WIP

axum-core/src/layer.rs

@@ -0,0 +1,5 @@
+trait Layer<S> {
+    type Service;
+
+    fn layer(&self, inner: S) -> Self::Service;
+}

axum-core/src/lib.rs

@@ -48,13 +48,19 @@
 #![allow(elided_lifetimes_in_paths, clippy::type_complexity)]
 #![forbid(unsafe_code)]
 #![cfg_attr(test, allow(clippy::float_cmp))]
+#![feature(type_alias_impl_trait)]
 
 #[macro_use]
 pub(crate) mod macros;
 
 mod error;
 mod ext_traits;
+//mod layer;
+mod service;
+
 pub use self::error::Error;
+pub use self::ext_traits::{request::RequestExt, request_parts::RequestPartsExt};
+pub use self::service::Service;
 
 pub mod body;
 pub mod extract;
@@ -62,5 +68,3 @@ pub mod response;
 
 /// Alias for a type-erased error type.
 pub type BoxError = Box<dyn std::error::Error + Send + Sync>;
-
-pub use self::ext_traits::{request::RequestExt, request_parts::RequestPartsExt};

axum-core/src/service.rs

@@ -0,0 +1,39 @@
+#![allow(missing_docs)] // temporary
+
+use http::Request;
+use std::{
+    convert::Infallible,
+    future::Future,
+    task::{Context, Poll},
+};
+use tower_service::Service as TowerService;
+
+use crate::response::{IntoResponse, Response};
+
+pub trait Service<S, ReqBody> {
+    type Future: Future<Output = Response>;
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<()>;
+    fn call(&mut self, req: Request<ReqBody>, state: &S) -> Self::Future;
+}
+
+impl<T, S, ReqBody, Resp> Service<S, ReqBody> for T
+where
+    T: TowerService<Request<ReqBody>, Response = Resp, Error = Infallible>,
+    Resp: IntoResponse,
+{
+    type Future = impl Future<Output = Response>;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<()> {
+        TowerService::poll_ready(self, cx).map(|result| result.unwrap_or_else(|e| match e {}))
+    }
+
+    fn call(&mut self, req: Request<ReqBody>, _state: &S) -> Self::Future {
+        let fut = TowerService::call(self, req);
+        async move {
+            match fut.await {
+                Ok(res) => res.into_response(),
+                Err(e) => match e {},
+            }
+        }
+    }
+}

axum/src/handler/mod.rs

@@ -145,7 +145,7 @@ pub trait Handler<T, S, B = Body>: Clone + Send + Sized + 'static {
     fn layer<L, NewReqBody>(self, layer: L) -> Layered<L, Self, T, S, B, NewReqBody>
     where
         L: Layer<HandlerService<Self, T, S, B>> + Clone,
-        L::Service: Service<Request<NewReqBody>>,
+        L::Service: crate::Service<S, NewReqBody>,
     {
         Layered {
             layer,

axum/src/lib.rs

@@ -487,7 +487,7 @@ pub use self::typed_header::TypedHeader;
 pub use self::form::Form;
 
 #[doc(inline)]
-pub use axum_core::{BoxError, Error, RequestExt, RequestPartsExt};
+pub use axum_core::{BoxError, Error, RequestExt, RequestPartsExt, Service};
 
 #[cfg(feature = "macros")]
 pub use axum_macros::debug_handler;

axum/src/middleware/from_extractor.rs

@@ -1,6 +1,7 @@
 use crate::{
     extract::FromRequestParts,
     response::{IntoResponse, Response},
+    Service,
 };
 use futures_util::{future::BoxFuture, ready};
 use http::Request;
@@ -13,7 +14,6 @@ use std::{
     task::{Context, Poll},
 };
 use tower_layer::Layer;
-use tower_service::Service;
 
 /// Create a middleware from an extractor.
 ///
@@ -90,16 +90,8 @@ use tower_service::Service;
 /// ```
 ///
 /// [`Bytes`]: bytes::Bytes
-pub fn from_extractor<E>() -> FromExtractorLayer<E, ()> {
+pub fn from_extractor<E>() -> FromExtractorLayer<E> {
-    from_extractor_with_state(())
-}
-
-/// Create a middleware from an extractor with the given state.
-///
-/// See [`State`](crate::extract::State) for more details about accessing state.
-pub fn from_extractor_with_state<E, S>(state: S) -> FromExtractorLayer<E, S> {
     FromExtractorLayer {
-        state,
         _marker: PhantomData,
     }
 }
@@ -110,45 +102,32 @@ pub fn from_extractor_with_state<E, S>(state: S) -> FromExtractorLayer<E, S> {
 /// See [`from_extractor`] for more details.
 ///
 /// [`Layer`]: tower::Layer
-pub struct FromExtractorLayer<E, S> {
+pub struct FromExtractorLayer<E> {
-    state: S,
     _marker: PhantomData<fn() -> E>,
 }
 
