feat(awc): add HTTP proxy support via environment variables

Add support for HTTP_PROXY/HTTPS_PROXY/NO_PROXY environment variables
to the awc HTTP client, matching the behavior of reqwest and other
HTTP clients. Proxied requests use absolute-form URIs per RFC 7230
section 5.3.2.

Changes:
- actix-http: Add PROXY_REQUEST flag and absolute-form URI encoding
- awc: Add ProxyConfig, ClientBuilder::proxy()/no_proxy() methods
- awc: DefaultConnector routes connections through proxy when configured
- Proxy env vars are read by default; use no_proxy() to disable

actix-http/CHANGES.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Add `RequestHead::set_proxy_request()` / `is_proxy_request()` to support absolute-form URI encoding for HTTP proxy requests (RFC 7230 section 5.3.2).
 - When configured, gracefully close HTTP/1 connections after early responses to unread request bodies. [#3967]
 - Wake HTTP/1 payload receivers with an incomplete-payload error when the sender is dropped before EOF. [#3100]
 - Update `foldhash` dependency to `0.2`.

actix-http/src/h1/encoder.rs

@@ -305,11 +305,23 @@ impl MessageType for RequestHeadType {
     fn encode_status(&mut self, dst: &mut BytesMut) -> io::Result<()> {
         let head = self.as_ref();
         dst.reserve(256 + head.headers.len() * AVERAGE_HEADER_SIZE);
+
+        // RFC 7230 section 5.3.2: use absolute-form URI for proxy requests
+        let request_target = if head.is_proxy_request() {
+            head.uri.to_string()
+        } else {
+            head.uri
+                .path_and_query()
+                .map(|u| u.as_str())
+                .unwrap_or("/")
+                .to_owned()
+        };
+
         write!(
             helpers::MutWriter(dst),
             "{} {} {}",
             head.method,
-            head.uri.path_and_query().map(|u| u.as_str()).unwrap_or("/"),
+            request_target,
             match head.version {
                 Version::HTTP_09 => "HTTP/0.9",
                 Version::HTTP_10 => "HTTP/1.0",
@@ -664,6 +676,42 @@ mod tests {
         assert!(data.contains("date: date\r\n"));
     }
 
+    #[test]
+    fn test_proxy_request_absolute_uri() {
+        let mut bytes = BytesMut::with_capacity(2048);
+        let mut head = RequestHead::default();
+        head.uri = "http://example.com/foo?bar=1".parse().unwrap();
+        head.method = http::Method::GET;
+        head.set_proxy_request(true);
+
+        let mut head = RequestHeadType::Owned(head);
+        head.encode_status(&mut bytes).unwrap();
+
+        let data = String::from_utf8(Vec::from(bytes.split().freeze().as_ref())).unwrap();
+        assert!(
+            data.starts_with("GET http://example.com/foo?bar=1 HTTP/1.1"),
+            "Expected absolute-form URI for proxy request, got: {data}",
+        );
+    }
+
+    #[test]
+    fn test_non_proxy_request_origin_form() {
+        let mut bytes = BytesMut::with_capacity(2048);
+        let mut head = RequestHead::default();
+        head.uri = "http://example.com/foo?bar=1".parse().unwrap();
+        head.method = http::Method::GET;
+        // proxy flag is NOT set
+
+        let mut head = RequestHeadType::Owned(head);
+        head.encode_status(&mut bytes).unwrap();
+
+        let data = String::from_utf8(Vec::from(bytes.split().freeze().as_ref())).unwrap();
+        assert!(
+            data.starts_with("GET /foo?bar=1 HTTP/1.1"),
+            "Expected origin-form URI for non-proxy request, got: {data}",
+        );
+    }
+
     #[actix_rt::test]
     async fn test_no_content_length() {
         let mut bytes = BytesMut::with_capacity(2048);

actix-http/src/message.rs

@@ -23,7 +23,8 @@ bitflags! {
         const UPGRADE     = 0b0000_0100;
         const EXPECT      = 0b0000_1000;
         const NO_CHUNKING = 0b0001_0000;
-        const CAMEL_CASE  = 0b0010_0000;
+        const CAMEL_CASE      = 0b0010_0000;
+        const PROXY_REQUEST   = 0b0100_0000;
     }
 }
 

actix-http/src/requests/head.rs

@@ -144,6 +144,25 @@ impl RequestHead {
     pub(crate) fn set_expect(&mut self) {
         self.flags.insert(Flags::EXPECT);
     }
+
+    /// Returns whether this request should use absolute-form URI (for proxy requests).
+    #[inline]
+    pub fn is_proxy_request(&self) -> bool {
+        self.flags.contains(Flags::PROXY_REQUEST)
+    }
+
+    /// Sets whether this request should use absolute-form URI in the request line.
+    ///
+    /// When enabled, the full URI (including scheme and authority) is sent in the request line,
+    /// as required by HTTP/1.1 for requests to proxies (RFC 7230 section 5.3.2).
+    #[inline]
+    pub fn set_proxy_request(&mut self, val: bool) {
+        if val {
+            self.flags.insert(Flags::PROXY_REQUEST);
+        } else {
+            self.flags.remove(Flags::PROXY_REQUEST);
+        }
+    }
 }
 
