asyncore udp 编程

asyncore 是python自带的异步编程框架，非常适合进行支持select的socket编程，又不用注意很多异步编程的细节。自带的文档的 例子是tcp协议的编程，下面是一个udp协议的例子：


import asyncore, socket

class Client(asyncore.dispatcher):
    def __init__(self, localAddr, remoteAddr):
        asyncore.dispatcher.__init__(self)
        self.localAddr = localAddr
        self.remoteAddr = remoteAddr
        self.pendingPacket = []
        self.create_socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.bind(localAddr)

    def send(self, packet):
        self.pendingPacket.append(packet)

    def writeable(self):
        return len(self.pendingPacket) > 0

    def handle_write(self):
        if len(self.pendingPacket) > 0:
            p = self.pendingPacket.pop(0)
            self.sendto(p, remoteAddr)

    def handle_read(self):
         data, addr = self.recvfrom(64*1024)
         print repr(data), repr(addr)

    def handle_close(self):
        self.close()

    def handle_error(self):
        logging.error('bad')

    def handle_connect(self):
        pass

def main():
    qq = Client(('', 4000), ('127.0.0.0', 8000))
    qq.send('')
    while 1:
        try:   
            asyncore.loop(timeout=1.0, count = 1)
        except KeyboardInterrupt:
            break
if __name__ == '__main__':
    main()