl Scope {
     /// Create a new scope
     pub fn new(path: &str) -> Scope {
-        let fref = Rc::new(RefCell::new(None));
+        let factory_ref = Rc::new(RefCell::new(None));
+
         Scope {
-            endpoint: ScopeEndpoint::new(fref.clone()),
+            endpoint: ScopeEndpoint::new(Rc::clone(&factory_ref)),
             rdef: path.to_string(),
             app_data: None,
             guards: Vec::new(),
             services: Vec::new(),
             default: None,
             external: Vec::new(),
-            factory_ref: fref,
+            factory_ref,
         }
     }
 }
@@ -120,39 +116,38 @@ where
         self
     }
 
-    /// Set or override application data. Application data could be accessed
-    /// by using `Data<T>` extractor where `T` is data type.
-    ///
-    /// ```
-    /// use std::cell::Cell;
-    /// use actix_web::{web, App, HttpResponse, Responder};
-    ///
-    /// struct MyData {
-    ///     counter: Cell<usize>,
-    /// }
-    ///
-    /// async fn index(data: web::Data<MyData>) -> impl Responder {
-    ///     data.counter.set(data.counter.get() + 1);
-    ///     HttpResponse::Ok()
-    /// }
-    ///
-    /// fn main() {
-    ///     let app = App::new().service(
-    ///         web::scope("/app")
-    ///             .data(MyData{ counter: Cell::new(0) })
-    ///             .service(
-    ///                 web::resource("/index.html").route(
-    ///                     web::get().to(index)))
-    ///     );
-    /// }
-    /// ```
-    pub fn data<U: 'static>(self, data: U) -> Self {
-        self.app_data(Data::new(data))
-    }
-
     /// Add scope data.
     ///
-    /// Data of different types from parent contexts will still be accessible.
+    /// Data of different types from parent contexts will still be accessible. Any `Data<T>` types
+    /// set here can be extracted in handlers using the `Data<T>` extractor.
+    ///
+    /// # Examples
+    /// ```
+    /// use std::cell::Cell;
+    /// use actix_web::{web, App, HttpRequest, HttpResponse, Responder};
+    ///
+    /// struct MyData {
+    ///     count: std::cell::Cell<usize>,
+    /// }
+    ///
+    /// async fn handler(req: HttpRequest, counter: web::Data<MyData>) -> impl Responder {
+    ///     // note this cannot use the Data<T> extractor because it was not added with it
+    ///     let incr = *req.app_data::<usize>().unwrap();
+    ///     assert_eq!(incr, 3);
+    ///
+    ///     // update counter using other value from app data
+    ///     counter.count.set(counter.count.get() + incr);
+    ///
+    ///     HttpResponse::Ok().body(counter.count.get().to_string())
+    /// }
+    ///
+    /// let app = App::new().service(
+    ///     web::scope("/app")
+    ///         .app_data(3usize)
+    ///         .app_data(web::Data::new(MyData { count: Default::default() }))
+    ///         .route("/", web::get().to(handler))
+    /// );
+    /// ```
     pub fn app_data<U: 'static>(mut self, data: U) -> Self {
         self.app_data
             .get_or_insert_with(Extensions::new)
@@ -161,15 +156,20 @@ where
         self
     }
 
-    /// Run external configuration as part of the scope building
-    /// process
+    /// Add scope data after wrapping in `Data<T>`.
     ///
-    /// This function is useful for moving parts of configuration to a
-    /// different module or even library. For example,
-    /// some of the resource's configuration could be moved to different module.
+    /// Deprecated in favor of [`app_data`](Self::app_data).
+    #[deprecated(since = "4.0.0", note = "Use `.app_data(Data::new(val))` instead.")]
+    pub fn data<U: 'static>(self, data: U) -> Self {
+        self.app_data(Data::new(data))
+    }
+
+    /// Run external configuration as part of the scope building process.
+    ///
+    /// This function is useful for moving parts of configuration to a different module or library.
+    /// For example, some of the resource's configuration could be moved to different module.
     ///
     /// ```
-    /// # extern crate actix_web;
     /// use actix_web::{web, middleware, App, HttpResponse};
     ///
     /// // this function could be located in different module
@@ -190,18 +190,21 @@ where
     ///         .route("/index.html", web::get().to(|| HttpResponse::Ok()));
     /// }
     /// ```
-    pub fn configure<F>(mut self, f: F) -> Self
+    pub fn configure<F>(mut self, cfg_fn: F) -> Self
     where
         F: FnOnce(&mut ServiceConfig),
     {
         let mut cfg = ServiceConfig::new();
-        f(&mut cfg);
+        cfg_fn(&mut cfg);
+
         self.services.extend(cfg.services);
         self.external.extend(cfg.external);
 
+        // TODO: add Extensions::is_empty check and conditionally insert data
         self.app_data
             .get_or_insert_with(Extensions::new)
             .extend(cfg.app_data);
+
         self
     }
 
@@ -418,13 +421,12 @@ where
         let mut rmap = ResourceMap::new(ResourceDef::root_prefix(&self.rdef));
 
         // external resources
-        for mut rdef in std::mem::take(&mut self.external) {
+        for mut rdef in mem::take(&mut self.external) {
             rmap.add(&mut rdef, None);
         }
 
         // complete scope pipeline creation
         *self.factory_ref.borrow_mut() = Some(ScopeFactory {
-            app_data: self.app_data.take().map(Rc::new),
             default,
             services: cfg
                 .into_services()
@@ -446,18 +448,28 @@ where
             Some(self.guards)
         };
 
