python - 简单的 Twisted Echo 客户端

Question

我正在尝试在 Twisted 中编写一个简单的 Echo 客户端，它将键盘输入发送到服务器，并由用户自行输入“q”终止。简而言之，我只是想修改在 this page 上找到的简单回显客户端(和变体) .一点都不性感，只是基本款。

我正在为最基本的事件循环而苦苦挣扎。看起来我无法在循环中启动/停止 react 器，因为停止的 react 器不能 restarted .如果我不停止 react 堆，那么我将永远不会到达获取键盘输入的下一行。

如果能帮助我的 echo 客户端正常工作，我们将不胜感激。

from twisted.internet.protocol import ClientFactory
from twisted.protocols.basic import LineReceiver
from twisted.internet import reactor

class EchoClient(LineReceiver):
    end="Bye-bye!"
    def connectionMade(self):
        #only write and end transmission if the message isn't empty
        if len(self.factory.message) > 0:
            self.sendLine(self.factory.message)
            self.sendLine(self.end)
        else:
        #Else just terminate the connection
            self.transport.loseConnection()

    def lineReceived(self, line):
        print "receive:", line
        if line==self.end:
            self.transport.loseConnection()

class EchoClientFactory(ClientFactory):
    message = ""

    def buildProtocol(self, address):
        p = EchoClient()
        p.factory = self
        return p

    def clientConnectionFailed(self, connector, reason):
        reactor.stop()

    def clientConnectionLost(self, connector, reason):
        reactor.stop()

def main():

    s = raw_input('Text to send (''q'' to terminate): ')
    while s != 'q':
        factory = EchoClientFactory()
        factory.message = s
        reactor.connectTCP('localhost', 8000, factory)

        #This is bad because reactor cannot be restarted once it's been stopped
        reactor.run()

        s = raw_input('Text to send(''q'' to terminate): ')

if __name__ == '__main__':
    main()

Answer 1

根据经验 - 在极少数情况下您会想要重新启动或停止 reactor，除非您完全终止您的程序。如果您遇到一段会导致阻塞的代码，例如数据库访问、长时间计算或在您的情况下是 raw_input，您必须:找到一个扭曲的替代方案(在数据库的情况下为 twisted.enterprise.adabi)或使其兼容扭曲。“解除阻塞”代码的最简单方法是利用 twisted.internet.threads 中的 deferToThread 将阻塞位移动到线程中。考虑这个例子:

from twisted.internet.threads import deferToThread as __deferToThread
from twisted.internet import reactor

def mmprint(s):
    print(s)

class TwistedRAWInput(object):
    def start(self,callable,terminator):
        self.callable=callable
        self.terminator=terminator
        self.startReceiving()
    def startReceiving(self,s=''):
        if s!=self.terminator:
            self.callable(s)
            __deferToThread(raw_input,':').addCallback(self.startReceiving)


tri = TwistedRAWInput()
reactor.callWhenRunning(tri.start,mmprint,'q')
reactor.run()

您永远不必停止 reactor，因为 raw_input 会在外部线程中发生，回调会在每一行上延迟。