axum

# axum

`axum` is an HTTP routing and request-handling library that focuses on ergonomics and modularity.

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[![Crates.io](https://img.shields.io/crates/v/axum)](https://crates.io/crates/axum)
[![Documentation](https://docs.rs/axum/badge.svg)][docs]

More information about this crate can be found in the [crate documentation][docs].

## High level features

- Route requests to handlers with a macro free API.
- Declaratively parse requests using extractors.
- Simple and predictable error handling model.
- Generate responses with minimal boilerplate.
- Take full advantage of the [`tower`] and [`tower-http`] ecosystem of
  middleware, services, and utilities.

In particular the last point is what sets `axum` apart from other libraries / frameworks.
`axum` doesn't have its own middleware system but instead uses
[`tower::Service`]. This means `axum` gets timeouts, tracing, compression,
authorization, and more, for free. It also enables you to share middleware with
applications written using [`hyper`] or [`tonic`].

## ⚠ Breaking changes ⚠

We are currently working towards axum 0.9 so the `main` branch contains breaking
changes. See the [`0.8.x`] branch for what's released to crates.io.

[`0.8.x`]: https://github.com/tokio-rs/axum/tree/v0.8.x

## Usage example

```rust
use axum::{
    routing::{get, post},
    http::StatusCode,
    Json, Router,
};
use serde::{Deserialize, Serialize};

#[tokio::main]
async fn main() {
    // initialize tracing
    tracing_subscriber::fmt::init();

    // build our application with a route
    let app = Router::new()
        // `GET /` goes to `root`
        .route("/", get(root))
        // `POST /users` goes to `create_user`
        .route("/users", post(create_user));

    // run our app with hyper, listening globally on port 3000
    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
    axum::serve(listener, app).await;
}

// basic handler that responds with a static string
async fn root() -> &'static str {
    "Hello, World!"
}

async fn create_user(
    // this argument tells axum to parse the request body
    // as JSON into a `CreateUser` type
    Json(payload): Json<CreateUser>,
) -> (StatusCode, Json<User>) {
    // insert your application logic here
    let user = User {
        id: 1337,
        username: payload.username,
    };

    // this will be converted into a JSON response
    // with a status code of `201 Created`
    (StatusCode::CREATED, Json(user))
}

// the input to our `create_user` handler
#[derive(Deserialize)]
struct CreateUser {
    username: String,
}

// the output to our `create_user` handler
#[derive(Serialize)]
struct User {
    id: u64,
    username: String,
}
```

You can find this [example][readme-example] as well as other example projects in
the [example directory][examples].

See the [crate documentati