+        let scope_data = self.app_data.map(Rc::new);
+
+        // wraps endpoint service (including middleware) call and injects app data for this scope
+        let endpoint = apply_fn_factory(self.endpoint, move |mut req: ServiceRequest, srv| {
+            if let Some(ref data) = scope_data {
+                req.add_data_container(Rc::clone(data));
+            }
+
+            srv.call(req)
+        });
+
         // register final service
         config.register_service(
             ResourceDef::root_prefix(&self.rdef),
             guards,
-            self.endpoint,
+            endpoint,
             Some(Rc::new(rmap)),
         )
     }
 }
 
 pub struct ScopeFactory {
-    app_data: Option<Rc<Extensions>>,
     services: Rc<[(ResourceDef, HttpNewService, RefCell<Option<Guards>>)]>,
     default: Rc<HttpNewService>,
 }
@@ -485,8 +497,6 @@ impl ServiceFactory<ServiceRequest> for ScopeFactory {
             }
         }));
 
-        let app_data = self.app_data.clone();
-
         Box::pin(async move {
             let default = default_fut.await?;
 
@@ -502,17 +512,12 @@ impl ServiceFactory<ServiceRequest> for ScopeFactory {
                 })
                 .finish();
 
-            Ok(ScopeService {
-                app_data,
-                router,
-                default,
-            })
+            Ok(ScopeService { router, default })
         })
     }
 }
 
 pub struct ScopeService {
-    app_data: Option<Rc<Extensions>>,
     router: Router<HttpService, Vec<Box<dyn Guard>>>,
     default: HttpService,
 }
@@ -536,10 +541,6 @@ impl Service<ServiceRequest> for ScopeService {
             true
         });
 
-        if let Some(ref app_data) = self.app_data {
-            req.add_data_container(app_data.clone());
-        }
-
         if let Some((srv, _info)) = res {
             srv.call(req)
         } else {
@@ -578,12 +579,15 @@ mod tests {
     use actix_utils::future::ok;
     use bytes::Bytes;
 
-    use crate::dev::Body;
-    use crate::http::{header, HeaderValue, Method, StatusCode};
-    use crate::middleware::DefaultHeaders;
-    use crate::service::ServiceRequest;
-    use crate::test::{call_service, init_service, read_body, TestRequest};
-    use crate::{guard, web, App, HttpRequest, HttpResponse};
+    use crate::{
+        dev::Body,
+        guard,
+        http::{header, HeaderValue, Method, StatusCode},
+        middleware::DefaultHeaders,
+        service::{ServiceRequest, ServiceResponse},
+        test::{call_service, init_service, read_body, TestRequest},
+        web, App, HttpMessage, HttpRequest, HttpResponse,
+    };
 
     #[actix_rt::test]
     async fn test_scope() {
@@ -915,10 +919,7 @@ mod tests {
     async fn test_default_resource_propagation() {
         let srv = init_service(
             App::new()
-                .service(
-                    web::scope("/app1")
-                        .default_service(web::resource("").to(HttpResponse::BadRequest)),
-                )
+                .service(web::scope("/app1").default_service(web::to(HttpResponse::BadRequest)))
                 .service(web::scope("/app2"))
                 .default_service(|r: ServiceRequest| {
                     ok(r.into_response(HttpResponse::MethodNotAllowed()))
@@ -990,6 +991,43 @@ mod tests {
         );
     }
 
+    #[actix_rt::test]
+    async fn test_middleware_app_data() {
+        let srv = init_service(
+            App::new().service(
+                web::scope("app")
+                    .app_data(1usize)
+                    .wrap_fn(|req, srv| {
+                        assert_eq!(req.app_data::<usize>(), Some(&1usize));
+                        req.extensions_mut().insert(1usize);
+                        srv.call(req)
+                    })
+                    .route("/test", web::get().to(HttpResponse::Ok))
+                    .default_service(|req: ServiceRequest| async move {
+                        let (req, _) = req.into_parts();
+
+                        assert_eq!(req.extensions().get::<usize>(), Some(&1));
+
+                        Ok(ServiceResponse::new(
+                            req,
+                            HttpResponse::BadRequest().finish(),
+                        ))
+                    }),
+            ),
+        )
+        .await;
+
+        let req = TestRequest::with_uri("/app/test").to_request();
+        let resp = call_service(&srv, req).await;
+        assert_eq!(resp.status(), StatusCode::OK);
+
+        let req = TestRequest::with_uri("/app/default").to_request();
+        let resp = call_service(&srv, req).await;
+        assert_eq!(resp.status(), StatusCode::BAD_REQUEST);
+    }
+
+    // allow deprecated {App, Scope}::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_override_data() {
         let srv = init_service(App::new().data(1usize).service(
@@ -1008,6 +1046,8 @@ mod tests {
         assert_eq!(resp.status(), StatusCode::OK);
     }
 
+    // allow deprecated `{App, Scope}::data`
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_override_data_default_service() {
         let srv = init_service(App::new().data(1usize).service(
diff --git a/src/server.rs b/src/server.rs
index 44ae6f880..804b3e367 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -1,23 +1,25 @@
 use std::{
     any::Any,
-    cmp, fmt, io,
+    cmp,
+    error::Error as StdError,
+    fmt, io,
     marker::PhantomData,
     net,
     sync::{Arc, Mutex},
 };
 
-use actix_http::{
-    body::MessageBody, Error, Extensions, HttpService, KeepAlive, Request, Response,
-};
+use actix_http::{body::MessageBody, Extensions, HttpService, KeepAlive, Request, Response};
 use actix_server::{Server, ServerBuilder};
-use actix_service::{map_config, IntoServiceFactory, Service, ServiceFactory};
+use actix_service::{
+    map_config, IntoServiceFactory, Service, ServiceFactory, ServiceFactoryExt as _,
+};
 
