TCP roundtrip using async_std

main.rs

use anyhow::Result;
use async_std::{
  io,
  net::{TcpListener, TcpStream},
  prelude::*,
  task,
};

fn main() -> Result<()> {
    task::spawn(async move {
        let listener = TcpListener::bind("127.0.0.1:8080").await.unwrap();
        println!("Listening on {}", listener.local_addr().unwrap());

        let mut incoming = listener.incoming();

        while let Some(stream) = incoming.next().await {
            let stream = stream.unwrap();
            task::spawn(async {
                println!("Accepted from: {}", stream.peer_addr().unwrap());

                let mut reader = stream.clone();
                let mut writer = stream;
                io::copy(&mut reader, &mut writer).await.unwrap();
            });
        }
    });

    task::block_on(async {
        let mut stream = TcpStream::connect("127.0.0.1:8080").await?;
        println!("Connected to {}", &stream.peer_addr()?);

        let msg = "hello world";
        println!("<- {}", msg);
        stream.write_all(msg.as_bytes()).await?;

        let mut buf = vec![0u8; 1024];
        let n = stream.read(&mut buf).await?;
        println!("-> {}\n", String::from_utf8_lossy(&buf[..n]));

        Ok(())
    })
}