 #[allow(clippy::large_enum_variant)]

awc/CHANGES.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Add HTTP proxy support via `HTTP_PROXY`/`HTTPS_PROXY`/`NO_PROXY` environment variables, read by default.
+- Add `ProxyConfig` type and `ClientBuilder::proxy()` / `ClientBuilder::no_proxy()` methods for explicit proxy configuration.
 - Add camel-case header controls to `WebsocketsRequest` via `camel_case_headers()` and `set_camel_case_headers()`. [#3953]
 - Update `hickory-resolver` dependency to `0.26.1`.
 - Update `rand` dependency to `0.10`.

awc/src/builder.rs

@@ -11,7 +11,8 @@ use base64::prelude::*;
 
 use crate::{
     client::{
-        ClientConfig, ConnectInfo, Connector, ConnectorService, TcpConnectError, TcpConnection,
+        proxy::ProxyConfig, ClientConfig, ConnectInfo, Connector, ConnectorService,
+        TcpConnectError, TcpConnection,
     },
     connect::DefaultConnector,
     error::SendRequestError,
@@ -34,6 +35,7 @@ pub struct ClientBuilder<S = (), M = ()> {
     middleware: M,
     local_address: Option<IpAddr>,
     max_redirects: u8,
+    proxy: ProxyConfig,
 }
 
 impl ClientBuilder {
@@ -63,6 +65,7 @@ impl ClientBuilder {
             middleware: (),
             local_address: None,
             max_redirects: 10,
+            proxy: ProxyConfig::from_env(),
         }
     }
 }
@@ -93,6 +96,7 @@ where
             stream_window_size: self.stream_window_size,
             conn_window_size: self.conn_window_size,
             max_redirects: self.max_redirects,
+            proxy: self.proxy,
         }
     }
 
@@ -159,6 +163,22 @@ where
         self
     }
 
+    /// Set proxy configuration.
+    ///
+    /// By default, proxy settings are read from environment variables
+    /// (`HTTP_PROXY`, `HTTPS_PROXY`, `NO_PROXY`). Use this method to override with
+    /// an explicit configuration.
+    pub fn proxy(mut self, proxy: ProxyConfig) -> Self {
+        self.proxy = proxy;
+        self
+    }
+
+    /// Disable proxy usage, ignoring environment variables.
+    pub fn no_proxy(mut self) -> Self {
+        self.proxy = ProxyConfig::default();
+        self
+    }
+
     /// Do not add fundamental default request headers.
     ///
     /// By default `Date` and `User-Agent` headers are set.
@@ -245,6 +265,7 @@ where
             connector: self.connector,
             local_address: self.local_address,
             max_redirects: self.max_redirects,
+            proxy: self.proxy,
         }
     }
 
@@ -284,7 +305,7 @@ where
             connector = connector.local_address(val);
         }
 
-        let connector = DefaultConnector::new(connector.finish());
+        let connector = DefaultConnector::new(connector.finish()).with_proxy(self.proxy);
         let connector = boxed::rc_service(self.middleware.new_transform(connector));
 
         Client(ClientConfig {

awc/src/client/mod.rs

@@ -18,11 +18,13 @@ mod error;
 mod h1proto;
 mod h2proto;
 mod pool;
+pub(crate) mod proxy;
 
 pub use self::{
     connection::{Connection, ConnectionIo},
     connector::{Connector, ConnectorService},
     error::{ConnectError, FreezeRequestError, InvalidUrl, SendRequestError},
+    proxy::ProxyConfig,
 };
 
 #[derive(Clone)]

