axum --- web application framework

Question

axum

axum is a web application framework that focuses on ergonomics and modularity.

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

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 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.

Usage example

use axum::{prelude::*, response::IntoResponse, http::StatusCode};
use serde::{Deserialize, Serialize};
use std::net::SocketAddr;

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

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

    // run our app with hyper
    // `axum::Server` is a re-export of `hyper::Server`
    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
    tracing::debug!("listening on {}", addr);
    axum::Server::bind(&addr)
        .serve(app.into_make_service())
        .await
        .unwrap();
}

// 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
    extract::Json(payload): extract::Json<CreateUser>,
) -> impl IntoResponse {
    // insert your application logic here
    let user = User {
        id: 1337,
        username: payload.username,
    };

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

See the crate documentation for way more examples.

About

Ergonomic and modular web framework built with Tokio, Tower, and Hyper

code repository

https://github.com/tokio-rs/axum