 #[cfg(feature = "openssl")]
 use actix_tls::accept::openssl::{AlpnError, SslAcceptor, SslAcceptorBuilder};
 #[cfg(feature = "rustls")]
 use actix_tls::accept::rustls::ServerConfig as RustlsServerConfig;
 
-use crate::config::AppConfig;
+use crate::{config::AppConfig, Error};
 
 struct Socket {
     scheme: &'static str,
@@ -81,7 +83,7 @@ where
     S::Service: 'static,
     // S::Service: 'static,
     B: MessageBody + 'static,
-    B::Error: Into<Error>,
+    B::Error: Into<Box<dyn StdError>>,
 {
     /// Create new HTTP server with application factory
     pub fn new(factory: F) -> Self {
@@ -290,18 +292,22 @@ where
                     let c = cfg.lock().unwrap();
                     let host = c.host.clone().unwrap_or_else(|| format!("{}", addr));
 
-                    let svc = HttpService::build()
+                    let mut svc = HttpService::build()
                         .keep_alive(c.keep_alive)
                         .client_timeout(c.client_timeout)
                         .local_addr(addr);
 
-                    let svc = if let Some(handler) = on_connect_fn.clone() {
-                        svc.on_connect_ext(move |io: &_, ext: _| (handler)(io as &dyn Any, ext))
-                    } else {
-                        svc
+                    if let Some(handler) = on_connect_fn.clone() {
+                        svc = svc.on_connect_ext(move |io: &_, ext: _| {
+                            (handler)(io as &dyn Any, ext)
+                        })
                     };
 
-                    svc.finish(map_config(factory(), move |_| {
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
+                    svc.finish(map_config(fac, move |_| {
                         AppConfig::new(false, host.clone(), addr)
                     }))
                     .tcp()
@@ -356,7 +362,11 @@ where
                         svc
                     };
 
-                    svc.finish(map_config(factory(), move |_| {
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
+                    svc.finish(map_config(fac, move |_| {
                         AppConfig::new(true, host.clone(), addr)
                     }))
                     .openssl(acceptor.clone())
@@ -368,7 +378,7 @@ where
     #[cfg(feature = "rustls")]
     /// Use listener for accepting incoming tls connection requests
     ///
-    /// This method sets alpn protocols to "h2" and "http/1.1"
+    /// This method prepends alpn protocols "h2" and "http/1.1" to configured ones
     pub fn listen_rustls(
         self,
         lst: net::TcpListener,
@@ -410,7 +420,11 @@ where
                         svc
                     };
 
-                    svc.finish(map_config(factory(), move |_| {
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());
+
+                    svc.finish(map_config(fac, move |_| {
                         AppConfig::new(true, host.clone(), addr)
                     }))
                     .rustls(config.clone())
@@ -447,17 +461,15 @@ where
             }
         }
 
-        if !success {
-            if let Some(e) = err.take() {
-                Err(e)
-            } else {
-                Err(io::Error::new(
-                    io::ErrorKind::Other,
-                    "Can not bind to address.",
-                ))
-            }
-        } else {
+        if success {
             Ok(sockets)
+        } else if let Some(e) = err.take() {
+            Err(e)
+        } else {
+            Err(io::Error::new(
+                io::ErrorKind::Other,
+                "Can not bind to address.",
+            ))
         }
     }
 
@@ -482,7 +494,7 @@ where
     #[cfg(feature = "rustls")]
     /// Start listening for incoming tls connections.
     ///
-    /// This method sets alpn protocols to "h2" and "http/1.1"
+    /// This method prepends alpn protocols "h2" and "http/1.1" to configured ones
     pub fn bind_rustls<A: net::ToSocketAddrs>(
         mut self,
         addr: A,
@@ -523,17 +535,20 @@ where
             );
 
             fn_service(|io: UnixStream| async { Ok((io, Protocol::Http1, None)) }).and_then({
-                let svc = HttpService::build()
+                let mut svc = HttpService::build()
                     .keep_alive(c.keep_alive)
                     .client_timeout(c.client_timeout);
 
-                let svc = if let Some(handler) = on_connect_fn.clone() {
-                    svc.on_connect_ext(move |io: &_, ext: _| (&*handler)(io as &dyn Any, ext))
-                } else {
-                    svc
-                };
+                if let Some(handler) = on_connect_fn.clone() {
+                    svc = svc
+                        .on_connect_ext(move |io: &_, ext: _| (&*handler)(io as &dyn Any, ext));
+                }
 
-                svc.finish(map_config(factory(), move |_| config.clone()))
+                let fac = factory()
+                    .into_factory()
+                    .map_err(|err| err.into().error_response());
+
+                svc.finish(map_config(fac, move |_| config.clone()))
             })
         })?;
         Ok(self)
@@ -568,14 +583,20 @@ where
                     c.host.clone().unwrap_or_else(|| format!("{}", socket_addr)),
                     socket_addr,
                 );
+
+                let fac = factory()
+                    .into_factory()
+                    .map_err(|err| err.into().error_response());
+
                 fn_service(|io: UnixStream| async { Ok((io, Protocol::Http1, None)) }).and_then(
                     HttpService::build()
                         .keep_alive(c.keep_alive)
                         .client_timeout(c.client_timeout)
-                        .finish(map_config(factory(), move |_| config.clone())),
+                        .finish(map_config(fac, move |_| config.clone())),
                 )
             },
         )?;
+
         Ok(self)
     }
 }
diff --git a/src/service.rs b/src/service.rs
index b7f244797..c1bffac49 100644
--- a/src/service.rs
+++ b/src/service.rs
@@ -2,24 +2,23 @@ use std::cell::{Ref, RefMut};
 use std::rc::Rc;
 use std::{fmt, net};
 