-impl<E, S> Clone for FromExtractorLayer<E, S>
+impl<E> Clone for FromExtractorLayer<E> {
-where
-    S: Clone,
-{
     fn clone(&self) -> Self {
         Self {
-            state: self.state.clone(),
             _marker: PhantomData,
         }
     }
 }
 
-impl<E, S> fmt::Debug for FromExtractorLayer<E, S>
+impl<E> fmt::Debug for FromExtractorLayer<E> {
-where
-    S: fmt::Debug,
-{
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("FromExtractorLayer")
-            .field("state", &self.state)
             .field("extractor", &format_args!("{}", std::any::type_name::<E>()))
             .finish()
     }
 }
 
-impl<E, T, S> Layer<T> for FromExtractorLayer<E, S>
+impl<E, T> Layer<T> for FromExtractorLayer<E> {
-where
+    type Service = FromExtractor<T, E>;
-    S: Clone,
-{
-    type Service = FromExtractor<T, E, S>;
 
     fn layer(&self, inner: T) -> Self::Service {
         FromExtractor {
             inner,
-            state: self.state.clone(),
             _extractor: PhantomData,
         }
     }
@@ -157,66 +136,58 @@ where
 /// Middleware that runs an extractor and discards the value.
 ///
 /// See [`from_extractor`] for more details.
-pub struct FromExtractor<T, E, S> {
+pub struct FromExtractor<T, E> {
     inner: T,
-    state: S,
     _extractor: PhantomData<fn() -> E>,
 }
 
 #[test]
 fn traits() {
     use crate::test_helpers::*;
-    assert_send::<FromExtractor<(), NotSendSync, ()>>();
+    assert_send::<FromExtractor<(), NotSendSync>>();
-    assert_sync::<FromExtractor<(), NotSendSync, ()>>();
+    assert_sync::<FromExtractor<(), NotSendSync>>();
 }
 
-impl<T, E, S> Clone for FromExtractor<T, E, S>
+impl<T, E> Clone for FromExtractor<T, E>
 where
     T: Clone,
-    S: Clone,
 {
     fn clone(&self) -> Self {
         Self {
             inner: self.inner.clone(),
-            state: self.state.clone(),
             _extractor: PhantomData,
         }
     }
 }
 
-impl<T, E, S> fmt::Debug for FromExtractor<T, E, S>
+impl<T, E> fmt::Debug for FromExtractor<T, E>
 where
     T: fmt::Debug,
-    S: fmt::Debug,
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("FromExtractor")
             .field("inner", &self.inner)
-            .field("state", &self.state)
             .field("extractor", &format_args!("{}", std::any::type_name::<E>()))
             .finish()
     }
 }
 
-impl<T, E, B, S> Service<Request<B>> for FromExtractor<T, E, S>
+impl<T, E, B, S> Service<S, B> for FromExtractor<T, E>
 where
     E: FromRequestParts<S> + 'static,
     B: Send + 'static,
-    T: Service<Request<B>> + Clone,
+    T: Service<S, B> + Clone,
-    T::Response: IntoResponse,
     S: Clone + Send + Sync + 'static,
 {
-    type Response = Response;
-    type Error = T::Error;
     type Future = ResponseFuture<B, T, E, S>;
 
     #[inline]
-    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<()> {
         self.inner.poll_ready(cx)
     }
 
-    fn call(&mut self, req: Request<B>) -> Self::Future {
+    fn call(&mut self, req: Request<B>, st: &S) -> Self::Future {
-        let state = self.state.clone();
+        let state = st.to_owned();
         let extract_future = Box::pin(async move {
             let (mut parts, body) = req.into_parts();
             let extracted = E::from_request_parts(&mut parts, &state).await;
@@ -226,6 +197,7 @@ where
 
         ResponseFuture {
             state: State::Extracting {
+                st: st.clone(),
                 future: extract_future,
             },
             svc: Some(self.inner.clone()),
@@ -239,7 +211,7 @@ pin_project! {
     pub struct ResponseFuture<B, T, E, S>
     where
         E: FromRequestParts<S>,
-        T: Service<Request<B>>,
+        T: Service<S, B>,
     {
         #[pin]
         state: State<B, T, E, S>,
@@ -252,9 +224,10 @@ pin_project! {
     enum State<B, T, E, S>
     where
         E: FromRequestParts<S>,
-        T: Service<Request<B>>,
+        T: Service<S, B>,
     {
         Extracting {
+            st: S,
             future: BoxFuture<'static, (Request<B>, Result<E, E::Rejection>)>,
         },
         Call { #[pin] future: T::Future },
@@ -264,35 +237,32 @@ pin_project! {
 impl<B, T, E, S> Future for ResponseFuture<B, T, E, S>
 where
     E: FromRequestParts<S>,
-    T: Service<Request<B>>,
+    T: Service<S, B>,
-    T::Response: IntoResponse,
 {
-    type Output = Result<Response, T::Error>;
+    type Output = Response;
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         loop {
             let mut this = self.as_mut().project();
 
