python socket server 并发（转）

import SocketServer, time, select, sys
from threading import Thread
COMMAND_HELLO = 1
COMMAND_QUIT = 2
# The SimpleRequestHandler class uses this to parse command lines.
class SimpleCommandProcessor:
    def __init__(self):
        pass
    def process(self, line, request):
        """Process a command"""
        args = line.split(' ')
        command = args[0].lower()
        args = args[1:]
        if command == 'hello':
            request.send('HELLO TO YOU TO!\n\r')
            return COMMAND_HELLO
        elif command == 'quit':
            request.send('OK, SEE YOU LATER\n\r')
            return COMMAND_QUIT
        else:
            request.send('Unknown command: "%s"\n\r' % command)
# SimpleServer extends the TCPServer, using the threading mix in
# to create a new thread for every request.
class SimpleServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
    # This means the main server will not do the equivalent of a
    # pthread_join() on the new threads. With this set, Ctrl-C will
    # kill the server reliably.
    daemon_threads = True
    # By setting this we allow the server to re-bind to the address by
    # setting SO_REUSEADDR, meaning you don't have to wait for
    # timeouts when you kill the server and the sockets don't get