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 =
>
> 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
>>> shutil.yadda
Peter
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