tokio_spawn_concurrent_tcp_echo_server.rs

1use tokio::net::TcpListener;
2use tokio::io::{AsyncReadExt, AsyncWriteExt};
3
4#[tokio::main]
5async fn main() -> Result<(), Box<dyn std::error::Error>> {
6    let listener = TcpListener::bind("127.0.0.1:8080").await?;
7
8    loop {
9        let (mut socket, _) = listener.accept().await?;
10
11        tokio::spawn(async move {
12            let mut buf = [0; 1024];
13
14            // In a loop, read data from the socket and write the data back.
15            loop {
16                let n = match socket.read(&mut buf).await {
17                    // socket closed
18                    Ok(n) if n == 0 => return,
19                    Ok(n) => n,
20                    Err(e) => {
21                        eprintln!("failed to read from socket; err = {:?}", e);
22                        return;
23                    }
24                };
25
26                // Write the data back
27                if let Err(e) = socket.write_all(&buf[0..n]).await {
28                    eprintln!("failed to write to socket; err = {:?}", e);
29                    return;
30                }
31            }
32        });
33    }
34}