udp broadcast example, please

[Jp Calderone]

On Wed, Dec 17, 2003 at 01:22:25PM +0200, Torsten Rueger wrote:
> Moi,
> 
> sorry, but I've searched and searched to find exact information on how 
> to do a simple udp broadcast client/server, but can find it:
> 
> I want to have a thread pinging (very small message) and possibly the 
> same thread receiving maybe with a 1 second timeout. And the same code 
> should be able to run as multiple instances on the same machine.
> 
> Could someone with experience please post the 10 lines to make this 
> happen. Please no general comments or things that "should" work. I've 
> tried for hours with various socket options and addresses, so I would 
> very much appreciate working code.
> 

  No threads, but maybe it's good enough anyway:

    import sys
    from socket import SOL_SOCKET, SO_BROADCAST

    from twisted.internet import reactor
    from twisted.internet import protocol
    from twisted.internet import task
    from twisted.python import log

    log.startLogging(sys.stdout)

    port = 7154

    class BroadcastingDatagramProtocol(protocol.DatagramProtocol):

        port = port

        def startProtocol(self):
            self.transport.socket.setsockopt(SOL_SOCKET, SO_BROADCAST, True)
            self.call = task.LoopingCall(self.tick)
            self.dcall = self.call.start(1.0)

        def stopProtocol(self):
            self.call.stop()

        def tick(self):
            self.transport.write(self.getPacket(), ("<broadcast>", self.port))

	def getPacket(self):
            return "Some bytes for you"

        def datagramReceived(self, data, addr):
            print "Received", repr(data)

    reactor.listenUDP(port, BroadcastingDatagramProtocol())
    reactor.run()

  Jp