Using copyreg to pickle unpicklable oblects

[kerbingamer376]

On Monday, September 19, 2016 at 5:48:35 PM UTC+1, Peter Otten wrote:
> kerbingamer376 wrote:
> 
> > Hi,
> 
> [No need to start a new thread for this]
> 
> > I have an object (pygame.mixer.Sound) and, to convert it to a picklable
> > format, I can run:
> > 
> > sound_object.get_raw()
> > 
> > and to turn that back into an object, I can run:
> > 
> > sound_object = pygame.mixer.Sound(raw_data)
> > 
> > Is it possible to use copyreg or something similar so it's done
> > automatically when I pickle pygame.mixer.Sound() objects?
> 
> Have a look at the example from the documentation:
> 
> >>> import copyreg, copy, pickle
> >>> class C(object):
> ...     def __init__(self, a):
> ...         self.a = a
> ...
> >>> def pickle_c(c):
> ...     print("pickling a C instance...")
> ...     return C, (c.a,)
> ...
> >>> copyreg.pickle(C, pickle_c)
> 
> 
> Translating that gives (untested)
> 
> import copyreg # copy_reg in Python 2
> import pygame.mixer
> 
> def pickle_sound(sound):
>     return pygame.mixer.Sound, (sound.get_raw(),)
> 
> copyreg.pickle(pygame.mixer.Sound, pickle_sound)
> 
> Does that work?

I get:

_pickle.PicklingError: Can't pickle <class 'Sound'>: attribute lookup Sound on builtins failed