Python asynchat Chat Example

• The handler.push method is thread-safe.
• The server implements broadcast to all the listening chat clients.
• Two chat clients implement send/read. This seemed easiest because Python doesn't have a simple way to do an asynchronous raw_input.
• Messages exchanged between client and server must be terminated by newlines.

chat_server.py

import asynchat
import asyncore
import socket
 
chat_room = {}
 
class ChatHandler(asynchat.async_chat):
    def __init__(self, sock):
        asynchat.async_chat.__init__(self, sock=sock, map=chat_room)
 
        self.set_terminator('\n')
        self.buffer = []
 
    def collect_incoming_data(self, data):
        self.buffer.append(data)
 
    def found_terminator(self):
        msg = ''.join(self.buffer)
        print 'Received:', msg
        for handler in chat_room.itervalues():
            if hasattr(handler, 'push'):
                handler.push(msg + '\n')
        self.buffer = []
 
class ChatServer(asyncore.dispatcher):
    def __init__(self, host, port):
        asyncore.dispatcher.__init__(self, map=chat_room)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.bind((host, port))
        self.listen(5)
 
    def handle_accept(self):
        pair = self.accept()
        if pair is not None:
            sock, addr = pair
            print 'Incoming connection from %s' % repr(addr)
            handler = ChatHandler(sock)
 
server = ChatServer('localhost', 5050)
 
print 'Serving on localhost:5050'
asyncore.loop(map=chat_room)

chat_client_send.py

import asynchat
import asyncore
import socket
import threading
 
class ChatClient(asynchat.async_chat):
 
    def __init__(self, host, port):
        asynchat.async_chat.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.connect((host, port))
 
        self.set_terminator('\n')
        self.buffer = []
 
    def collect_incoming_data(self, data):
        pass
 
    def found_terminator(self):
        pass
 
client = ChatClient('localhost', 5050)
 
comm = threading.Thread(target=asyncore.loop)
comm.daemon = True
comm.start()
 
while True:
    msg = raw_input('> ')
    client.push(msg + '\n')

chat_client_read.py

import asynchat
import asyncore
import socket
 
class ChatClient(asynchat.async_chat):
 
    def __init__(self, host, port):
        asynchat.async_chat.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.connect((host, port))
 
        self.set_terminator('\n')
        self.buffer = []
 
    def collect_incoming_data(self, data):
        self.buffer.append(data)
 
    def found_terminator(self):
        msg = ''.join(self.buffer)
        print 'Received:', msg
        self.buffer = []
 
client = ChatClient('localhost', 5050)
 
print 'Listening on localhost:5050'
asyncore.loop()