Concurrent implementation of the Daytime Protocol in Rust

November 16, 2015

When learning a language, I rewrite small programs I’ve previously written to jumpstart my learning. Implementing a concurrent Daytime server has proved particularly useful because it uses both sockets and threads. If a language has good socket and threading libraries, it is likely a good language.

Previously, I demonstrated a Haskell implementation. Here’s an example in Rust:

extern crate time;

use std::time::Duration;
use std::io::Write;
use std::net::{TcpListener, TcpStream};
use std::thread;

fn handle_client(mut stream: TcpStream) {
    let date = time::strftime("%F %T\n", &time::now_utc()).unwrap().to_string();
    let _ = stream.write(date.as_bytes());
}

fn main() {
    let listener = TcpListener::bind("127.0.0.1:13").unwrap();

    for stream in listener.incoming() {
        match stream {
            Ok(stream) =>  {
                thread::spawn(move || {
                    // connection succeeded
                    thread::sleep(Duration::new(1,0));
                    handle_client(stream)
                });
            }
            Err(_) => { /* connection failed */ },
        }
    }

    drop(listener);
}

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