Speno's Pythonic Avocado 18.2.2004

Teaching Twisted

I gave a short presentation at work today on the basics of Twisted. I tried to cover what I consider Twisted's core networking features: Protocols, Transports, Reactors, Factories and Deferreds.

Here's the same code I used to demonstrate the first four of those items:

from twisted.internet import protocol
from twisted.internet import reactor

class CountingEchoProtocol(protocol.Protocol):

    def dataReceived(self, data):
        self.transport.write(data)
        self.factory.incrementCount(len(data))
        data_written = self.factory.getCount()
        self.transport.write('Wrote %d bytes so far.\r\n' % data_written)

class CountingEchoFactory(protocol.ServerFactory):
   
    protocol = CountingEchoProtocol

    def __init__(self, max=24):
        self.count = 0
        self.max = max

    def incrementCount(self, length):
        self.count = self.count + length
        if self.count >= self.max:
            reactor.stop()

    def getCount(self):
        return self.count

ce_factory = CountingEchoFactory(25)
reactor.listenTCP(2323, ce_factory)
reactor.run()
print 'Wrote %d bytes total.' % ce_factory.getCount()

In prepartion for giving this informal talk, I spent about an hour or so just digging through the Twisted docs and/or the code answering my own questions. So hopefully my co-workers and I all got something from this.

Take care.