How to correctly determine the class of an object received from the network in python?

Question

Python

I guess in python, due to different entry points or namespaces, classes begin to differ. But let's move on to a simple example:
m2.py

import pickle
from m1 import Ab

if __name__ == '__main__':
    ab = Ab()

    with open('data.pickle', 'wb') as f:
        pickle.dump(ab, f)

m1.py

import pickle

class Ab:
    def __init__(self):
        pass

class DataReader:
    def __init__(self):
        pass

    def readPickle(self):
        with open('data.pickle', 'rb') as f:
            return pickle.load(f)

if __name__ == '__main__':
    ab = Ab()
    dataReader = DataReader()
    ab2 = dataReader.readPickle()
    print('ab', ab)
    print('ab2', ab2)

    if isinstance(ab, Ab):
        print('isinstance ab')

    if isinstance(ab2, Ab):
        print('isinstance ab2')

For an example of transferring from the network, I will give an example of transferring data through a file
. First, m2.py imports a class from a module, searilizes and saves (such as a network packet) into a file data.pickle
Next, m1.py is executed, reads data from a file and tries to determine whether they belong class. The output of the script is:

ab <__main__.Ab object at 0x03482E68>
ab2 <m1.Ab object at 0x0349C160>
isinstance ab

That is, it is clear here that ab2 has m1 written in front of the dot and, as I understand it, the second condition does not work because of this, if isinstance(ab2, Ab)and how in this case to check class membership?

And in the end I want to determine what type of data came from the network using OOP

Answer 1

Don't use pickle from external sources at all: this format allows arbitrary code to be executed on deserialization. Well, if you really want to, take out Ab in the general package.