unpickle.py

import sys
import types
import pprint

from pickle import Unpickler

pp = pprint.PrettyPrinter(indent=4)

class GenericClass(object):
    def __new__(cls, *p, **k):
        inst = object.__new__(cls)
        inst.args = ()
        inst.kwargs = {}
        inst.to_dict_called = False
        inst.state = {}
        return inst

    def __init__(self, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs

    def __setstate__(self, state):
        self.state = state

    def to_dict(self):
        if getattr(self, 'to_dict_called', False):
            return {'circle': True}
        self.to_dict_called = True
        d = {'args': self.args, 'kwargs': self.kwargs}
        if not isinstance(self.state, dict):
            return {'state': self.state}
        for k, v in self.state.iteritems():
            if isinstance(v, GenericClass):
                d[k] = v.to_dict()
            else:
                d[k] = v
        return d

    def __repr__(self):
        return str(self.args)

class GenericUnpickler(Unpickler):
    def find_class(self, module, name):
        # Subclasses may override this
        return GenericClass

with open("sample.pickle", "rb") as f :
    myobj = GenericUnpickler(f).load()

pp.pprint(myobj.to_dict())