-use actix_http::body::{Body, MessageBody};
-use actix_http::http::{HeaderMap, Method, StatusCode, Uri, Version};
 use actix_http::{
-    Error, Extensions, HttpMessage, Payload, PayloadStream, RequestHead, Response, ResponseHead,
+    body::{AnyBody, MessageBody},
+    http::{HeaderMap, Method, StatusCode, Uri, Version},
+    Extensions, HttpMessage, Payload, PayloadStream, RequestHead, Response, ResponseHead,
 };
 use actix_router::{IntoPattern, Path, Resource, ResourceDef, Url};
 use actix_service::{IntoServiceFactory, ServiceFactory};
 #[cfg(feature = "cookies")]
 use cookie::{Cookie, ParseError as CookieParseError};
 
-use crate::dev::insert_slash;
-use crate::guard::Guard;
-use crate::info::ConnectionInfo;
-use crate::request::HttpRequest;
-use crate::rmap::ResourceMap;
 use crate::{
     config::{AppConfig, AppService},
-    HttpResponse,
+    dev::insert_slash,
+    guard::Guard,
+    info::ConnectionInfo,
+    rmap::ResourceMap,
+    Error, HttpRequest, HttpResponse,
 };
 
 pub trait HttpServiceFactory {
@@ -74,18 +73,18 @@ impl ServiceRequest {
         Self { req, payload }
     }
 
-    /// Construct service request.
-    #[doc(hidden)]
-    pub fn __priv_test_new(req: HttpRequest, payload: Payload) -> Self {
-        Self::new(req, payload)
-    }
-
     /// Deconstruct request into parts
     #[inline]
     pub fn into_parts(self) -> (HttpRequest, Payload) {
         (self.req, self.payload)
     }
 
+    /// Get mutable access to inner `HttpRequest` and `Payload`
+    #[inline]
+    pub fn parts_mut(&mut self) -> (&mut HttpRequest, &mut Payload) {
+        (&mut self.req, &mut self.payload)
+    }
+
     /// Construct request from parts.
     pub fn from_parts(req: HttpRequest, payload: Payload) -> Self {
         Self { req, payload }
@@ -168,11 +167,7 @@ impl ServiceRequest {
     /// E.g., id=10
     #[inline]
     pub fn query_string(&self) -> &str {
-        if let Some(query) = self.uri().query().as_ref() {
-            query
-        } else {
-            ""
-        }
+        self.uri().query().unwrap_or_default()
     }
 
     /// Peer socket address.
@@ -330,15 +325,15 @@ impl fmt::Debug for ServiceRequest {
     }
 }
 
-pub struct ServiceResponse<B = Body> {
+pub struct ServiceResponse<B = AnyBody> {
     request: HttpRequest,
     response: HttpResponse<B>,
 }
 
-impl ServiceResponse<Body> {
+impl ServiceResponse<AnyBody> {
     /// Create service response from the error
     pub fn from_err<E: Into<Error>>(err: E, request: HttpRequest) -> Self {
-        let response = HttpResponse::from_error(err.into());
+        let response = HttpResponse::from_error(err);
         ServiceResponse { request, response }
     }
 }
@@ -655,6 +650,8 @@ mod tests {
         assert_eq!(resp.status(), http::StatusCode::NOT_FOUND);
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_service_data() {
         let srv =
diff --git a/src/test.rs b/src/test.rs
index de97dc8aa..634826d19 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -613,6 +613,11 @@ impl TestRequest {
         let req = self.to_request();
         call_service(app, req).await
     }
+
+    #[cfg(test)]
+    pub fn set_server_hostname(&mut self, host: &str) {
+        self.config.set_host(host)
+    }
 }
 
 #[cfg(test)]
@@ -839,6 +844,8 @@ mod tests {
         assert!(res.status().is_success());
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_server_data() {
         async fn handler(data: web::Data<usize>) -> impl Responder {
diff --git a/src/types/form.rs b/src/types/form.rs
index d999b35d8..b618dc616 100644
--- a/src/types/form.rs
+++ b/src/types/form.rs
@@ -1,6 +1,7 @@
 //! For URL encoded form helper documentation, see [`Form`].
 
 use std::{
+    borrow::Cow,
     fmt,
     future::Future,
     ops,
@@ -16,7 +17,7 @@ use futures_core::{future::LocalBoxFuture, ready};
 use futures_util::{FutureExt as _, StreamExt as _};
 use serde::{de::DeserializeOwned, Serialize};
 
-#[cfg(feature = "compress")]
+#[cfg(feature = "__compress")]
 use crate::dev::Decompress;
 use crate::{
     error::UrlencodedError, extract::FromRequest, http::header::CONTENT_LENGTH, web, Error,
@@ -80,6 +81,10 @@ use crate::{
 ///     })
 /// }
 /// ```
+///
+/// # Panics
+/// URL encoded forms consist of unordered `key=value` pairs, therefore they cannot be decoded into
+/// any type which depends upon data ordering (eg. tuples). Trying to do so will result in a panic.
 #[derive(PartialEq, Eq, PartialOrd, Ord, Debug)]
 pub struct Form<T>(pub T);
 
