How to use tower_http::normalize_path in axum v0.7?

[duskmoon314]

Summary

I'm trying to upgrade my project from Axum v0.6.17 to v0.7.1 and come across the error that I need to provide type annotations. I followed the information provided by Rustc but need help finding out how to fix this.

Previously in Axum v0.6.17, which works fine

Ok(Server::bind(&(cfg.ip, cfg.port).into())
    .serve(
        NormalizePathLayer::trim_trailing_slash()
            .layer(
                Router::new()
                    .merge(data::api())
                    .merge(request_inspection::api())
                    .merge(http_method::api())
                    .layer(CorsLayer::new().allow_origin(AllowOrigin::mirror_request()))
                    .layer(TraceLayer::new_for_http()),
            )
            .into_make_service_with_connect_info::<SocketAddr>(),
    )
    .await?)

What I'm trying in Axum v0.7.1

let app = Router::new()
    .merge(data::api())
    .merge(request_inspection::api())
    .merge(http_method::api())
    .layer(CorsLayer::new().allow_origin(AllowOrigin::mirror_request()))
    .layer(TraceLayer::new_for_http());

let app = NormalizePathLayer::trim_trailing_slash().layer(app);

let listener = tokio::net::TcpListener::bind((cfg.ip, cfg.port)).await?;

Ok(axum::serve(listener, app.into_make_service()).await?)

rustc gives this error:

error[E0284]: type annotations needed
  --> httpbin-axum/src/main.rs:37:34
   |
37 |     Ok(axum::serve(listener, app.into_make_service()).await?)
   |                                  ^^^^^^^^^^^^^^^^^
   |
   = note: cannot satisfy `<_ as HttpBody>::Data == axum::body::Bytes`
   = note: required for `Router` to implement `tower_service::Service<axum::http::Request<_>>`
   = note: 1 redundant requirement hidden
   = note: required for `NormalizePath<Router>` to implement `tower_service::Service<axum::http::Request<_>>`
note: required by a bound in `axum::ServiceExt::into_make_service`
  --> /Users/duskmoon/.cargo/registry/src/rsproxy.cn-8f6827c7555bfaf8/axum-0.7.1/src/service_ext.rs:8:26
   |
8  | pub trait ServiceExt<R>: Service<R> + Sized {
   |                          ^^^^^^^^^^ required by this bound in `ServiceExt::into_make_service`
...
18 |     fn into_make_service(self) -> IntoMakeService<Self>;
   |        ----------------- required by a bound in this associated function
help: try using a fully qualified path to specify the expected types
   |
37 |     Ok(axum::serve(listener, <NormalizePath<Router> as ServiceExt<axum::http::Request<ReqBody>>>::into_make_service(app)).await?)
   |                              +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++   ~

For more information about this error, try `rustc --explain E0284`.

I cannot find the definition of ReqBody, so I cannot annotate the type. How to make this work?

axum version

0.7.1

[davidpdrsn]

You can use "fully qualified" syntax to call ServiceExt::into_make_service and specific the type parameters:

use axum::{extract::Request, Router, ServiceExt};
use tower::Layer;
use tower_http::normalize_path::NormalizePathLayer;

#[tokio::main]
async fn main() {
    let app = Router::new();

    let app = NormalizePathLayer::trim_trailing_slash().layer(app);

    let listener = tokio::net::TcpListener::bind("127.0.0.1:3000")
        .await
        .unwrap();

    axum::serve(listener, ServiceExt::<Request>::into_make_service(app)) // <-- this
        .await
        .unwrap();
}

[duskmoon314]

Thank you!

[timhughes]

I had to pull in tower-layer

use axum::{extract::Request, routing::get, Router, ServiceExt};
use tokio::net::TcpListener;
use tower_http::normalize_path::NormalizePathLayer;
use tower_layer::Layer;

#[tokio::main]
async fn main() {
    pub fn app_router() -> Router {
        Router::new().route("/", get(|| async { "hi" }))
    }
    let app = Router::new().nest("/api", app_router());
    let app = NormalizePathLayer::trim_trailing_slash().layer(app);

    let listener = TcpListener::bind("127.0.0.1:3000").await.unwrap();

    axum::serve(listener, ServiceExt::<Request>::into_make_service(app)) // <-- this
        .await
        .unwrap();
}