TCP Networking

A simple TCP client and server application: echo

The following code is based on the examples provided by the documentation on std::net::TcpListener. This server application will listen to incoming requests and send back all incoming data, thus acting as an “echo” server. The client application will send a small message and expect a reply with the same contents.

server:

use std::thread;
use std::net::{TcpListener, TcpStream, Shutdown};
use std::io::{Read, Write};

fn handle_client(mut stream: TcpStream) {
    let mut data = [0 as u8; 50]; // using 50 byte buffer
    while match stream.read(&mut data) {
        Ok(size) => {
            // echo everything!
            stream.write(&data[0..size]).unwrap();
            true
        },
        Err(_) => {
            println!("An error occurred, terminating connection with {}", stream.peer_addr().unwrap());
            stream.shutdown(Shutdown::Both).unwrap();
            false
        }
    } {}
}

fn main() {
    let listener = TcpListener::bind("0.0.0.0:3333").unwrap();
    // accept connections and process them, spawning a new thread for each one
    println!("Server listening on port 3333");
    for stream in listener.incoming() {
        match stream {
            Ok(stream) => {
                println!("New connection: {}", stream.peer_addr().unwrap());
                thread::spawn(move|| {
                    // connection succeeded
                    handle_client(stream)
                });
            }
            Err(e) => {
                println!("Error: {}", e);
                /* connection failed */
            }
        }
    }
    // close the socket server
    drop(listener);
}

client:

use std::net::{TcpStream};
use std::io::{Read, Write};
use std::str::from_utf8;

fn main() {
    match TcpStream::connect("localhost:3333") {
        Ok(mut stream) => {
            println!("Successfully connected to server in port 3333");

            let msg = b"Hello!";

            stream.write(msg).unwrap();
            println!("Sent Hello, awaiting reply...");

            let mut data = [0 as u8; 6]; // using 6 byte buffer
            match stream.read_exact(&mut data) {
                Ok(_) => {
                    if &data == msg {
                        println!("Reply is ok!");
                    } else {
                        let text = from_utf8(&data).unwrap();
                        println!("Unexpected reply: {}", text);
                    }
                },
                Err(e) => {
                    println!("Failed to receive data: {}", e);
                }
            }
        },
        Err(e) => {
            println!("Failed to connect: {}", e);
        }
    }
    println!("Terminated.");
}