@@ -180,7 +185,7 @@ impl<T: Serialize> Responder for Form<T> {
             Ok(body) => HttpResponse::Ok()
                 .content_type(mime::APPLICATION_WWW_FORM_URLENCODED)
                 .body(body),
-            Err(err) => HttpResponse::from_error(UrlencodedError::Serialize(err).into()),
+            Err(err) => HttpResponse::from_error(UrlencodedError::Serialize(err)),
         }
     }
 }
@@ -259,9 +264,9 @@ impl Default for FormConfig {
 /// - content type is not `application/x-www-form-urlencoded`
 /// - content length is greater than [limit](UrlEncoded::limit())
 pub struct UrlEncoded<T> {
-    #[cfg(feature = "compress")]
+    #[cfg(feature = "__compress")]
     stream: Option<Decompress<Payload>>,
-    #[cfg(not(feature = "compress"))]
+    #[cfg(not(feature = "__compress"))]
     stream: Option<Payload>,
 
     limit: usize,
@@ -297,10 +302,15 @@ impl<T> UrlEncoded<T> {
             }
         };
 
-        #[cfg(feature = "compress")]
-        let payload = Decompress::from_headers(payload.take(), req.headers());
-        #[cfg(not(feature = "compress"))]
-        let payload = payload.take();
+        let payload = {
+            cfg_if::cfg_if! {
+                if #[cfg(feature = "__compress")] {
+                    Decompress::from_headers(payload.take(), req.headers())
+                } else {
+                    payload.take()
+                }
+            }
+        };
 
         UrlEncoded {
             encoding,
@@ -379,7 +389,7 @@ where
                 } else {
                     let body = encoding
                         .decode_without_bom_handling_and_without_replacement(&body)
-                        .map(|s| s.into_owned())
+                        .map(Cow::into_owned)
                         .ok_or(UrlencodedError::Encoding)?;
 
                     serde_urlencoded::from_str::<T>(&body).map_err(UrlencodedError::Parse)
diff --git a/src/types/json.rs b/src/types/json.rs
index 5b2bda5fd..2bf953183 100644
--- a/src/types/json.rs
+++ b/src/types/json.rs
@@ -16,7 +16,7 @@ use serde::{de::DeserializeOwned, Serialize};
 
 use actix_http::Payload;
 
-#[cfg(feature = "compress")]
+#[cfg(feature = "__compress")]
 use crate::dev::Decompress;
 use crate::{
     error::{Error, JsonPayloadError},
@@ -127,7 +127,7 @@ impl<T: Serialize> Responder for Json<T> {
             Ok(body) => HttpResponse::Ok()
                 .content_type(mime::APPLICATION_JSON)
                 .body(body),
-            Err(err) => HttpResponse::from_error(JsonPayloadError::Serialize(err).into()),
+            Err(err) => HttpResponse::from_error(JsonPayloadError::Serialize(err)),
         }
     }
 }
@@ -239,7 +239,7 @@ pub struct JsonConfig {
 }
 
 impl JsonConfig {
-    /// Set maximum accepted payload size. By default this limit is 32kB.
+    /// Set maximum accepted payload size. By default this limit is 2MB.
     pub fn limit(mut self, limit: usize) -> Self {
         self.limit = limit;
         self
@@ -272,9 +272,11 @@ impl JsonConfig {
     }
 }
 
+const DEFAULT_LIMIT: usize = 2_097_152; // 2 mb
+
 /// Allow shared refs used as default.
 const DEFAULT_CONFIG: JsonConfig = JsonConfig {
-    limit: 32_768, // 2^15 bytes, (~32kB)
+    limit: DEFAULT_LIMIT,
     err_handler: None,
     content_type: None,
 };
@@ -297,9 +299,9 @@ pub enum JsonBody<T> {
     Body {
         limit: usize,
         length: Option<usize>,
-        #[cfg(feature = "compress")]
+        #[cfg(feature = "__compress")]
         payload: Decompress<Payload>,
-        #[cfg(not(feature = "compress"))]
+        #[cfg(not(feature = "__compress"))]
         payload: Payload,
         buf: BytesMut,
         _res: PhantomData<T>,
@@ -342,13 +344,18 @@ where
         // As the internal usage always call JsonBody::limit after JsonBody::new.
         // And limit check to return an error variant of JsonBody happens there.
 
-        #[cfg(feature = "compress")]
-        let payload = Decompress::from_headers(payload.take(), req.headers());
-        #[cfg(not(feature = "compress"))]
-        let payload = payload.take();
+        let payload = {
+            cfg_if::cfg_if! {
+                if #[cfg(feature = "__compress")] {
+                    Decompress::from_headers(payload.take(), req.headers())
+                } else {
+                    payload.take()
+                }
+            }
+        };
 
         JsonBody::Body {
-            limit: 32_768,
+            limit: DEFAULT_LIMIT,
             length,
             payload,
             buf: BytesMut::with_capacity(8192),
@@ -356,7 +363,7 @@ where
         }
     }
 
-    /// Set maximum accepted payload size. The default limit is 32kB.
+    /// Set maximum accepted payload size. The default limit is 2MB.
     pub fn limit(self, limit: usize) -> Self {
         match self {
             JsonBody::Body {
@@ -367,7 +374,10 @@ where
             } => {
                 if let Some(len) = length {
                     if len > limit {
-                        return JsonBody::Error(Some(JsonPayloadError::Overflow));
+                        return JsonBody::Error(Some(JsonPayloadError::OverflowKnownLength {
+                            length: len,
+                            limit,
+                        }));
                     }
                 }
 
