CODEWITHSUNDEEP
pythonpython-2.7inheritance
Dave
Dave

Reputation: 1436

Why can't I override this method in python?

I'm trying to override a python class (first time doing this), and I can't seem to override this method. When I run this, my recv method doesn't run. It runs the superclasses's method instead. What am I doing wrong here? (This is python 2.7 by the way.)

import socket

class PersistentSocket(socket.socket):
    def recv(self, count):
        print("test")
        return super(self.__class__, self).recv(count)

if __name__ == '__main__':
    s = PersistentSocket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect(('localhost', 2300))
    print(s.recv(1)

Upvotes: 4

Views: 2008

Answers (2)

jbatista
jbatista

Reputation: 2855

Picking on the explanation from @user2357112, one thing that seems to have helped is to do a delattr(self, 'recv') on the class constructor (inheriting from socket.SocketType) and then define you own recv method; for example:

class PersistentSocket(socket.SocketType):
    def __init__(self):
        """As usual."""
        delattr(self, 'recv')
    def recv(self, buffersize=1024, flags=0):
        """Your own implementation here."""
        return None

Upvotes: 0

user2357112
user2357112

Reputation: 280335

The socket type (officially socket.SocketType, though socket.socket happens to be the same object) makes the strange choice of implementing recv and a few other methods as instance attributes, rather than as normal methods in the class dict. In socket.SocketType.__init__, it sets a self.recv instance attribute that overrides the recv method you tried to define.

Upvotes: 5

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