An asyncio-based chat server

The asyncio Standard Library module is new in Python 3.4 and it is an effort at bringing some standardization around asynchronous I/O into the Standard Library. The asyncio library uses a co-routine based style of programming. It provides a powerful loop class, which our programs can submit prepared tasks, called co-routines, to, for asynchronous execution. The event loop handles the scheduling of the tasks and optimization of performance around blocking I/O calls.

It has built-in support for socket-based networking, which makes building a basic server a straightforward task. Let's see how this can be done. Create a new file called 5.1-chat_server-asyncio.py and save the following code in it:

import asyncio
import tincanchat

HOST = tincanchat.HOST
PORT = tincanchat.PORT
clients = []

class ChatServerProtocol(asyncio.Protocol):
  """ Each instance of class represents a client and the socket 
       connection to it. """

    def connection_made(self, transport...