feat: expose Identity middleware (#3390)

.github/workflows/lint.yml

@@ -89,5 +89,5 @@ jobs:
       - name: Generate API diff
         run: |
           for f in $(find -mindepth 2 -maxdepth 2 -name Cargo.toml); do
-            cargo public-api --manifest-path "$f" diff ${{ github.event.pull_request.base.sha }}..${{ github.sha }}
+            cargo public-api --manifest-path "$f" --simplified diff ${{ github.event.pull_request.base.sha }}..${{ github.sha }}
           done

actix-web/CHANGES.md

@@ -4,6 +4,7 @@
 
 ### Added
 
+- Add `middleware::Identity` type.
 - Add `CustomizeResponder::add_cookie()` method.
 - Add `guard::GuardContext::app_data()` method.
 - Implement `From<Box<dyn ResponseError>>` for `Error`.

actix-web/src/middleware/compat.rs

@@ -38,15 +38,6 @@ pub struct Compat<T> {
     transform: T,
 }
 
-#[cfg(test)]
-impl Compat<super::Noop> {
-    pub(crate) fn noop() -> Self {
-        Self {
-            transform: super::Noop,
-        }
-    }
-}
-
 impl<T> Compat<T> {
     /// Wrap a middleware to give it broader compatibility.
     pub fn new(middleware: T) -> Self {
@@ -152,7 +143,7 @@ mod tests {
     use crate::{
         dev::ServiceRequest,
         http::StatusCode,
-        middleware::{self, Condition, Logger},
+        middleware::{self, Condition, Identity, Logger},
         test::{self, call_service, init_service, TestRequest},
         web, App, HttpResponse,
     };
@@ -225,7 +216,7 @@ mod tests {
     async fn compat_noop_is_noop() {
         let srv = test::ok_service();
 
-        let mw = Compat::noop()
+        let mw = Compat::new(Identity)
             .new_transform(srv.into_service())
             .await
             .unwrap();

actix-web/src/middleware/condition.rs

@@ -141,7 +141,7 @@ mod tests {
             header::{HeaderValue, CONTENT_TYPE},
             StatusCode,
         },
-        middleware::{self, ErrorHandlerResponse, ErrorHandlers},
+        middleware::{self, ErrorHandlerResponse, ErrorHandlers, Identity},
         test::{self, TestRequest},
         web::Bytes,
         HttpResponse,
@@ -158,7 +158,7 @@ mod tests {
 
     #[test]
     fn compat_with_builtin_middleware() {
-        let _ = Condition::new(true, middleware::Compat::noop());
+        let _ = Condition::new(true, middleware::Compat::new(Identity));
         let _ = Condition::new(true, middleware::Logger::default());
         let _ = Condition::new(true, middleware::Compress::default());
         let _ = Condition::new(true, middleware::NormalizePath::trim());

actix-web/src/middleware/identity.rs

@@ -2,35 +2,39 @@
 
 use actix_utils::future::{ready, Ready};
 
-use crate::dev::{Service, Transform};
+use crate::dev::{forward_ready, Service, Transform};
 
 /// A no-op middleware that passes through request and response untouched.
-pub(crate) struct Noop;
+#[derive(Debug, Clone, Default)]
+#[non_exhaustive]
+pub struct Identity;
 
-impl<S: Service<Req>, Req> Transform<S, Req> for Noop {
+impl<S: Service<Req>, Req> Transform<S, Req> for Identity {
     type Response = S::Response;
     type Error = S::Error;
-    type Transform = NoopService<S>;
+    type Transform = IdentityMiddleware<S>;
     type InitError = ();
     type Future = Ready<Result<Self::Transform, Self::InitError>>;
 
+    #[inline]
     fn new_transform(&self, service: S) -> Self::Future {
-        ready(Ok(NoopService { service }))
+        ready(Ok(IdentityMiddleware { service }))
     }
 }
 
 #[doc(hidden)]
-pub(crate) struct NoopService<S> {
+pub struct IdentityMiddleware<S> {
     service: S,
 }
 
-impl<S: Service<Req>, Req> Service<Req> for NoopService<S> {
+impl<S: Service<Req>, Req> Service<Req> for IdentityMiddleware<S> {
     type Response = S::Response;
     type Error = S::Error;
     type Future = S::Future;
 
-    crate::dev::forward_ready!(service);
+    forward_ready!(service);
 
+    #[inline]
     fn call(&self, req: Req) -> Self::Future {
         self.service.call(req)
     }

actix-web/src/middleware/mod.rs

@@ -218,31 +218,27 @@
 //! [lab_from_fn]: https://docs.rs/actix-web-lab/latest/actix_web_lab/middleware/fn.from_fn.html
 
 mod compat;
+#[cfg(feature = "__compress")]
+mod compress;
 mod condition;
 mod default_headers;
 mod err_handlers;
+mod identity;
 mod logger;
-#[cfg(test)]
-mod noop;
 mod normalize;
 
-#[cfg(test)]
+#[cfg(feature = "__compress")]
-pub(crate) use self::noop::Noop;
+pub use self::compress::Compress;
 pub use self::{
     compat::Compat,
     condition::Condition,
     default_headers::DefaultHeaders,
     err_handlers::{ErrorHandlerResponse, ErrorHandlers},
+    identity::Identity,
     logger::Logger,
     normalize::{NormalizePath, TrailingSlash},
 };
 
-#[cfg(feature = "__compress")]
-mod compress;
-
-#[cfg(feature = "__compress")]
-pub use self::compress::Compress;
-
 #[cfg(test)]
 mod tests {
     use super::*;