David Hirschfield wrote: > I have a need to replace one of the built-in methods of an arbitrary > instance of a module in some python code I'm writing. > > Specifically, I want to replace the __getattribute__() method of the > module I'm handed with my own __getattribute__() method which will do > some special work on the attribute before letting the normal attribute > lookup continue. > > I'm not sure how this would be done. I've looked at all the > documentation on customizing classes and creating instance methods...but > I think I'm missing something about how built-in methods are defined for > built-in types, and where I'd have to replace it. I tried this naive > approach, which doesn't work: > > m = <module instance> > > def __getattribute__(self, attr): > print "modified getattribute:",attr > return object.__getattribute__(self, attr) > > import types > m.__getattribute__ = types.MethodType(__getattribute__,m) > > It seems to create an appropriately named method on the module instance, > but that method isn't called when doing any attribute lookups, so > something's not right. > Any ideas? Is this even possible?
Special methods are looked up in the type, not the instance, and you cannot set attributes of the module type. As a workaround you can write a wrapper class and put that into the sys.modules module cache: >>> class Module(object): ... def __init__(self, module): ... self.__module = module ... def __getattr__(self, name): ... try: ... return getattr(self.__module, name.lower()) ... except AttributeError: ... def dummy(*args): pass ... return dummy ... >>> import shutil >>> import sys >>> sys.modules["shutil"] = Module(shutil) >>> import shutil >>> shutil.MOVE <function move at 0x7f20f9b7d5f0> >>> shutil.yadda <function dummy at 0x7f20f9b7d6e0> Peter -- http://mail.python.org/mailman/listinfo/python-list
