axum: factor out non-generic parts of request conversion

This saves ~10% in binary size!

src/api/ruma_wrapper/axum.rs

@@ -15,12 +15,13 @@ use axum_extra::{
     typed_header::TypedHeaderRejectionReason,
     TypedHeader,
 };
-use bytes::{BufMut, BytesMut};
+use bytes::{BufMut, Bytes, BytesMut};
 use http::{Request, StatusCode};
 use http_body_util::BodyExt;
 use ruma::{
     api::{
-        client::error::ErrorKind, AuthScheme, IncomingRequest, OutgoingResponse,
+        client::error::ErrorKind, AuthScheme, IncomingRequest, Metadata,
+        OutgoingResponse,
     },
     CanonicalJsonValue, OwnedDeviceId, OwnedServerName, OwnedUserId, UserId,
 };
@@ -37,18 +38,24 @@ enum Token {
     None,
 }
 
-#[async_trait]
-impl<T, S> FromRequest<S> for Ar<T>
-where
-    T: IncomingRequest,
-{
-    type Rejection = Error;
+/// Return value of [`ar_from_request_inner()`], used to construct an [`Ar`].
+struct ArPieces {
+    sender_user: Option<OwnedUserId>,
+    sender_device: Option<OwnedDeviceId>,
+    sender_servername: Option<OwnedServerName>,
+    json_body: Option<CanonicalJsonValue>,
+    appservice_info: Option<RegistrationInfo>,
+    path_params: Path<Vec<String>>,
+    http_request: Request<Bytes>,
+}
 
-    #[allow(clippy::too_many_lines)]
-    async fn from_request(
+/// Non-generic part of [`Ar::from_request()`]. Splitting this out reduces
+/// binary size by ~10%.
+#[allow(clippy::too_many_lines)]
+async fn ar_from_request_inner(
     req: axum::extract::Request,
-        _state: &S,
-    ) -> Result<Self, Self::Rejection> {
+    metadata: Metadata,
+) -> Result<ArPieces> {
     #[derive(Deserialize)]
     struct QueryParams {
         access_token: Option<String>,
@@ -68,7 +75,6 @@ where
         (parts, body)
     };
 
-        let metadata = T::METADATA;
     let auth_header: Option<TypedHeader<Authorization<Bearer>>> =
         parts.extract().await?;
     let path_params: Path<Vec<String>> = parts.extract().await?;
@@ -177,10 +183,7 @@ where
                     .extract::<TypedHeader<Authorization<XMatrix>>>()
                     .await
                     .map_err(|e| {
-                            warn!(
-                                "Missing or invalid Authorization header: {}",
-                                e
-                            );
+                        warn!("Missing or invalid Authorization header: {}", e);
 
                         let msg = match e.reason() {
                             TypedHeaderRejectionReason::Missing => {
@@ -208,9 +211,7 @@ where
                 let mut request_map = BTreeMap::from_iter([
                     (
                         "method".to_owned(),
-                            CanonicalJsonValue::String(
-                                parts.method.to_string(),
-                            ),
+                        CanonicalJsonValue::String(parts.method.to_string()),
                     ),
                     (
                         "uri".to_owned(),
@@ -239,8 +240,7 @@ where
                 ]);
 
                 if let Some(json_body) = &json_body {
-                        request_map
-                            .insert("content".to_owned(), json_body.clone());
+                    request_map.insert("content".to_owned(), json_body.clone());
                 };
 
                 let keys_result = services()
@@ -268,24 +268,20 @@ where
                     keys,
                 )]);
 
-                    match ruma::signatures::verify_json(
-                        &pub_key_map,
-                        &request_map,
-                    ) {
+                match ruma::signatures::verify_json(&pub_key_map, &request_map)
+                {
                     Ok(()) => (None, None, Some(x_matrix.origin), None),
                     Err(e) => {
                         warn!(
-                                "Failed to verify json request from {}: \
-                                 {}\n{:?}",
+                            "Failed to verify json request from {}: {}\n{:?}",
                             x_matrix.origin, e, request_map
                         );
 
                         if parts.uri.to_string().contains('@') {
                             warn!(
-                                    "Request uri contained '@' character. \
-                                     Make sure your reverse proxy gives \
-                                     Grapevine the raw uri (apache: use \
-                                     nocanon)"
+                                "Request uri contained '@' character. Make \
+                                 sure your reverse proxy gives Grapevine the \
+                                 raw uri (apache: use nocanon)"
                             );
                         }
 
@@ -308,8 +304,7 @@ where
             ) => {
                 return Err(Error::BadRequest(
                     ErrorKind::Unauthorized,
-                        "Only server signatures should be used on this \
-                         endpoint.",
+                    "Only server signatures should be used on this endpoint.",
                 ));
             }
             (AuthScheme::AppserviceToken, Token::User(_)) => {
@@ -327,10 +322,7 @@ where
 
     if let Some(CanonicalJsonValue::Object(json_body)) = &mut json_body {
         let user_id = sender_user.clone().unwrap_or_else(|| {
-                UserId::parse_with_server_name(
-                    "",
-                    services().globals.server_name(),
-                )
+            UserId::parse_with_server_name("", services().globals.server_name())
                 .expect("we know this is valid")
         });
 
@@ -347,8 +339,7 @@ where
                 )
             });
 
-            if let Some(CanonicalJsonValue::Object(initial_request)) =
-                uiaa_request
+        if let Some(CanonicalJsonValue::Object(initial_request)) = uiaa_request
         {
             for (key, value) in initial_request {
                 json_body.entry(key).or_insert(value);
@@ -360,15 +351,39 @@ where
             .expect("value serialization can't fail");
         body = buf.into_inner().freeze();
     }
-
-        let http_request = http_request.body(&*body).unwrap();
+    let http_request = http_request.body(body).unwrap();
 
     debug!("{:?}", http_request);
 
-        let body = T::try_from_http_request(http_request, &path_params)
+    Ok(ArPieces {
+        sender_user,
+        sender_device,
+        sender_servername,
+        json_body,
+        appservice_info,
+        path_params,
+        http_request,
+    })
+}
+
+#[async_trait]
+impl<T, S> FromRequest<S> for Ar<T>
+where
+    T: IncomingRequest,
+{
+    type Rejection = Error;
+
+    async fn from_request(
+        req: axum::extract::Request,
+        _state: &S,
+    ) -> Result<Self, Self::Rejection> {
+        let pieces = ar_from_request_inner(req, T::METADATA).await?;
+
+        let body =
+            T::try_from_http_request(pieces.http_request, &pieces.path_params)
                 .map_err(|e| {
                     warn!("try_from_http_request failed: {:?}", e);
-                debug!("JSON body: {:?}", json_body);
+                    debug!("JSON body: {:?}", pieces.json_body);
                     Error::BadRequest(
                         ErrorKind::BadJson,
                         "Failed to deserialize request.",
@@ -377,11 +392,11 @@ where
 
         Ok(Ar {
             body,
-            sender_user,
-            sender_device,
-            sender_servername,
-            json_body,
-            appservice_info,
+            sender_user: pieces.sender_user,
+            sender_device: pieces.sender_device,
+            sender_servername: pieces.sender_servername,
+            json_body: pieces.json_body,
+            appservice_info: pieces.appservice_info,
         })
     }
 }