Middleware that change the request body have poor usability #1110

davidpdrsn · 2022-06-20T13:46:42Z

We've heard from several people who try to use tower_http::limit::RequestBodyLimitLayer that the implications are hard to understand.

For example breaking your Router into functions is quite common. Something like:

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

    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
    axum::Server::bind(&addr)
        .serve(app.into_make_service())
        .await
        .unwrap();
}

fn my_routes() -> Router {
    Router::new()
}

Adding RequestBodyLimitLayer like so

let app = my_routes().layer(RequestBodyLimitLayer::new(1024));

should just work but produces a rather confusing error:

    Checking example-hello-world v0.1.0 (/Users/davidpdrsn/dev/major/axum/examples/hello-world)
error[E0277]: the trait bound `Route: tower_service::Service<Request<http_body::limited::Limited<_>>>` is not satisfied
  --> hello-world/src/main.rs:13:27
   |
13 |     let app = my_routes().layer(RequestBodyLimitLayer::new(1024));
   |                           ^^^^^ the trait `tower_service::Service<Request<http_body::limited::Limited<_>>>` is not implemented for `Route`
   |
   = help: the following implementations were found:
             <Route<B, E> as tower_service::Service<Request<B>>>
   = note: required because of the requirements on the impl of `tower_service::Service<Request<_>>` for `RequestBodyLimit<Route>`

The solution is instead to write

fn my_routes() -> Router<http_body::Limited<Body>> {
    Router::new()
}

but that isn't obvious and ideally shouldn't be necessary.

We should think about ways to improve that experience.

The text was updated successfully, but these errors were encountered:

davidpdrsn · 2022-08-22T12:08:01Z

I think this is closely related to #1154. If axum had its own body type, and a way to construct that from any B: http_body::Body then we could use that everywhere, even if you applied middleware.

That is something we'll have to explore once the development of hyper 1.0 (and hyper-utils) is further along. Hyper 1.0 will require a breaking release of axum anyway, so I think we should wait with this until we're closer to that happening.

I'm gonna remove this from the 0.6 milestone.

avdb13 · 2022-09-15T16:57:58Z

why does ContentLengthLimit exist in Axum when we have tower_http::limit::RequestBodyLimitLayer in Tower, on which Axum relies anyway?
What are their biggest differences other than that the former has the tradeoff that its argument needs to be a const?

davidpdrsn · 2022-09-18T18:59:35Z

why does ContentLengthLimit exist in Axum when we have tower_http::limit::RequestBodyLimitLayer in Tower, on which Axum relies anyway?
What are their biggest differences other than that the former has the tradeoff that its argument needs to be a const?

Mostly history. ContentLengthLimit was made before RequestBodyLimitLayer existed. It also has a few differences

It doesn't change the type of your Router. Adding RequestBodyLimitLayer changes the Router type to Router<_, http_body::Limited<_>>. Thats what this issue is about.
It doesn't permit streaming requests, which RequestBodyLimitLayer does.

I tried previously to implement ContentLengthLimit on top of http_body::Limited but couldn't do it because of limitations in 0.5. However in 0.6 FromRequest gets an owned Request<B> which it can take a part and change the body type of. So it might be possible to bridge the cap further between the two and make ContentLengthLimit support streaming requests.

Edit: Its possible #1389!

avdb13 · 2022-09-22T12:54:26Z

I'm trying to use tower_http::limit::RequestBodyLimitLayer on a single handler but I get the following error:

error[E0277]: the trait bound `axum::handler::Layered<RequestBodyLimit<IntoService<fn(Extension<Arc<App>>, Multipart) -> impl Future<Output = axum::response::Redirect> {handlers::creat
e_post}, (Extension<Arc<App>>, Multipart), _>>, (Extension<Arc<App>>, Multipart)>: Handler<_, _>` is not satisfied
   --> src/routes.rs:27:32
    |
27  |         .route("/:board", post(create_post))
    |                           ---- ^^^^^^^^^^^ the trait `Handler<_, _>` is not implemented for `axum::handler::Layered<RequestBodyLimit<IntoService<fn(Extension<Arc<App>>, Multipart
) -> impl Future<Output = axum::response::Redirect> {handlers::create_post}, (Extension<Arc<App>>, Multipart), _>>, (Extension<Arc<App>>, Multipart)>`
    |                           |
    |                           required by a bound introduced by this call
    |
    = help: the trait `Handler<T, ReqBody>` is implemented for `axum::handler::Layered<S, T>`
note: required by a bound in `post`
   --> /home/mikoto/.cargo/registry/src/github.aa529453975.workers.dev-1ecc6299db9ec823/axum-0.5.13/src/routing/method_routing.rs:400:1
    |
400 | top_level_handler_fn!(post, POST);
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `post`
    = note: this error originates in the macro `top_level_handler_fn` (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0277]: the trait bound `Router<http_body::Limited<axum::body::Body>>: tower_service::Service<Request<axum::body::Body>>` is not satisfied
  --> src/main.rs:71:16
   |
71 |         .serve(router.into_make_service())
   |          ----- ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `tower_service::Service<Request<axum::body::Body>>` is not implemented for `Router<http_body::Limited<axum::body::Body>>`
   |          |
   |          required by a bound introduced by this call
   |
   = help: the trait `tower_service::Service<Request<B>>` is implemented for `Router<B>`
   = note: required because of the requirements on the impl of `hyper::service::http::HttpService<axum::body::Body>` for `Router<http_body::Limited<axum::body::Body>>`
   = note: required because of the requirements on the impl of `hyper::service::make::MakeServiceRef<hyper::server::tcp::addr_stream::AddrStream, axum::body::Body>` for `IntoMakeServic
e<Router<http_body::Limited<axum::body::Body>>>`

error[E0277]: the trait bound `hyper::common::exec::Exec: hyper::common::exec::NewSvcExec<hyper::server::tcp::addr_stream::AddrStream, IntoMakeServiceFuture<Router<http_body::Limited<a
xum::body::Body>>>, Router<http_body::Limited<axum::body::Body>>, hyper::common::exec::Exec, hyper::server::server::NoopWatcher>` is not satisfied
  --> src/main.rs:71:43
   |
71 |           .serve(router.into_make_service())
   |  ___________________________________________^
72 | |         .await
   | |______________^ the trait `hyper::common::exec::NewSvcExec<hyper::server::tcp::addr_stream::AddrStream, IntoMakeServiceFuture<Router<http_body::Limited<axum::body::Body>>>, Route
r<http_body::Limited<axum::body::Body>>, hyper::common::exec::Exec, hyper::server::server::NoopWatcher>` is not implemented for `hyper::common::exec::Exec`
   |
   = help: the trait `hyper::common::exec::NewSvcExec<I, N, S, E, W>` is implemented for `hyper::common::exec::Exec`
   = note: required because of the requirements on the impl of `Future` for `Server<hyper::server::tcp::AddrIncoming, IntoMakeService<Router<http_body::Limited<axum::body::Body>>>>`
   = note: required because of the requirements on the impl of `IntoFuture` for `Server<hyper::server::tcp::AddrIncoming, IntoMakeService<Router<http_body::Limited<axum::body::Body>>>>
`
help: remove the `.await`
   |
71 -         .serve(router.into_make_service())
71 +         .serve(router.into_make_service())
   |

error[E0277]: the trait bound `Router<http_body::Limited<axum::body::Body>>: tower_service::Service<Request<axum::body::Body>>` is not satisfied
  --> src/main.rs:71:10
   |
71 |         .serve(router.into_make_service())
   |          ^^^^^ the trait `tower_service::Service<Request<axum::body::Body>>` is not implemented for `Router<http_body::Limited<axum::body::Body>>`
   |
   = help: the trait `tower_service::Service<Request<B>>` is implemented for `Router<B>`
   = note: required because of the requirements on the impl of `hyper::service::http::HttpService<axum::body::Body>` for `Router<http_body::Limited<axum::body::Body>>`
   = note: required because of the requirements on the impl of `hyper::service::make::MakeServiceRef<hyper::server::tcp::addr_stream::AddrStream, axum::body::Body>` for `IntoMakeServic
e<Router<http_body::Limited<axum::body::Body>>>`

This is what my router looks like:

pub fn routes(app: Arc<App>) -> Router<http_body::Limited<Body>> {
    let create_post = handlers::create_post.layer(RequestBodyLimitLayer::new(
        (app.config.security.validate_upload_limit()).unwrap(),
    ));