@@ -404,8 +414,11 @@ where
                 match res {
                     Some(chunk) => {
                         let chunk = chunk?;
-                        if (buf.len() + chunk.len()) > *limit {
-                            return Poll::Ready(Err(JsonPayloadError::Overflow));
+                        let buf_len = buf.len() + chunk.len();
+                        if buf_len > *limit {
+                            return Poll::Ready(Err(JsonPayloadError::Overflow {
+                                limit: *limit,
+                            }));
                         } else {
                             buf.extend_from_slice(&chunk);
                         }
@@ -444,7 +457,12 @@ mod tests {
 
     fn json_eq(err: JsonPayloadError, other: JsonPayloadError) -> bool {
         match err {
-            JsonPayloadError::Overflow => matches!(other, JsonPayloadError::Overflow),
+            JsonPayloadError::Overflow { .. } => {
+                matches!(other, JsonPayloadError::Overflow { .. })
+            }
+            JsonPayloadError::OverflowKnownLength { .. } => {
+                matches!(other, JsonPayloadError::OverflowKnownLength { .. })
+            }
             JsonPayloadError::ContentType => matches!(other, JsonPayloadError::ContentType),
             _ => false,
         }
@@ -486,7 +504,7 @@ mod tests {
                 };
                 let resp =
                     HttpResponse::BadRequest().body(serde_json::to_string(&msg).unwrap());
-                InternalError::from_response(err, resp.into()).into()
+                InternalError::from_response(err, resp).into()
             }))
             .to_http_parts();
 
@@ -537,7 +555,7 @@ mod tests {
 
         let s = Json::<MyObject>::from_request(&req, &mut pl).await;
         assert!(format!("{}", s.err().unwrap())
-            .contains("Json payload size is bigger than allowed"));
+            .contains("JSON payload (16 bytes) is larger than allowed (limit: 10 bytes)."));
 
         let (req, mut pl) = TestRequest::default()
             .insert_header((
@@ -588,7 +606,30 @@ mod tests {
         let json = JsonBody::<MyObject>::new(&req, &mut pl, None)
             .limit(100)
             .await;
-        assert!(json_eq(json.err().unwrap(), JsonPayloadError::Overflow));
+        assert!(json_eq(
+            json.err().unwrap(),
+            JsonPayloadError::OverflowKnownLength {
+                length: 10000,
+                limit: 100
+            }
+        ));
+
+        let (req, mut pl) = TestRequest::default()
+            .insert_header((
+                header::CONTENT_TYPE,
+                header::HeaderValue::from_static("application/json"),
+            ))
+            .set_payload(Bytes::from_static(&[0u8; 1000]))
+            .to_http_parts();
+
+        let json = JsonBody::<MyObject>::new(&req, &mut pl, None)
+            .limit(100)
+            .await;
+
+        assert!(json_eq(
+            json.err().unwrap(),
+            JsonPayloadError::Overflow { limit: 100 }
+        ));
 
         let (req, mut pl) = TestRequest::default()
             .insert_header((
@@ -685,6 +726,7 @@ mod tests {
         assert!(s.is_err());
 
         let err_str = s.err().unwrap().to_string();
-        assert!(err_str.contains("Json payload size is bigger than allowed"));
+        assert!(err_str
+            .contains("JSON payload (16 bytes) is larger than allowed (limit: 10 bytes)."));
     }
 }
diff --git a/src/types/path.rs b/src/types/path.rs
index a47801b3f..ebccf323e 100644
--- a/src/types/path.rs
+++ b/src/types/path.rs
@@ -2,14 +2,13 @@
 
 use std::{fmt, ops, sync::Arc};
 
-use actix_http::error::Error;
 use actix_router::PathDeserializer;
 use actix_utils::future::{ready, Ready};
 use serde::de;
 
 use crate::{
     dev::Payload,
-    error::{ErrorNotFound, PathError},
+    error::{Error, ErrorNotFound, PathError},
     FromRequest, HttpRequest,
 };
 
@@ -103,8 +102,7 @@ where
     fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future {
         let error_handler = req
             .app_data::<PathConfig>()
-            .map(|c| c.ehandler.clone())
-            .unwrap_or(None);
+            .and_then(|c| c.ehandler.clone());
 
         ready(
             de::Deserialize::deserialize(PathDeserializer::new(req.match_info()))
@@ -295,11 +293,8 @@ mod tests {
     async fn test_custom_err_handler() {
         let (req, mut pl) = TestRequest::with_uri("/name/user1/")
             .app_data(PathConfig::default().error_handler(|err, _| {
-                error::InternalError::from_response(
-                    err,
-                    HttpResponse::Conflict().finish().into(),
-                )
-                .into()
+                error::InternalError::from_response(err, HttpResponse::Conflict().finish())
+                    .into()
             }))
             .to_http_parts();
 
diff --git a/src/types/payload.rs b/src/types/payload.rs
index 7af4db0b1..46ad96beb 100644
--- a/src/types/payload.rs
+++ b/src/types/payload.rs
@@ -1,6 +1,7 @@
 //! Basic binary and string payload extractors.
 
 use std::{
+    borrow::Cow,
     future::Future,
     pin::Pin,
     str,
@@ -186,7 +187,7 @@ fn bytes_to_string(body: Bytes, encoding: &'static Encoding) -> Result<String, E
     } else {
         Ok(encoding
             .decode_without_bom_handling_and_without_replacement(&body)
-            .map(|s| s.into_owned())
+            .map(Cow::into_owned)
             .ok_or_else(|| ErrorBadRequest("Can not decode body"))?)
     }
 }
@@ -279,9 +280,9 @@ impl Default for PayloadConfig {
 pub struct HttpMessageBody {
     limit: usize,
     length: Option<usize>,
-    #[cfg(feature = "compress")]
+    #[cfg(feature = "__compress")]
     stream: dev::Decompress<dev::Payload>,
-    #[cfg(not(feature = "compress"))]
+    #[cfg(not(feature = "__compress"))]
     stream: dev::Payload,
     buf: BytesMut,
     err: Option<PayloadError>,
@@ -309,10 +310,15 @@ impl HttpMessageBody {
             }
         }
 
