github tokio-rs/axum axum-v0.6.0-rc.1
axum - v0.6.0-rc.1
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latest releases: axum-v0.8.0-alpha.1, axum-extra-v0.10.0-alpha.1, axum-macros-v0.5.0-alpha.1...
pre-release2 years ago

Routing

  • breaking: Nested Routers will no longer delegate to the outer Router's
    fallback. Instead you must explicitly set a fallback on the inner Router (#1086)

    This nested router on 0.5: 

    use axum::{Router, handler::Handler};

let api_routes = Router::new();

let app = Router::new()
    .nest("/api", api_routes)
    .fallback(fallback.into_service());

async fn fallback() {}

    Becomes this in 0.6: 

    use axum::Router;

let api_routes = Router::new()
    // we have to explicitly set the fallback here
    // since nested routers no longer delegate to the outer
    // router's fallback
    .fallback(fallback);

let app = Router::new()
    .nest("/api", api_routes)
    .fallback(fallback);

async fn fallback() {}

  • breaking: The request /foo/ no longer matches /foo/*rest. If you want
    to match /foo/ you have to add a route specifically for that (#1086)

    For example: 

    use axum::{Router, routing::get, extract::Path};

let app = Router::new()
    // this will match `/foo/bar/baz`
    .route("/foo/*rest", get(handler))
    // this will match `/foo/`
    .route("/foo/", get(handler))
    // if you want `/foo` to match you must also add an explicit route for it
    .route("/foo", get(handler));

async fn handler(
    // use an `Option` because `/foo/` and `/foo` don't have any path params
    params: Option<Path<String>>,
) {}

  • breaking: Path params for wildcard routes no longer include the prefix
    /. e.g. /foo.js will match /*filepath with a value of foo.js, not
    /foo.js (#1086)

    For example: 

    use axum::{Router, routing::get, extract::Path};

let app = Router::new().route("/foo/*rest", get(handler));

async fn handler(
    Path(params): Path<String>,
) {
    // for the request `/foo/bar/baz` the value of `params` will be `bar/baz`
    //
    // on 0.5 it would be `/bar/baz`
}

  • fixed: Routes like /foo and /*rest are no longer considered
    overlapping. /foo will take priority (#1086)

    For example: 

    use axum::{Router, routing::get};

let app = Router::new()
    // this used to not be allowed but now just works
    .route("/foo/*rest", get(foo))
    .route("/foo/bar", get(bar));

async fn foo() {}

async fn bar() {}

  • breaking: Trailing slash redirects have been removed. Previously if you
    added a route for /foo, axum would redirect calls to /foo/ to /foo (or
    vice versa for /foo/). That is no longer supported and such requests will
    now be sent to the fallback. Consider using
    axum_extra::routing::RouterExt::route_with_tsr if you want the old behavior
    (#1119)

    For example: 

    use axum::{Router, routing::get};

let app = Router::new()
    // a request to `GET /foo/` will now get `404 Not Found`
    // whereas in 0.5 axum would redirect to `/foo`
    //
    // same goes the other way if you had the route `/foo/`
    // axum will no longer redirect from `/foo` to `/foo/`
    .route("/foo", get(handler));

async fn handler() {}

  • breaking: Router::fallback now only accepts Handlers (similarly to
    what get, post, etc accept). Use the new Router::fallback_service for
    setting any Service as the fallback (#1155)

    This fallback on 0.5: 

    use axum::{Router, handler::Handler};

let app = Router::new().fallback(fallback.into_service());

async fn fallback() {}

    Becomes this in 0.6 

    use axum::Router;

let app = Router::new().fallback(fallback);

async fn fallback() {}

  • breaking: Allow Error: Into<Infallible> for Route::{layer, route_layer} (#924)

  • breaking: MethodRouter now panics on overlapping routes (#1102)

  • breaking: Router::route now only accepts MethodRouters created with
    get, post, etc. Use the new Router::route_service for routing to
    any Services (#1155)

Extractors

  • added: Added new type safe State extractor. This can be used with
    Router::with_state and gives compile errors for missing states, whereas
    Extension would result in runtime errors (#1155)

    We recommend migrating from Extension to State since that is more type
    safe and faster. That is done by using Router::with_state and State.

