Python的asyncore客户端定期向服务器发送数据

Question

我需要连接到一个服务器（比如说 smpp 服务器），并每 2 秒发送一次数据，下面是我的代码：

import asyncore, socket, threading, time

class SClient(asyncore.dispatcher):
    buffer = ""
    t = None

    def __init__(self, host):
        asyncore.dispatcher.__init__(self)
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.connect( (host, 25) )

        print "sending data from __init__"
        self.sendCommand("data_init")
        self.t = SenderThread(self)
        self.t.start()

    def sendCommand(self, command):
        self.buffer = command

    def handle_close(self):
        self.close()
        self.t.stop()

    def handle_read(self):
        print self.recv(8192)

    def writable(self):
        print 'asking for writable ? len='+str(len(self.buffer))
        return (len(self.buffer) > 0)

    def handle_write(self):
        print "writing to socket"
        sent = self.send(self.buffer)
        self.buffer = self.buffer[sent:]
        print "wrote "+str(sent)+" to socket"

class SenderThread(threading.Thread):
    _stop = False

    def __init__(self, client):
        super(SenderThread,self).__init__()
        self.client = client

    def stop(self):
        self._stop = True

    def run(self):
        counter = 0
        while self._stop == False:
            counter += 1
            time.sleep(1)
            if counter == 2:
                print "sending data from thread"
                self.client.sendCommand("data_thread")
                counter = 0

client = SClient('127.0.0.1')
asyncore.loop()

这是运行时的输出：

$ python test.py 
sending data from __init__
asking for writable ? len=9
writing to socket
wrote 9 to socket
asking for writable ? len=0
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
asking for writable ? len=11
writing to socket
wrote 11 to socket
asking for writable ? len=0
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
asking for writable ? len=11
writing to socket
wrote 11 to socket
asking for writable ? len=0
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread
sending data from thread

我的线程每 2 秒通过一个叫 buffer 的变量向服务器发送数据，但 asyncore 每 1 分钟才调用一次 writable 和 handle_write，我不明白为什么它不在 buffer 被线程填充后就立刻取出数据？

Answer 1

看看这个asyncore loop方法的文档。

timeout参数是用来设置select()或poll()调用的超时时间，单位是秒；默认的超时时间是30秒。

它每30秒才会触发一次handle_write。