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

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

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

#[tokio::main]
async fn main() {
    tracing_subscriber::registry()
        .with(
            tracing_subscriber::EnvFilter::try_from_default_env()
                .unwrap_or_else(|_| format!("{}=debug", env!("CARGO_CRATE_NAME")).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 listener = tokio::net::TcpListener::bind("127.0.0.1:3000")
        .await
        .unwrap();
    tracing::debug!("listening on {}", listener.local_addr().unwrap());
    axum::serve(listener, app).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")
}