refactor: remove Option from RequestHeadType::Rc extra headers

Replace `RequestHeadType::Rc(Rc<RequestHead>, Option<HeaderMap>)` with
`RequestHeadType::Rc(Rc<RequestHead>, HeaderMap)`, using an empty
HeaderMap as the default instead of None.

This enables:
- `RequestHeadType::extra_headers_mut()` for modifying headers on both
  Owned and Rc variants
- `ConnectRequest::headers_mut()` for middleware to insert headers
  without destructuring the request

Closes #2477

actix-http/CHANGES.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Remove `Option` wrapper from `RequestHeadType::Rc` extra headers; add `RequestHeadType::extra_headers_mut()` method.
 - 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

@@ -648,7 +648,7 @@ mod tests {
         );
         extra_headers.insert(DATE, HeaderValue::from_static("date"));
 
-        let mut head = RequestHeadType::Rc(Rc::new(head), Some(extra_headers));
+        let mut head = RequestHeadType::Rc(Rc::new(head), extra_headers);
 
         let _ = head.encode_headers(
             &mut bytes,

actix-http/src/requests/head.rs

@@ -150,14 +150,32 @@ impl RequestHead {
 #[derive(Debug)]
 pub enum RequestHeadType {
     Owned(RequestHead),
-    Rc(Rc<RequestHead>, Option<HeaderMap>),
+    Rc(Rc<RequestHead>, HeaderMap),
 }
 
 impl RequestHeadType {
     pub fn extra_headers(&self) -> Option<&HeaderMap> {
         match self {
             RequestHeadType::Owned(_) => None,
-            RequestHeadType::Rc(_, headers) => headers.as_ref(),
+            RequestHeadType::Rc(_, headers) => {
+                if headers.is_empty() {
+                    None
+                } else {
+                    Some(headers)
+                }
+            }
+        }
+    }
+
+    /// Returns a mutable reference to the headers that can be modified on this request.
+    ///
+    /// For `Owned` variants, this returns the main header map.
+    /// For `Rc` variants, this returns the extra headers map (which overrides base headers
+    /// during encoding).
+    pub fn extra_headers_mut(&mut self) -> &mut HeaderMap {
+        match self {
+            RequestHeadType::Owned(head) => &mut head.headers,
+            RequestHeadType::Rc(_, headers) => headers,
         }
     }
 }

awc/CHANGES.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Add `ConnectRequest::headers_mut()` to allow middleware to modify request headers.
 - 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/client/h1proto.rs

@@ -9,7 +9,7 @@ use actix_http::{
     body::{BodySize, MessageBody},
     error::PayloadError,
     h1,
-    header::{HeaderMap, TryIntoHeaderValue, EXPECT, HOST},
+    header::{TryIntoHeaderValue, EXPECT, HOST},
     Payload, RequestHeadType, ResponseHead, StatusCode,
 };
 use actix_utils::future::poll_fn;
@@ -76,15 +76,9 @@ where
             };
 
             match wrt.get_mut().split().freeze().try_into_value() {
-                Ok(value) => match head {
-                    RequestHeadType::Owned(ref mut head) => {
-                        head.headers.insert(HOST, value);
+                Ok(value) => {
+                    head.extra_headers_mut().insert(HOST, value);
                 }
-                    RequestHeadType::Rc(_, ref mut extra_headers) => {
-                        let headers = extra_headers.get_or_insert(HeaderMap::new());
-                        headers.insert(HOST, value);
-                    }
-                },
                 Err(err) => log::error!("Can not set HOST header {err}"),
             }
         }

awc/src/client/h2proto.rs

@@ -77,10 +77,9 @@ where
     // Extracting extra headers from RequestHeadType. HeaderMap::new() does not allocate.
     let (head, extra_headers) = match head {
         RequestHeadType::Owned(head) => (RequestHeadType::Owned(head), HeaderMap::new()),
-        RequestHeadType::Rc(head, extra_headers) => (
-            RequestHeadType::Rc(head, None),
-            extra_headers.unwrap_or_else(HeaderMap::new),
-        ),
+        RequestHeadType::Rc(head, extra_headers) => {
+            (RequestHeadType::Rc(head, HeaderMap::new()), extra_headers)
+        }
     };
 
     // merging headers from head and extra headers.

awc/src/connect.rs

@@ -41,6 +41,19 @@ pub enum ConnectRequest {
     Tunnel(RequestHead, Option<net::SocketAddr>),
 }
 
+impl ConnectRequest {
+    /// Returns a mutable reference to the request headers.
+    ///
+    /// For `Client` requests using the `Rc` variant, this returns the extra headers map
+    /// (which takes priority over base headers during encoding).
+    pub fn headers_mut(&mut self) -> &mut actix_http::header::HeaderMap {
+        match self {
+            ConnectRequest::Client(head, ..) => head.extra_headers_mut(),
+            ConnectRequest::Tunnel(head, ..) => &mut head.headers,
+        }
+    }
+}
+
 /// Combined HTTP response & WebSocket tunnel type returned from connection service.
 pub enum ConnectResponse {
     /// Standard HTTP response.

