Question

I’m trying to make a simple TCP server using Twisted ,which can do some interaction between diffirent client connections.The main code is as below:

#!/usr/bin/env python
from twisted.internet import protocol, reactor
from time import ctime

#global variables
PORT = 22334
connlist = {}    #store all the connections
ids = {}    #map the from-to relationships

class TSServerProtocol(protocol.Protocol):

    def dataReceived(self, data):
        from_id,to_id = data.split('|') #get the IDs from standard client input,which looks like "from_id|to_id"

        if self.haveConn(from_id):    #try to store new connections' informations
            pass
        else:
            self.setConn(from_id)
            self.setIds(from_id,to_id) 

        if to_id in self.csids.keys():                 
             self.connlist[to_id].transport.write(\
             "you get a message now!from %s \n" % from_id)    #if the to_id target found,push him a message.doesn't work as expected
    def setConn(self,sid):
        connlist[sid] = self

    #some other functions

factory = protocol.Factory()
factory.protocol = TSServerProtocol
print 'waiting from connetction...'
reactor.listenTCP(PORT, factory)
reactor.run()

As the comments mentioned,if a new client connection comes,I’ll store its connection handle in a global varaible connlist which is like

connlist = {a_from_id:a_conObj,b_from_id:b_conObj,....}

and also parse the input then map its from-to information in ids.Then I check whether there’s a key in the ids matches current “to_id”.if does,get the connection handle using connlist[to_id] and push a message to the target connection.But it doesn’t work.The message only shows in a same connection.Hope someone can show me some directions about this.

Thanks!

Answer 1

Each time a TCP connection is made, Twisted will create a unique instance of TSServerProtocol to handle that connection. So, you’ll only ever see 1 connection in TSServerProtocol. Normally, this is what you want but Factories can be extended to do the connection tracking you’re attempting to do here. Specifically, you can subclass Factory and override the buildProtocol() method to track instances of TSServerProtocol. The interrelationship between all the classes in Twisted takes a little time to learn and get used to. In particular, this piece of the standard Twisted documentation should be your best friend for the next while 😉