-        #[cfg(feature = "compress")]
-        let stream = dev::Decompress::from_headers(payload.take(), req.headers());
-        #[cfg(not(feature = "compress"))]
-        let stream = payload.take();
+        let stream = {
+            cfg_if::cfg_if! {
+                if #[cfg(feature = "__compress")] {
+                    dev::Decompress::from_headers(payload.take(), req.headers())
+                } else {
+                    payload.take()
+                }
+            }
+        };
 
         HttpMessageBody {
             stream,
@@ -390,6 +396,8 @@ mod tests {
         assert!(cfg.check_mimetype(&req).is_ok());
     }
 
+    // allow deprecated App::data
+    #[allow(deprecated)]
     #[actix_rt::test]
     async fn test_config_recall_locations() {
         async fn bytes_handler(_: Bytes) -> impl Responder {
diff --git a/src/types/query.rs b/src/types/query.rs
index 698c4d02f..ca300139a 100644
--- a/src/types/query.rs
+++ b/src/types/query.rs
@@ -118,8 +118,7 @@ where
     fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future {
         let error_handler = req
             .app_data::<QueryConfig>()
-            .map(|c| c.err_handler.clone())
-            .unwrap_or(None);
+            .and_then(|c| c.err_handler.clone());
 
         serde_urlencoded::from_str::<T>(req.query_string())
             .map(|val| ok(Query(val)))
@@ -266,7 +265,7 @@ mod tests {
         let req = TestRequest::with_uri("/name/user1/")
             .app_data(QueryConfig::default().error_handler(|e, _| {
                 let resp = HttpResponse::UnprocessableEntity().finish();
-                InternalError::from_response(e, resp.into()).into()
+                InternalError::from_response(e, resp).into()
             }))
             .to_srv_request();
 
diff --git a/src/web.rs b/src/web.rs
index 8662848a4..40ac46275 100644
--- a/src/web.rs
+++ b/src/web.rs
@@ -43,7 +43,6 @@ pub use crate::types::*;
 /// the exposed `Params` object:
 ///
 /// ```
-/// # extern crate actix_web;
 /// use actix_web::{web, App, HttpResponse};
 ///
 /// let app = App::new().service(
diff --git a/tests/test_error_propagation.rs b/tests/test_error_propagation.rs
new file mode 100644
index 000000000..3e7320920
--- /dev/null
+++ b/tests/test_error_propagation.rs
@@ -0,0 +1,99 @@
+use std::sync::Arc;
+
+use actix_utils::future::{ok, Ready};
+use actix_web::{
+    dev::{forward_ready, Service, ServiceRequest, ServiceResponse, Transform},
+    get,
+    test::{call_service, init_service, TestRequest},
+    ResponseError,
+};
+use futures_core::future::LocalBoxFuture;
+use futures_util::lock::Mutex;
+
+#[derive(Debug, Clone)]
+pub struct MyError;
+
+impl ResponseError for MyError {}
+
+impl std::fmt::Display for MyError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "A custom error")
+    }
+}
+
+#[get("/test")]
+async fn test() -> Result<actix_web::HttpResponse, actix_web::error::Error> {
+    return Err(MyError.into());
+}
+
+#[derive(Clone)]
+pub struct SpyMiddleware(Arc<Mutex<Option<bool>>>);
+
+impl<S, B> Transform<S, ServiceRequest> for SpyMiddleware
+where
+    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = actix_web::Error>,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Response = ServiceResponse<B>;
+    type Error = actix_web::Error;
+    type Transform = Middleware<S>;
+    type InitError = ();
+    type Future = Ready<Result<Self::Transform, Self::InitError>>;
+
+    fn new_transform(&self, service: S) -> Self::Future {
+        ok(Middleware {
+            was_error: self.0.clone(),
+            service,
+        })
+    }
+}
+
+#[doc(hidden)]
+pub struct Middleware<S> {
+    was_error: Arc<Mutex<Option<bool>>>,
+    service: S,
+}
+
+impl<S, B> Service<ServiceRequest> for Middleware<S>
+where
+    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = actix_web::Error>,
+    S::Future: 'static,
+    B: 'static,
+{
+    type Response = ServiceResponse<B>;
+    type Error = actix_web::Error;
+    type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+    forward_ready!(service);
+
+    fn call(&self, req: ServiceRequest) -> Self::Future {
+        let lock = self.was_error.clone();
+        let response_future = self.service.call(req);
+        Box::pin(async move {
+            let response = response_future.await;
+            if let Ok(success) = &response {
+                *lock.lock().await = Some(success.response().error().is_some());
+            }
+            response
+        })
+    }
+}
+
+#[actix_rt::test]
+async fn error_cause_should_be_propagated_to_middlewares() {
+    let lock = Arc::new(Mutex::new(None));
+    let spy_middleware = SpyMiddleware(lock.clone());
+
+    let app = init_service(
+        actix_web::App::new()
+            .wrap(spy_middleware.clone())
+            .service(test),
+    )
+    .await;
+
+    call_service(&app, TestRequest::with_uri("/test").to_request()).await;
+
+    let was_error_captured = lock.lock().await.unwrap();
+    assert!(was_error_captured);
+}
diff --git a/tests/test_server.rs b/tests/test_server.rs
index c341aa0ce..afea39dd9 100644
--- a/tests/test_server.rs
+++ b/tests/test_server.rs
@@ -29,6 +29,7 @@ use openssl::{
     x509::X509,
 };
 use rand::{distributions::Alphanumeric, Rng};
+use zstd::stream::{read::Decoder as ZstdDecoder, write::Encoder as ZstdEncoder};
 
 use actix_web::dev::BodyEncoding;
 use actix_web::middleware::{Compress, NormalizePath, TrailingSlash};
@@ -476,6 +477,125 @@ async fn test_body_brotli() {
     assert_eq!(Bytes::from(dec), Bytes::from_static(STR.as_ref()));
 }
 
