Rust webserver

webserver.rs

use http_body_util::Full;
use hyper::server::conn::http1;
use hyper::{body::Bytes, service::service_fn, Request, Response};
use std::{convert::Infallible, error::Error, net::SocketAddr};
use tokio::net::TcpListener;

async fn hello(_: Request<hyper::body::Incoming>) -> Result<Response<Full<Bytes>>, Infallible> {
    Ok(Response::new(Full::new(Bytes::from("Hello World!"))))
}

fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
    tokio::runtime::Builder::new_current_thread()
        .worker_threads(1)
        .enable_io()
        .build()
        .unwrap()
        .block_on(tokio_main())
}

async fn tokio_main() -> Result<(), Box<dyn Error + Send + Sync>> {
    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));

    let listener = TcpListener::bind(addr).await?;

    loop {
        let (stream, _) = listener.accept().await?;

        tokio::task::spawn(async move {
            if let Err(err) = http1::Builder::new()
                .serve_connection(stream, service_fn(hello))
                .await
            {
                println!("Error serving connection: {:?}", err);
            }
        });
    }
}