awc/src/frozen.rs

@@ -49,7 +49,7 @@ impl FrozenClientRequest {
     where
         B: MessageBody + 'static,
     {
-        RequestSender::Rc(Rc::clone(&self.head), None).send_body(
+        RequestSender::Rc(Rc::clone(&self.head), HeaderMap::new()).send_body(
             self.addr,
             self.response_decompress,
             self.timeout,
@@ -60,7 +60,7 @@ impl FrozenClientRequest {
 
     /// Send a json body.
     pub fn send_json<T: Serialize>(&self, value: &T) -> SendClientRequest {
-        RequestSender::Rc(Rc::clone(&self.head), None).send_json(
+        RequestSender::Rc(Rc::clone(&self.head), HeaderMap::new()).send_json(
             self.addr,
             self.response_decompress,
             self.timeout,
@@ -71,7 +71,7 @@ impl FrozenClientRequest {
 
     /// Send an urlencoded body.
     pub fn send_form<T: Serialize>(&self, value: &T) -> SendClientRequest {
-        RequestSender::Rc(Rc::clone(&self.head), None).send_form(
+        RequestSender::Rc(Rc::clone(&self.head), HeaderMap::new()).send_form(
             self.addr,
             self.response_decompress,
             self.timeout,
@@ -86,7 +86,7 @@ impl FrozenClientRequest {
         S: Stream<Item = Result<Bytes, E>> + 'static,
         E: Into<BoxError> + 'static,
     {
-        RequestSender::Rc(Rc::clone(&self.head), None).send_stream(
+        RequestSender::Rc(Rc::clone(&self.head), HeaderMap::new()).send_stream(
             self.addr,
             self.response_decompress,
             self.timeout,
@@ -97,7 +97,7 @@ impl FrozenClientRequest {
 
     /// Send an empty body.
     pub fn send(&self) -> SendClientRequest {
-        RequestSender::Rc(Rc::clone(&self.head), None).send(
+        RequestSender::Rc(Rc::clone(&self.head), HeaderMap::new()).send(
             self.addr,
             self.response_decompress,
             self.timeout,
@@ -151,7 +151,7 @@ impl FrozenSendBuilder {
             return err.into();
         }
 
-        RequestSender::Rc(self.req.head, Some(self.extra_headers)).send_body(
+        RequestSender::Rc(self.req.head, self.extra_headers).send_body(
             self.req.addr,
             self.req.response_decompress,
             self.req.timeout,
@@ -166,7 +166,7 @@ impl FrozenSendBuilder {
             return err.into();
         }
 
-        RequestSender::Rc(self.req.head, Some(self.extra_headers)).send_json(
+        RequestSender::Rc(self.req.head, self.extra_headers).send_json(
             self.req.addr,
             self.req.response_decompress,
             self.req.timeout,
@@ -181,7 +181,7 @@ impl FrozenSendBuilder {
             return err.into();
         }
 
-        RequestSender::Rc(self.req.head, Some(self.extra_headers)).send_form(
+        RequestSender::Rc(self.req.head, self.extra_headers).send_form(
             self.req.addr,
             self.req.response_decompress,
             self.req.timeout,
@@ -200,7 +200,7 @@ impl FrozenSendBuilder {
             return err.into();
         }
 
-        RequestSender::Rc(self.req.head, Some(self.extra_headers)).send_stream(
+        RequestSender::Rc(self.req.head, self.extra_headers).send_stream(
             self.req.addr,
             self.req.response_decompress,
             self.req.timeout,
@@ -215,7 +215,7 @@ impl FrozenSendBuilder {
             return err.into();
         }
 
-        RequestSender::Rc(self.req.head, Some(self.extra_headers)).send(
+        RequestSender::Rc(self.req.head, self.extra_headers).send(
             self.req.addr,
             self.req.response_decompress,
             self.req.timeout,

awc/src/sender.rs

@@ -176,7 +176,7 @@ impl From<PrepForSendingError> for SendClientRequest {
 #[derive(Debug)]
 pub(crate) enum RequestSender {
     Owned(RequestHead),
-    Rc(Rc<RequestHead>, Option<HeaderMap>),
+    Rc(Rc<RequestHead>, HeaderMap),
 }
 
 impl RequestSender {
@@ -296,14 +296,9 @@ impl RequestSender {
                 }
             }
             RequestSender::Rc(head, extra_headers) => {
-                if !head.headers.contains_key(&key)
-                    && !extra_headers.iter().any(|h| h.contains_key(&key))
-                {
+                if !head.headers.contains_key(&key) && !extra_headers.contains_key(&key) {
                     match value.try_into_value() {
-                        Ok(v) => {
-                            let h = extra_headers.get_or_insert(HeaderMap::new());
-                            h.insert(key, v)
-                        }
+                        Ok(v) => extra_headers.insert(key, v),
                         Err(err) => return Err(err.into()),
                     };
                 }