Axum v0.8.4 h2c サーバー

Cargo.toml

[dependencies]
axum = { version = "0.8", features = "http2" }
tokio = { version = "1", features = ["full"] }
hyper = { version = "1", features = ["http2", "server"] }
hyper-util = { version = "0.1", features = ["tokio"] }

main.rs

use axum::{routing::get, Router};
use hyper::server::conn::http2;
use hyper_util::{rt::tokio::{TokioIo, TokioExecutor}, service::TowerToHyperService};
use std::net::SocketAddr;
use tokio::net::TcpListener;

#[tokio::main]
async fn main() {
    // Axum アプリ
    let app = Router::new().route("/", get(handler));
    let service = TowerToHyperService::new(app.into_service());

    // バインド（HTTP/2 over cleartext = h2c）
    let addr = SocketAddr::from(([127, 0, 0, 1], 8080));
    let listener = TcpListener::bind(addr).await.unwrap();
    println!("🚀 h2c server listening on http://{addr}");

    loop {
        let (tcp, _) = listener.accept().await.unwrap();
        let io = TokioIo::new(tcp);
        let executor = TokioExecutor::new();
        let service = service.clone();
        tokio::spawn(async move {
            if let Err(err) = http2::Builder::new(executor)
                .serve_connection(io, service)
                .await
            {
                eprintln!("❌ h2c connection error: {err:?}");
            }
        });
    }
}

async fn handler() -> &'static str {
    "Hello from h2c server!"
}