axum/examples/global-404-handler/src/main.rs

//! Run with
//!
//! ```not_rust
//! cd examples && cargo run -p example-global-404-handler
//! ```

use axum::{
    http::StatusCode,
    response::{Html, IntoResponse},
    routing::get,
    Router,
};
use std::net::SocketAddr;
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};

#[tokio::main]
async fn main() {
    tracing_subscriber::registry()
        .with(tracing_subscriber::EnvFilter::new(
            std::env::var("RUST_LOG").unwrap_or_else(|_| "example_global_404_handler=debug".into()),
        ))
        .with(tracing_subscriber::fmt::layer())
        .init();

    // build our application with a route
    let app = Router::new().route("/", get(handler));

    // add a fallback service for handling routes to unknown paths
    let app = app.fallback(handler_404);

    // run it
    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();
}

async fn handler() -> Html<&'static str> {
    Html("<h1>Hello, World!</h1>")
}

async fn handler_404() -> impl IntoResponse {
    (StatusCode::NOT_FOUND, "nothing to see here")
}