Add type safe state extractor (#1155)

* begin threading the state through

* Pass state to extractors

* make state extractor work

* make sure nesting with different states work

* impl Service for MethodRouter<()>

* Fix some of axum-macro's tests

* Implement more traits for `State`

* Update examples to use `State`

* consistent naming of request body param

* swap type params

* Default the state param to ()

* fix docs references

* Docs and handler state refactoring

* docs clean ups

* more consistent naming

* when does MethodRouter implement Service?

* add missing docs

* use `Router`'s default state type param

* changelog

* don't use default type param for FromRequest and RequestParts

probably safer for library authors so you don't accidentally forget

* fix examples

* minor docs tweaks

* clarify how to convert handlers into services

* group methods in one impl block

* make sure merged `MethodRouter`s can access state

* fix docs link

* test merge with same state type

* Document how to access state from middleware

* Port cookie extractors to use state to extract keys (#1250)

* Updates ECOSYSTEM with a new sample project (#1252)

* Avoid unhelpful compiler suggestion (#1251)

* fix docs typo

* document how library authors should access state

* Add `RequestParts::with_state`

* fix example

* apply suggestions from review

* add relevant changes to axum-extra and axum-core changelogs

* Add `route_service_with_tsr`

* fix trybuild expectations

* make sure `SpaRouter` works with routers that have state

* Change order of type params on FromRequest and RequestParts

* reverse order of `RequestParts::with_state` args to match type params

* Add `FromRef` trait (#1268)

* Add `FromRef` trait

* Remove unnecessary type params

* format

* fix docs link

* format examples

* Avoid unnecessary `MethodRouter`

* apply suggestions from review

Co-authored-by: Dani Pardo <[email protected]>
Co-authored-by: Jonas Platte <[email protected]>

axum-core/src/extract/tuple.rs

@@ -4,13 +4,14 @@ use async_trait::async_trait;
 use std::convert::Infallible;
 
 #[async_trait]
-impl<B> FromRequest<B> for ()
+impl<S, B> FromRequest<S, B> for ()
 where
     B: Send,
+    S: Send,
 {
     type Rejection = Infallible;
 
-    async fn from_request(_: &mut RequestParts<B>) -> Result<(), Self::Rejection> {
+    async fn from_request(_: &mut RequestParts<S, B>) -> Result<(), Self::Rejection> {
         Ok(())
     }
 }
@@ -21,14 +22,15 @@ macro_rules! impl_from_request {
     ( $($ty:ident),* $(,)? ) => {
         #[async_trait]
         #[allow(non_snake_case)]
-        impl<B, $($ty,)*> FromRequest<B> for ($($ty,)*)
+        impl<S, B, $($ty,)*> FromRequest<S, B> for ($($ty,)*)
         where
-            $( $ty: FromRequest<B> + Send, )*
+            $( $ty: FromRequest<S, B> + Send, )*
             B: Send,
+            S: Send,
         {
             type Rejection = Response;
 
-            async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
+            async fn from_request(req: &mut RequestParts<S, B>) -> Result<Self, Self::Rejection> {
                 $( let $ty = $ty::from_request(req).await.map_err(|err| err.into_response())?; )*
                 Ok(($($ty,)*))
             }