Should `Request<B>` and `Response<B>` implement `Body`?

Open
  • Is something wrong?
#48 3 comments 2 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
35/100
Issue type
Refactor
Clarity
Mostly clear
Activity status
Stale
Tech stack
rust
Domain
networking

Research direction

Start by reviewing the Body implementations for Request<B> and Response<B>, then inspect the linked axum src/body.rs and src/response/mod.rs references. Determine whether removing those implementations avoids the demonstrated metadata loss and assess the breaking-change impact before deciding what tests or API updates are needed.

Written by the indexing model from the issue text.

Description

Today I discovered an unfortunate interaction between axum and http-body.

In axum you're able to write this:

use axum::{
    body::{box_body, Body, BoxBody},
    handler::get,
    http::Response,
    Router,
};

let app = Router::new().route(
    "/",
    get(|| async {
        // Build a response with a header.
        let response: Response<Body> = Response::builder()
            .header("x-foo", "foo")
            .body(Body::empty())
            .unwrap();

        // Since `Response<B>` implements `Body`, we can use `box_body` to
        // convert it into a `BoxBody`.
        let body: BoxBody = box_body(response);

        // And because `BoxBody` implements `IntoResponse` we can return it
        // from handlers.
        //
        // However `impl IntoResponse for BoxBody` simply does
        // `Response::new(self)` thus removing headers, status, etc.
        body
    }),
);

So because Response<B> implements Body it can be used with box_body but that ends up removing everything from the response except the body. I think being able to return bodies directly from axum handlers is a nice feature its just unfortunate that this particular thing compiles.

BoxBody's IntoResponse impl is here.

One could say "well just don't do this" but would be nice if it didn't compile at all, which could be done by removing impl Body for {Response, Request}<B>. Thats of course a breaking change 😞

Dominant language
Rust
Stars
173
Forks
71
Avg merge
1d 12h
Merged PRs (30d)
1

Getting set up

This project ships no dev container, Dockerfile or contributing guide, so setting up is up to you: start from its README, and see our first-contribution guide for the general steps.

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from hyperium/http-body

All issues in hyperium/http-body

Similar issues

More Rust issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.