    This setup in 0.5 

    use axum::{routing::get, Extension, Router};

let app = Router::new()
    .route("/", get(handler))
    .layer(Extension(AppState {}));

async fn handler(Extension(app_state): Extension<AppState>) {}

#[derive(Clone)]
struct AppState {}

    Becomes this in 0.6 using State: 

    use axum::{routing::get, extract::State, Router};

let app = Router::with_state(AppState {})
    .route("/", get(handler));

async fn handler(State(app_state): State<AppState>) {}

#[derive(Clone)]
struct AppState {}

    If you have multiple extensions you can use fields on AppState and implement
    FromRef: 

    use axum::{extract::{State, FromRef}, routing::get, Router};

let state = AppState {
    client: HttpClient {},
    database: Database {},
};

let app = Router::with_state(state).route("/", get(handler));

async fn handler(
    State(client): State<HttpClient>,
    State(database): State<Database>,
) {}

#[derive(Clone)]
struct AppState {
    client: HttpClient,
    database: Database,
}

#[derive(Clone)]
struct HttpClient {}

impl FromRef<AppState> for HttpClient {
    fn from_ref(state: &AppState) -> Self {
        state.client.clone()
    }
}

#[derive(Clone)]
struct Database {}

impl FromRef<AppState> for Database {
    fn from_ref(state: &AppState) -> Self {
        state.database.clone()
    }
}

  • breaking: It is now only possible for one extractor per handler to consume
    the request body. In 0.5 doing so would result in runtime errors but in 0.6 it
    is a compile error (#1272)

    axum enforces this by only allowing the last extractor to consume the
    request.

    For example: 

    use axum::{Json, http::HeaderMap};

// This wont compile on 0.6 because both `Json` and `String` need to consume
// the request body. You can use either `Json` or `String`, but not both.
async fn handler_1(
    json: Json<serde_json::Value>,
    string: String,
) {}

// This won't work either since `Json` is not the last extractor.
async fn handler_2(
    json: Json<serde_json::Value>,
    headers: HeaderMap,
) {}

// This works!
async fn handler_3(
    headers: HeaderMap,
    json: Json<serde_json::Value>,
) {}

    This is done by reworking the FromRequest trait and introducing a new
    FromRequestParts trait.

    If your extractor needs to consume the request body then you should implement
    FromRequest, otherwise implement FromRequestParts.

    This extractor in 0.5: 

    struct MyExtractor { /* ... */ }

#[async_trait]
impl<B> FromRequest<B> for MyExtractor
where
    B: Send,
{
    type Rejection = StatusCode;

    async fn from_request(req: &mut RequestParts<B>) -> Result<Self, Self::Rejection> {
        // ...
    }
}

    Becomes this in 0.6: 

    use axum::{
    extract::{FromRequest, FromRequestParts},
    http::{StatusCode, Request, request::Parts},
    async_trait,
};

struct MyExtractor { /* ... */ }

// implement `FromRequestParts` if you don't need to consume the request body
#[async_trait]
impl<S> FromRequestParts<S> for MyExtractor
where
    S: Send + Sync,
{
    type Rejection = StatusCode;

    async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
        // ...
    }
}

// implement `FromRequest` if you do need to consume the request body
#[async_trait]
impl<S, B> FromRequest<S, B> for MyExtractor
where
    S: Send + Sync,
    B: Send + 'static,
{
    type Rejection = StatusCode;

    async fn from_request(req: Request<B>, state: &S) -> Result<Self, Self::Rejection> {
        // ...
    }
}

  • breaking: RequestParts has been removed as part of the FromRequest
    rework (#1272)

  • breaking: BodyAlreadyExtracted has been removed (#1272)

  • breaking: The following types or traits have a new S type param
    which represents the state (#1155):

    • Router, defaults to ()
    • MethodRouter, defaults to ()
    • FromRequest, no default
    • Handler, no default

  • added: Add RequestExt and RequestPartsExt which adds convenience
    methods for running extractors to http::Request and http::request::Parts (#1301)

Middleware

  • breaking: Remove extractor_middleware which was previously deprecated.
    Use axum::middleware::from_extractor instead (#1077)
  • added: Support running extractors on middleware::from_fn functions (#1088)
  • added: Support any middleware response that implements IntoResponse (#1152)
  • breaking: Require middleware added with Handler::layer to have
    Infallible as the error type (#1152)

Misc

  • changed: axum's MSRV is now 1.60 (#1239)
  • changed: For methods that accept some S: Service, the bounds have been
    relaxed so the response type must implement IntoResponse rather than being a
    literal Response
  • fixed: Annotate panicking functions with #[track_caller] so the error
    message points to where the user added the invalid route, rather than
    somewhere internally in axum (#1248)
  • added: Add ServiceExt with methods for turning any Service into a
    MakeService similarly to Router::into_make_service (#1302)
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