What is the difference between a route layer and a layer?

[Lydanne]

I did not find the relevant documentation.

[dayvejones]

Hey!

layer - Apply a tower::Layer to all routes in the router

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

For example:

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

// `GET /foo` with a valid token will receive `200 OK`
// `GET /foo` with a invalid token will receive `401 Unauthorized`
// `GET /not-found` with a invalid token will receive `404 Not Found`

The route "/not-found" is missing from the router. The layer will process it, but the route_layer will not.

[Lydanne]

Thanks for your reply, I understand❤️

[sumit03guha]

I am still a bit confused. What is the difference between the following two pieces of code snippet?

let auth_router = Router::new()
        .route("/signup", post(signup))
        .route("/signin", post(signin))
        .route(
            "/protected",
            get(protected).route_layer(from_fn(login_required)),
        );

and

let auth_router = Router::new()
        .route("/signup", post(signup))
        .route("/signin", post(signin))
        .route(
            "/protected",
            get(protected).layer(from_fn(login_required)),
        );

@dayvejones help here please..

[jplatte]

In the first snippet, the middleware only runs for GET /protected. In the second snippet, the middleware runs for GET /protected, but also POST /protected, PUT /protected and so on.