Developer Journal

This page is meant for collecting some important bits of knowledge, that do not fit anywhere else.

Twisted UDP IPv6 Support

Twisted UDP currently doesn't support IPv6 for UDP communications. There is a ticket for that, and most probably Twisted 14.0 will have official support. But for now a hack is needed:

In twisted/Twisted-13.x.x/twisted/internet/udp.py :

    def __init__(self, port, proto, interface='', maxPacketSize=8192, reactor=None):
        """
        Initialize with a numeric port to listen on.
        """
        base.BasePort.__init__(self, reactor)
        self.port = port
        self.protocol = proto
        self.maxPacketSize = maxPacketSize
        self.interface = interface
        self.setLogStr()
        self._connectedAddr = None
+       if interface and abstract.isIPv6Address(interface): ###
+          self.addressFamily = socket.AF_INET6 ###

and

    def doRead(self):
        """
        Called when my socket is ready for reading.
        """
        read = 0
        while read < self.maxThroughput:
            try:
                data, addr = self.socket.recvfrom(self.maxPacketSize)
            except socket.error as se:
                no = se.args[0]
                if no in _sockErrReadIgnore:
                    return
                if no in _sockErrReadRefuse:
                    if self._connectedAddr:
                        self.protocol.connectionRefused()
                    return
                raise
            else:
                read += len(data)
                try:
+                 addr = (addr[0], addr[1]) ###
                    self.protocol.datagramReceived(data, addr)
                except:
                    log.err()

This allows for simple unicast UDP communication. Works on Windows, Linux and Android.