CODEWITHSUNDEEP
pyzmq
jan
jan

Reputation: 1500

How to use subclasses of ZMQ sockets

I'd like to subclass the zmq.Socket class in order to automatically serialize Python objects before sending them and deserialize received messages. Now the docstring of zmq.Socket sais that in order to create a socket, I should create a context and then call

socket = context.socket(socket_type)

With this scheme, how can I use my own subclasses of zmq.Socket?

Upvotes: 0

Views: 338

Answers (2)

Dave Jones
Dave Jones

Reputation: 1130

There's a (sadly undocumented) _socket_class attribute on the zmq.Context class which can be used to customize the result of the socket(socktype) method. For example, to add CBOR serialization methods:

import cbor
import zmq

class CBORSocket(zmq.Socket):
    def send_cbor(self, obj, flags=0):
        return self.send(cbor.dumps(obj), flags=flags)

    def recv_cbor(self, flags=0):
        return cbor.loads(self.recv(flags=flags))

class CBORContext(zmq.Context):
    _socket_class = CBORSocket

def main():
    ctx = CBORContext()
    rep = ctx.socket(zmq.REP)
    req = ctx.socket(zmq.REQ)
    rep.bind('inproc://foo')
    req.connect('inproc://foo')
    req.send_cbor('Hello world!')
    print(rep.recv_cbor())

main()

Despite the lack of documentation for _socket_class, it does appear in one of the pyzmq example scripts although these don't appear to be used in the documentation itself. Still, I'm hoping that means it's official / unlikely to disappear arbitrarily!

Upvotes: 1

lusitania
lusitania

Reputation: 45

Are you aware of the send_pyobj and recv_pyobj methods in socket? They serialise Python objects with pickle.

Does this solve your issue? Otherwise it would be great if you could specify your question.

Upvotes: 0

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