Object-oriented networking

Question

I\'ve written a number of networking systems and have a good idea of how networking works. However I always end up having a packet receive function which is a giant switch stat

Answer 1

When you are doing OOP, you try to represent every thing as an object, right? So your protocol messages become objects too; you'll probably have a base class YourProtocolMessageBase which will encapsulate any message's behavior and from which you will inherit your polymorphically specialized messages. Then you just need a way to turn every message (i.e. every YourProtocolMessageBase instance) into a string of bytes, and a way to do reverse. Such methods are called serialization techniques; some metaprogramming-based implementations exist.

Quick example in Python:

from socket import *
sock = socket(AF_INET6, SOCK_STREAM)
sock.bind(("localhost", 1234))
rsock, addr = sock.accept()

Server blocks, fire up another instance for a client:

from socket import *
clientsock = socket(AF_INET6, SOCK_STREAM)
clientsock.connect(("localhost", 1234))

Now use Python's built-in serialization module, pickle; client:

import pickle
obj = {1: "test", 2: 138, 3: ("foo", "bar")}
clientsock.send(pickle.dumps(obj))

Server:

>>> import pickle
>>> r = pickle.loads(rsock.recv(1000))
>>> r
{1: 'test', 2: 138, 3: ('foo', 'bar')}

So, as you can see, I just sent over link-local a Python object. Isn't this OOP?

I think the only possible alternative to serializing is maintaining the bimap IDs ⇔ classes. This looks really inevitable.