awc/src/client/proxy.rs

@@ -0,0 +1,223 @@
+use std::env;
+
+use http::Uri;
+
+/// HTTP proxy configuration for the client connector.
+///
+/// Determines which proxy (if any) should be used for a given request URI,
+/// based on explicit configuration or environment variables (`HTTP_PROXY`,
+/// `HTTPS_PROXY`, `NO_PROXY`).
+#[derive(Clone, Debug)]
+pub struct ProxyConfig {
+    http_proxy: Option<Uri>,
+    https_proxy: Option<Uri>,
+    no_proxy: Option<NoProxy>,
+}
+
+impl ProxyConfig {
+    /// Creates a proxy configuration by reading standard environment variables.
+    ///
+    /// Reads `HTTP_PROXY` (or `http_proxy`), `HTTPS_PROXY` (or `https_proxy`),
+    /// and `NO_PROXY` (or `no_proxy`).
+    pub fn from_env() -> Self {
+        let http_proxy = env_var_uri("HTTP_PROXY").or_else(|| env_var_uri("http_proxy"));
+        let https_proxy = env_var_uri("HTTPS_PROXY").or_else(|| env_var_uri("https_proxy"));
+        let no_proxy = env::var("NO_PROXY")
+            .or_else(|_| env::var("no_proxy"))
+            .ok()
+            .map(|s| NoProxy::parse(&s));
+
+        Self {
+            http_proxy,
+            https_proxy,
+            no_proxy,
+        }
+    }
+
+    /// Creates a proxy configuration with an explicit HTTP proxy URI.
+    pub fn with_http_proxy(mut self, proxy: Uri) -> Self {
+        self.http_proxy = Some(proxy);
+        self
+    }
+
+    /// Creates a proxy configuration with an explicit HTTPS proxy URI.
+    pub fn with_https_proxy(mut self, proxy: Uri) -> Self {
+        self.https_proxy = Some(proxy);
+        self
+    }
+
+    /// Sets the no-proxy list (comma-separated hostnames/domains).
+    pub fn with_no_proxy(mut self, no_proxy: &str) -> Self {
+        self.no_proxy = Some(NoProxy::parse(no_proxy));
+        self
+    }
+
+    /// Returns the proxy URI to use for the given target URI, or `None` if no proxy applies.
+    pub fn proxy_for_uri(&self, uri: &Uri) -> Option<&Uri> {
+        if let Some(ref no_proxy) = self.no_proxy {
+            if let Some(host) = uri.host() {
+                if no_proxy.matches(host) {
+                    return None;
+                }
+            }
+        }
+
+        match uri.scheme_str() {
+            Some("https") | Some("wss") => self.https_proxy.as_ref(),
+            _ => self.http_proxy.as_ref(),
+        }
+    }
+
+    /// Returns `true` if any proxy is configured.
+    pub fn has_proxy(&self) -> bool {
+        self.http_proxy.is_some() || self.https_proxy.is_some()
+    }
+}
+
+impl Default for ProxyConfig {
+    fn default() -> Self {
+        Self {
+            http_proxy: None,
+            https_proxy: None,
+            no_proxy: None,
+        }
+    }
+}
+
+fn env_var_uri(name: &str) -> Option<Uri> {
+    env::var(name)
+        .ok()
+        .and_then(|val| {
+            if val.is_empty() {
+                return None;
+            }
+            match val.parse::<Uri>() {
+                Ok(uri) => Some(uri),
+                Err(err) => {
+                    log::warn!("Invalid proxy URI in {name}: {err}");
+                    None
+                }
+            }
+        })
+}
+
+/// Parsed representation of the `NO_PROXY` environment variable.
+#[derive(Clone, Debug)]
+struct NoProxy {
+    entries: Vec<String>,
+    match_all: bool,
+}
+
+impl NoProxy {
+    fn parse(value: &str) -> Self {
+        let trimmed = value.trim();
+        if trimmed == "*" {
+            return Self {
+                entries: Vec::new(),
+                match_all: true,
+            };
+        }
+
+        let entries = trimmed
+            .split(',')
+            .map(|s| s.trim().to_lowercase())
+            .filter(|s| !s.is_empty())
+            .collect();
+
+        Self {
+            entries,
+            match_all: false,
+        }
+    }
+
+    fn matches(&self, host: &str) -> bool {
+        if self.match_all {
+            return true;
+        }
+
+        let host = host.to_lowercase();
+
+        self.entries.iter().any(|entry| {
+            if entry.starts_with('.') {
+                // ".example.com" matches "foo.example.com" and "example.com"
+                host.ends_with(entry.as_str()) || host == entry[1..]
+            } else {
+                host == *entry || host.ends_with(&format!(".{entry}"))
+            }
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn no_proxy_wildcard() {
+        let np = NoProxy::parse("*");
+        assert!(np.matches("anything.example.com"));
+        assert!(np.matches("localhost"));
+    }
+
+    #[test]
+    fn no_proxy_exact_match() {
+        let np = NoProxy::parse("localhost, example.com");
+        assert!(np.matches("localhost"));
+        assert!(np.matches("example.com"));
+        assert!(!np.matches("other.com"));
+    }
+
+    #[test]
+    fn no_proxy_subdomain_match() {
+        let np = NoProxy::parse("example.com");
+        assert!(np.matches("example.com"));
+        assert!(np.matches("sub.example.com"));
+        assert!(!np.matches("notexample.com"));
+    }
+
+    #[test]
+    fn no_proxy_dot_prefix() {
+        let np = NoProxy::parse(".example.com");
+        assert!(np.matches("example.com"));
+        assert!(np.matches("sub.example.com"));
+        assert!(!np.matches("notexample.com"));
+    }
+
+    #[test]
+    fn no_proxy_case_insensitive() {
+        let np = NoProxy::parse("Example.COM");
+        assert!(np.matches("example.com"));
+        assert!(np.matches("EXAMPLE.COM"));
+    }
+
+    #[test]
+    fn proxy_for_uri_http() {
+        let config = ProxyConfig::default()
+            .with_http_proxy("http://proxy:8080".parse().unwrap());
+        let uri: Uri = "http://example.com/foo".parse().unwrap();
+        assert!(config.proxy_for_uri(&uri).is_some());
+    }
+
+    #[test]
+    fn proxy_for_uri_no_proxy() {
+        let config = ProxyConfig::default()
+            .with_http_proxy("http://proxy:8080".parse().unwrap())
+            .with_no_proxy("example.com");
+        let uri: Uri = "http://example.com/foo".parse().unwrap();
+        assert!(config.proxy_for_uri(&uri).is_none());
+    }
+
+    #[test]
+    fn proxy_for_uri_https() {
+        let config = ProxyConfig::default()
+            .with_https_proxy("http://proxy:8080".parse().unwrap());
+        let uri: Uri = "https://example.com/foo".parse().unwrap();
+        assert!(config.proxy_for_uri(&uri).is_some());
+    }
+
+    #[test]
+    fn no_proxy_empty_string() {
+        let np = NoProxy::parse("");
+        assert!(!np.matches("anything"));
+    }
+}

