Store object using Python pickle, and load it into different namespace

Question

I\'d like to pass object state between two Python programs (one is my own code running standalone, one is a Pyramid view), and different namespaces. Somewhat related questio

Answer 1

Solution 1

On pickle.load, the module __main__ needs to have a function or class called MyClass. This does not need to be the original class with the original source code. You can put other methods in it. It should work.

class MyClass(object):
    pass

with open("my_c.pik", "rb") as f :
    c = pickle.load(f)

Solution 2

Use the copyreg module which is used to register constructors and pickle functions to pickle specific objects. This is the example given by the module for a complex number:

def pickle_complex(c):
    return complex, (c.real, c.imag)

copyreg.pickle(complex, pickle_complex, complex)

Solution 3

Override the persistent_id method of the Pickler and Unpickler. pickler.persistent_id(obj) shall return an identifier that can be resolved by unpickler.persistent_id(id) to the object.