Noob Q: subclassing or wrapping file class
Steven D'Aprano
steven at REMOVE.THIS.cybersource.com.au
Wed Sep 16 18:09:59 EDT 2009
On Wed, 16 Sep 2009 21:56:09 +0000, kj wrote:
...
> I thought at first that I could achieve this by overriding __getattr__:
>
> def __getattr__(self, attribute):
> return self.fh.__getattr__(attribute)
>
> But to my surprise this did not work too well. For example, if I use a
> GzipFile object as the argument to MyFile, the iterator of the resulting
> object works as expected, but if I attempt to access its closed
> attribute I get the error
>
> AttributeError: GzipFile instance has no attribute '__getattr__'
>
> And it doesn't have __getattribute__ either. (And here I'd been
> thinking that __getattr__ and __getattribute__ were pretty much
> universal... Clearly not!)
>
> Is there a standard idiom that I'm missing for doing this sort of thing?
Instead of:
x.__getattr__('name')
write this:
getattr(x, 'name')
Also, do a search for "automatic delegation python", or just look at Alex
Martelli's cookbook recipe:
http://code.activestate.com/recipes/52295/
--
Steven
More information about the Python-list
mailing list