twisted.py

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

import msgpack

class UserHandler:
    def hello0(self):
        print "hello!"
        return 0

    def hello1(self, a):
        print "hello1!!"
        print a
        return 1

class MessagePackRPCProtocol(protocol.Protocol):
    def __init__(self):
        self.packer = msgpack.Packer()
        self.unpacker = msgpack.Unpacker()
            
    def dataReceived(self, data):
        if len(data) <= 0:
            return
        self.unpacker.feed(data)
        for msg in self.unpacker:
            reply = self.messageReceived(msg)

    def messageReceived(self, msg):
        if len(msg) != 4:
            raise Exception("Invalid Protocol")
        msgtype = msg[0]
        if msgtype != 0:
            raise Exception("request needed, but requested other type")
        msgid   = msg[1]
        method  = msg[2]
        args    = msg[3]

        result = self.callMethod(method, args)
        response = self.packer.pack([1, msgid, None, result])

        self.transport.write(response)

    def callMethod(self, method, args):
        try:
            func = getattr(handler, method)
        except AttributeError:
            raise Exception("missing function")
        if not callable(func):
            raise Exception("function not callable")

        if len(args) == 0:
            return func()
        else:
            return func(args)

class MessagePackRPCFactory(protocol.Factory):
    protocol = MessagePackRPCProtocol

    def __init__(self, userHandler):
        self.userHandler = userHandler

    def buildProtocol(self, addr):
        t = protocol.Factory.buildProtocol(self, addr)
        t.userHandler = self.userHandler
        return t

handler = UserHandler()
factory = MessagePackRPCFactory(handler)
reactor.listenTCP(1985, factory)
reactor.run()