awc/src/connect.rs

@@ -13,7 +13,10 @@ use futures_core::{future::LocalBoxFuture, ready};
 
 use crate::{
     any_body::AnyBody,
-    client::{Connect as ClientConnect, ConnectError, Connection, ConnectionIo, SendRequestError},
+    client::{
+        proxy::ProxyConfig, Connect as ClientConnect, ConnectError, Connection, ConnectionIo,
+        SendRequestError,
+    },
     ClientResponse,
 };
 
@@ -82,11 +85,20 @@ impl ConnectResponse {
 
 pub struct DefaultConnector<S> {
     connector: S,
+    proxy: ProxyConfig,
 }
 
 impl<S> DefaultConnector<S> {
     pub(crate) fn new(connector: S) -> Self {
-        Self { connector }
+        Self {
+            connector,
+            proxy: ProxyConfig::default(),
+        }
+    }
+
+    pub(crate) fn with_proxy(mut self, proxy: ProxyConfig) -> Self {
+        self.proxy = proxy;
+        self
     }
 }
 
@@ -101,19 +113,33 @@ where
 
     actix_service::forward_ready!(connector);
 
-    fn call(&self, req: ConnectRequest) -> Self::Future {
-        // connect to the host
-        let fut = match req {
-            ConnectRequest::Client(ref head, .., addr) => self.connector.call(ClientConnect {
-                uri: head.as_ref().uri.clone(),
-                addr,
-            }),
-            ConnectRequest::Tunnel(ref head, addr) => self.connector.call(ClientConnect {
-                uri: head.uri.clone(),
-                addr,
-            }),
+    fn call(&self, mut req: ConnectRequest) -> Self::Future {
+        let (target_uri, addr) = match req {
+            ConnectRequest::Client(ref head, .., addr) => (head.as_ref().uri.clone(), addr),
+            ConnectRequest::Tunnel(ref head, addr) => (head.uri.clone(), addr),
         };
 
+        let connect_uri = if let Some(proxy_uri) = self.proxy.proxy_for_uri(&target_uri) {
+            // Set the proxy flag on the request head so the encoder uses absolute-form URI
+            match req {
+                ConnectRequest::Client(ref mut head, ..) => match head {
+                    RequestHeadType::Owned(ref mut h) => h.set_proxy_request(true),
+                    RequestHeadType::Rc(_, _) => {
+                        log::warn!("Cannot set proxy flag on Rc<RequestHead>; request will use origin-form URI");
+                    }
+                },
+                ConnectRequest::Tunnel(..) => {}
+            }
+            proxy_uri.clone()
+        } else {
+            target_uri
+        };
+
+        let fut = self.connector.call(ClientConnect {
+            uri: connect_uri,
+            addr,
+        });
+
         ConnectRequestFuture::Connection {
             fut,
             req: Some(req),

awc/src/lib.rs

@@ -138,7 +138,7 @@ pub mod http {
 pub use self::responses::{ClientResponse, JsonBody, MessageBody, ResponseBody};
 pub use self::{
     builder::ClientBuilder,
-    client::{Client, Connect, Connector},
+    client::{Client, Connect, Connector, ProxyConfig},
     connect::{BoxConnectorService, BoxedSocket, ConnectRequest, ConnectResponse},
     frozen::{FrozenClientRequest, FrozenSendBuilder},
     request::ClientRequest,