Remove AddExtensionLayer (#807)

* Remove `AddExtensionLayer`

Its deprecated on 0.4.x so we can remove it from `main`.

* changelog

axum/CHANGELOG.md

@@ -56,6 +56,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
         - `MatchedPathRejection`
         - `WebSocketUpgradeRejection`
 - **breaking:** `Redirect::found` has been removed ([#800])
+- **breaking:** `AddExtensionLayer` has been removed. Use `Extension` instead. It now implements
+  `tower::Layer` ([#807])
 - **fixed:** Set `Allow` header when responding with `405 Method Not Allowed` ([#733])
 - **fixed:** Correctly set the `Content-Length` header for response to `HEAD`
   requests ([#734])
@@ -76,6 +78,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [#797]: https://github.com/tokio-rs/axum/pull/797
 [#800]: https://github.com/tokio-rs/axum/pull/800
 [#801]: https://github.com/tokio-rs/axum/pull/801
+[#807]: https://github.com/tokio-rs/axum/pull/807
 
 # 0.4.4 (13. January, 2022)
 

axum/src/add_extension.rs

@@ -2,41 +2,8 @@
 
 use http::Request;
 use std::task::{Context, Poll};
-use tower_layer::Layer;
 use tower_service::Service;
 
-/// [`Layer`] for adding some shareable value to [request extensions].
-///
-/// See [Sharing state with handlers](index.html#sharing-state-with-handlers)
-/// for more details.
-///
-/// [request extensions]: https://docs.rs/http/latest/http/struct.Extensions.html
-#[derive(Clone, Copy, Debug)]
-pub struct AddExtensionLayer<T> {
-    value: T,
-}
-
-impl<T> AddExtensionLayer<T> {
-    /// Create a new [`AddExtensionLayer`].
-    pub fn new(value: T) -> Self {
-        Self { value }
-    }
-}
-
-impl<S, T> Layer<S> for AddExtensionLayer<T>
-where
-    T: Clone,
-{
-    type Service = AddExtension<S, T>;
-
-    fn layer(&self, inner: S) -> Self::Service {
-        AddExtension {
-            inner,
-            value: self.value.clone(),
-        }
-    }
-}
-
 /// Middleware for adding some shareable value to [request extensions].
 ///
 /// See [Sharing state with handlers](index.html#sharing-state-with-handlers)
@@ -49,13 +16,6 @@ pub struct AddExtension<S, T> {
     pub(crate) value: T,
 }
 
-impl<S, T> AddExtension<S, T> {
-    /// Create a new [`AddExtensionLayer`].
-    pub fn layer(value: T) -> AddExtensionLayer<T> {
-        AddExtensionLayer::new(value)
-    }
-}
-
 impl<ResBody, S, T> Service<Request<ResBody>> for AddExtension<S, T>
 where
     S: Service<Request<ResBody>>,

axum/src/docs/extract.md

@@ -376,7 +376,7 @@ use axum::{
     http::StatusCode,
     response::{IntoResponse, Response},
     routing::get,
-    AddExtensionLayer, Router,
+    Router,
 };
 
 #[derive(Clone)]
@@ -416,7 +416,7 @@ async fn handler(user: AuthenticatedUser) {
 
 let state = State { /* ... */ };
 
-let app = Router::new().route("/", get(handler)).layer(AddExtensionLayer::new(state));
+let app = Router::new().route("/", get(handler)).layer(Extension(state));
 # async {
 # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
 # };

axum/src/docs/middleware.md

@@ -23,7 +23,7 @@ once, instead of calling `layer` (or `route_layer`) repeatedly:
 ```rust
 use axum::{
     routing::get,
-    AddExtensionLayer,
+    Extension,
     Router,
 };
 use tower_http::{trace::TraceLayer};
@@ -39,7 +39,7 @@ let app = Router::new()
     .layer(
         ServiceBuilder::new()
             .layer(TraceLayer::new_for_http())
-            .layer(AddExtensionLayer::new(State {}))
+            .layer(Extension(State {}))
     );
 # async {
 # axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
@@ -74,9 +74,9 @@ use axum::{routing::get, Router};
 
 async fn handler() {}
 
-# let layer_one = axum::AddExtensionLayer::new(());
+# let layer_one = axum::Extension(());
-# let layer_two = axum::AddExtensionLayer::new(());
+# let layer_two = axum::Extension(());
-# let layer_three = axum::AddExtensionLayer::new(());
+# let layer_three = axum::Extension(());
 #
 let app = Router::new()
     .route("/", get(handler))
@@ -130,9 +130,9 @@ use axum::{routing::get, Router};
 
 async fn handler() {}
 
-# let layer_one = axum::AddExtensionLayer::new(());
+# let layer_one = axum::Extension(());
-# let layer_two = axum::AddExtensionLayer::new(());
+# let layer_two = axum::Extension(());
-# let layer_three = axum::AddExtensionLayer::new(());
+# let layer_three = axum::Extension(());
 #
 let app = Router::new()
     .route("/", get(handler))

axum/src/lib.rs

@@ -409,7 +409,7 @@ pub mod routing;
 #[cfg(test)]
 mod test_helpers;
 
-pub use add_extension::{AddExtension, AddExtensionLayer};
+pub use add_extension::AddExtension;
 #[doc(no_inline)]
 pub use async_trait::async_trait;
 #[cfg(feature = "headers")]