             let new_state = match this.state.as_mut().project() {
-                StateProj::Extracting { future } => {
+                StateProj::Extracting { future, st } => {
                     let (req, extracted) = ready!(future.as_mut().poll(cx));
 
                     match extracted {
                         Ok(_) => {
                             let mut svc = this.svc.take().expect("future polled after completion");
-                            let future = svc.call(req);
+                            let future = svc.call(req, st);
                             State::Call { future }
                         }
                         Err(err) => {
                             let res = err.into_response();
-                            return Poll::Ready(Ok(res));
+                            return Poll::Ready(res);
                         }
                     }
                 }
                 StateProj::Call { future } => {
-                    return future
+                    return future.poll(cx);
-                        .poll(cx)
-                        .map(|result| result.map(IntoResponse::into_response));
                 }
             };
 
@@ -346,10 +316,7 @@ mod tests {
         async fn handler() {}
 
         let state = Secret("secret");
-        let app = Router::new().route(
+        let app = Router::new().route("/", get(handler.layer(from_extractor())));
-            "/",
-            get(handler.layer(from_extractor_with_state::<RequireAuth, _>(state))),
-        );
 
         let client = TestClient::new(app);
 

axum/src/middleware/mod.rs

@@ -7,9 +7,7 @@ mod from_fn;
 mod map_request;
 mod map_response;
 
-pub use self::from_extractor::{
+pub use self::from_extractor::{from_extractor, FromExtractor, FromExtractorLayer};
-    from_extractor, from_extractor_with_state, FromExtractor, FromExtractorLayer,
-};
 pub use self::from_fn::{from_fn, from_fn_with_state, FromFn, FromFnLayer, Next};
 pub use self::map_request::{
     map_request, map_request_with_state, IntoMapRequestResult, MapRequest, MapRequestLayer,

axum/src/routing/method_routing.rs

@@ -919,10 +919,8 @@ where
     pub fn layer<L, NewReqBody, NewError>(self, layer: L) -> MethodRouter<S, NewReqBody, NewError>
     where
         L: Layer<Route<B, E>> + Clone + Send + 'static,
-        L::Service: Service<Request<NewReqBody>> + Clone + Send + 'static,
+        L::Service: crate::Service<S, NewReqBody> + Clone + Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Response: IntoResponse + 'static,
+        <L::Service as crate::Service<S, NewReqBody>>::Future: Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Error: Into<NewError> + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Future: Send + 'static,
         E: 'static,
         S: 'static,
         NewReqBody: HttpBody + 'static,

axum/src/routing/mod.rs

@@ -314,10 +314,8 @@ where
     pub fn layer<L, NewReqBody>(self, layer: L) -> Router<S, NewReqBody>
     where
         L: Layer<Route<B>> + Clone + Send + 'static,
-        L::Service: Service<Request<NewReqBody>> + Clone + Send + 'static,
+        L::Service: crate::Service<S, NewReqBody> + Clone + Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Response: IntoResponse + 'static,
+        <L::Service as crate::Service<S, NewReqBody>>::Future: Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Error: Into<Infallible> + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Future: Send + 'static,
         NewReqBody: HttpBody + 'static,
     {
         let routes = self
@@ -688,10 +686,8 @@ where
     fn layer<L, NewReqBody>(self, layer: L) -> Endpoint<S, NewReqBody>
     where
         L: Layer<Route<B>> + Clone + Send + 'static,
-        L::Service: Service<Request<NewReqBody>> + Clone + Send + 'static,
+        L::Service: crate::Service<S, NewReqBody> + Clone + Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Response: IntoResponse + 'static,
+        <L::Service as crate::Service<S, NewReqBody>>::Future: Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Error: Into<Infallible> + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Future: Send + 'static,
         NewReqBody: HttpBody + 'static,
     {
         match self {

axum/src/routing/route.rs

@@ -51,10 +51,8 @@ impl<B, E> Route<B, E> {
     pub(crate) fn layer<L, NewReqBody, NewError>(self, layer: L) -> Route<NewReqBody, NewError>
     where
         L: Layer<Route<B, E>> + Clone + Send + 'static,
-        L::Service: Service<Request<NewReqBody>> + Clone + Send + 'static,
+        L::Service: crate::Service<S, NewReqBody> + Clone + Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Response: IntoResponse + 'static,
+        <L::Service as crate::Service<S, NewReqBody>>::Future: Send + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Error: Into<NewError> + 'static,
-        <L::Service as Service<Request<NewReqBody>>>::Future: Send + 'static,
         NewReqBody: 'static,
         NewError: 'static,
     {