+#[actix_rt::test]
+async fn test_body_zstd() {
+    let srv = actix_test::start_with(actix_test::config().h1(), || {
+        App::new()
+            .wrap(Compress::new(ContentEncoding::Zstd))
+            .service(web::resource("/").route(web::to(move || HttpResponse::Ok().body(STR))))
+    });
+
+    // client request
+    let mut response = srv
+        .get("/")
+        .append_header((ACCEPT_ENCODING, "zstd"))
+        .no_decompress()
+        .send()
+        .await
+        .unwrap();
+    assert!(response.status().is_success());
+
+    // read response
+    let bytes = response.body().await.unwrap();
+
+    // decode
+    let mut e = ZstdDecoder::new(&bytes[..]).unwrap();
+    let mut dec = Vec::new();
+    e.read_to_end(&mut dec).unwrap();
+    assert_eq!(Bytes::from(dec), Bytes::from_static(STR.as_ref()));
+}
+
+#[actix_rt::test]
+async fn test_body_zstd_streaming() {
+    let srv = actix_test::start_with(actix_test::config().h1(), || {
+        App::new()
+            .wrap(Compress::new(ContentEncoding::Zstd))
+            .service(web::resource("/").route(web::to(move || {
+                HttpResponse::Ok()
+                    .streaming(TestBody::new(Bytes::from_static(STR.as_ref()), 24))
+            })))
+    });
+
+    // client request
+    let mut response = srv
+        .get("/")
+        .append_header((ACCEPT_ENCODING, "zstd"))
+        .no_decompress()
+        .send()
+        .await
+        .unwrap();
+    assert!(response.status().is_success());
+
+    // read response
+    let bytes = response.body().await.unwrap();
+
+    // decode
+    let mut e = ZstdDecoder::new(&bytes[..]).unwrap();
+    let mut dec = Vec::new();
+    e.read_to_end(&mut dec).unwrap();
+    assert_eq!(Bytes::from(dec), Bytes::from_static(STR.as_ref()));
+}
+
+#[actix_rt::test]
+async fn test_zstd_encoding() {
+    let srv = actix_test::start_with(actix_test::config().h1(), || {
+        App::new().service(
+            web::resource("/").route(web::to(move |body: Bytes| HttpResponse::Ok().body(body))),
+        )
+    });
+
+    let mut e = ZstdEncoder::new(Vec::new(), 5).unwrap();
+    e.write_all(STR.as_ref()).unwrap();
+    let enc = e.finish().unwrap();
+
+    // client request
+    let request = srv
+        .post("/")
+        .append_header((CONTENT_ENCODING, "zstd"))
+        .send_body(enc.clone());
+    let mut response = request.await.unwrap();
+    assert!(response.status().is_success());
+
+    // read response
+    let bytes = response.body().await.unwrap();
+    assert_eq!(bytes, Bytes::from_static(STR.as_ref()));
+}
+
+#[actix_rt::test]
+async fn test_zstd_encoding_large() {
+    let data = rand::thread_rng()
+        .sample_iter(&Alphanumeric)
+        .take(320_000)
+        .map(char::from)
+        .collect::<String>();
+
+    let srv = actix_test::start_with(actix_test::config().h1(), || {
+        App::new().service(
+            web::resource("/")
+                .app_data(web::PayloadConfig::new(320_000))
+                .route(web::to(move |body: Bytes| {
+                    HttpResponse::Ok().streaming(TestBody::new(body, 10240))
+                })),
+        )
+    });
+
+    let mut e = ZstdEncoder::new(Vec::new(), 5).unwrap();
+    e.write_all(data.as_ref()).unwrap();
+    let enc = e.finish().unwrap();
+
+    // client request
+    let request = srv
+        .post("/")
+        .append_header((CONTENT_ENCODING, "zstd"))
+        .send_body(enc.clone());
+    let mut response = request.await.unwrap();
+    assert!(response.status().is_success());
+
+    // read response
+    let bytes = response.body().limit(320_000).await.unwrap();
+    assert_eq!(bytes, Bytes::from(data));
+}
+
 #[actix_rt::test]
 async fn test_encoding() {
     let srv = actix_test::start_with(actix_test::config().h1(), || {
@@ -759,7 +879,7 @@ async fn test_brotli_encoding_large_openssl() {
     assert_eq!(bytes, Bytes::from(data));
 }
 
-#[cfg(all(feature = "rustls", feature = "openssl"))]
+#[cfg(feature = "rustls")]
 mod plus_rustls {
     use std::io::BufReader;
 
@@ -908,6 +1028,8 @@ async fn test_normalize() {
     assert!(response.status().is_success());
 }
 
+// allow deprecated App::data
+#[allow(deprecated)]
 #[actix_rt::test]
 async fn test_data_drop() {
     use std::sync::{