gistfile1.rs

use std::net::{TcpListener, TcpStream};
use std::thread;
use std::io::{stderr,Write,Read};
use std::env::args;

macro_rules! unwrap_fmt {
    ($expr:expr) => (match $expr {
        Ok(val) => val,
        Err(err) => panic!("{}", err)
    })
}

fn server(listen_addr: &str) {
    println!("Listening on {} ...", listen_addr);
    let listener = unwrap_fmt!(TcpListener::bind(listen_addr));
    for stream in listener.incoming() {
        match stream {
            Ok(stream) => {
                thread::spawn(|| {
                    handle_client(stream)
                });
            }
            Err(e) => {
                let _ = write!(&mut stderr(), "{}", e);
            }
        }
    }
}

fn main() {
    let args = args().collect::<Vec<_>>();
    if args.len() != 2 {
        println!("usage: {} listen_addr", args[0]);
        return;
    }
    server(&args[1]);
}

fn handle_client(mut stream: TcpStream) {
    println!("Connection from {}", stream.peer_addr().unwrap());
    let mut total = 0us;
    for b in unwrap_fmt!(stream.try_clone()).bytes() {
        total += 1;
        unwrap_fmt!(stream.write(&[unwrap_fmt!(b)]));
    }
    println!("Echoed {} bytes to {}",
             total, stream.peer_addr().unwrap());
}