route_layer.md

Apply a [tower::Layer] to the router that will only run if the request matches a route.

Note that the middleware is only applied to existing routes. So you have to first add your routes (and / or fallback) and then call layer afterwards. Additional routes added after layer is called will not have the middleware added.

This works similarly to [MethodRouter::layer] except the middleware will only run if the request matches a route. This is useful for middleware that return early (such as authorization) which might otherwise convert a 405 Method Not Allowed into a 401 Unauthorized.

Example

use axum::{
    routing::get,
    Router,
};
use tower_http::auth::RequireAuthorizationLayer;

let app = Router::new().route(
    "/foo",
    get(|| async {})
        .route_layer(RequireAuthorizationLayer::bearer("password"))
);

// `GET /foo` with a valid token will receive `200 OK`
// `GET /foo` with a invalid token will receive `401 Unauthorized`
// `POST /FOO` with a invalid token will receive `405 Method Not Allowed`
# async {
# axum::Server::bind(&"".parse().unwrap()).serve(app.into_make_service()).await.unwrap();
# };