    Router::new()
        ...
        .route("/:board", post(create_post))
        .layer(TraceLayer::new_for_http())
        .layer(Extension(app))
        .fallback(handlers::fallback.into_service())
}

avdb13 · 2022-09-22T13:07:52Z

The following compiles fine:

pub fn routes(app: Arc<App>) -> Router {
    let create_post = handlers::create_post;

    Router::new()
        ...
        .route("/:board", post(create_post))
        .layer(TraceLayer::new_for_http())
        // .layer(RequestBodyLimitLayer::new(
        //     (app.config.security.validate_upload_limit()).unwrap(),
        // ))
        .layer(Extension(app))
        .fallback(handlers::fallback.into_service())
}

davidpdrsn · 2022-09-22T15:49:33Z

@avdb13 please open a separate issue/discussion about that and please include a minimal reproducible example that we can run.

davidpdrsn · 2023-03-20T20:33:59Z

I'd say this has been solved by #1751. TLDR: in axum 0.7 the B type parameter has been removed and we instead use our own Body type. So adding new middleware never changes the request body type.

davidpdrsn added C-musings Category: musings about a better world A-axum labels Jun 20, 2022

davidpdrsn added this to the 0.6 milestone Jun 25, 2022

davidpdrsn mentioned this issue Jul 11, 2022

Remove request body type param #1154

Closed

2 tasks

davidpdrsn self-assigned this Jul 11, 2022

davidpdrsn mentioned this issue Jul 11, 2022

feat(body): add Body::wrap_body hyperium/hyper#2913

Closed

davidpdrsn added the E-hard Call for participation: Experience needed to fix: Hard / a lot label Jul 13, 2022

davidpdrsn removed this from the 0.6 milestone Aug 22, 2022

davidpdrsn mentioned this issue Aug 25, 2022

Hyper 1.0 support #1325

Closed

davidpdrsn mentioned this issue Sep 18, 2022

Support streaming/chunked requests in ContentLengthLimit #1389

Merged

davidpdrsn mentioned this issue Sep 24, 2022

Tracking: Improvements to DefaultBodyLimit #1409

Closed

3 tasks

This was referenced Nov 27, 2022

v0.7.0 #1583

Merged

Add axum_core::body::Body #1584

Merged

davidpdrsn mentioned this issue Feb 12, 2023

Remove B type param #1751

Merged

1 task

avdb13 mentioned this issue Mar 5, 2023

the trait Clone is not implemented for http_body::Limited<hyper::Body> #1817

Closed

davidpdrsn closed this as completed Mar 20, 2023

yokomizor mentioned this issue Sep 28, 2023

Axum Integration for BoxBody or impl HttpBody. leptos-rs/leptos#1793

Closed

markgomez mentioned this issue Jan 6, 2024

RequestBodyLimitLayer when applied via ServiceBuilder won't compile in v0.7 #2492

Open

ttys3 mentioned this issue Feb 3, 2025

axum: allow body types other than axum::body::Body in Services passed to serve #3205

Open

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Middleware that change the request body have poor usability #1110

Middleware that change the request body have poor usability #1110

davidpdrsn commented Jun 20, 2022 •

edited

Loading

davidpdrsn commented Aug 22, 2022

avdb13 commented Sep 15, 2022

davidpdrsn commented Sep 18, 2022 •

edited

Loading

avdb13 commented Sep 22, 2022

avdb13 commented Sep 22, 2022

davidpdrsn commented Sep 22, 2022

davidpdrsn commented Mar 20, 2023

Middleware that change the request body have poor usability #1110

Middleware that change the request body have poor usability #1110

Comments

davidpdrsn commented Jun 20, 2022 • edited Loading

davidpdrsn commented Aug 22, 2022

avdb13 commented Sep 15, 2022

davidpdrsn commented Sep 18, 2022 • edited Loading

avdb13 commented Sep 22, 2022

avdb13 commented Sep 22, 2022

davidpdrsn commented Sep 22, 2022

davidpdrsn commented Mar 20, 2023

davidpdrsn commented Jun 20, 2022 •

edited

Loading

davidpdrsn commented Sep 18, 2022 •

edited

Loading