A simple echo server

As we work through this chapter, we'll find ourselves reusing several pieces of code, so to save ourselves from repetition, we'll set up a module with useful functions that we can reuse as we go along. Create a file called tincanchat.py and save the following code in it:

import socket

HOST = ''
PORT = 4040

def create_listen_socket(host, port):
    """ Setup the sockets our server will receive connection requests on """
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.bind((host, port))
    sock.listen(100)
    return sock

def recv_msg(sock):
    """ Wait for data to arrive on the socket, then parse into messages using b'\0' as message delimiter """
    data = bytearray()
    msg = ''
    # Repeatedly read 4096 bytes off the socket, storing the bytes
    # in data until we see a delimiter
    while not msg:
        recvd = sock.recv(4096)
        if not recvd:
            # Socket has...