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]>

examples/error-handling-and-dependency-injection/src/main.rs

@@ -9,7 +9,7 @@
 
 use axum::{
     async_trait,
-    extract::{Extension, Path},
+    extract::{Path, State},
     http::StatusCode,
     response::{IntoResponse, Response},
     routing::{get, post},
@@ -36,12 +36,9 @@ async fn main() {
     let user_repo = Arc::new(ExampleUserRepo) as DynUserRepo;
 
     // Build our application with some routes
-    let app = Router::new()
+    let app = Router::with_state(user_repo)
         .route("/users/:id", get(users_show))
-        .route("/users", post(users_create))
-        // Add our `user_repo` to all request's extensions so handlers can access
-        // it.
-        .layer(Extension(user_repo));
+        .route("/users", post(users_create));
 
     // Run our application
     let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
@@ -59,7 +56,7 @@ async fn main() {
 /// so it can be returned from handlers directly.
 async fn users_show(
     Path(user_id): Path<Uuid>,
-    Extension(user_repo): Extension<DynUserRepo>,
+    State(user_repo): State<DynUserRepo>,
 ) -> Result<Json<User>, AppError> {
     let user = user_repo.find(user_id).await?;
 
@@ -69,7 +66,7 @@ async fn users_show(
 /// Handler for `POST /users`.
 async fn users_create(
     Json(params): Json<CreateUser>,
-    Extension(user_repo): Extension<DynUserRepo>,
+    State(user_repo): State<DynUserRepo>,
 ) -> Result<Json<User>, AppError> {
     let user = user_repo.create(params).await?;