__getattribute__ and methods proxying

[Giampaolo Rodolà]

2010/6/12 David Zaslavsky <diazona at ellipsix.net>:
> Hi,
>
> The problem is that when you make this call:
>> proc.cmdline()
> there are really two steps involved. First you are accessing proc.cmdline,
> then you are calling it. You could think of it as this:
>  func = proc.cmdline
>  func()
> __getattribute__ is able to modify how the first step works, but not the
> second. And it is the second step where the OSError gets raised.
>
> You could get around this by returning a wrapper function from
> __getattribute__, something like this I think:
>
>     def __getattribute__(self, name):
>         f = object.__getattribute__(self, name)
>         # here you should really check whether it's a function
>         def wrapper(self, *args, **kwargs)
>             print "here 1!"
>             try:
>                 f(*args, **kwargs)
>             except OSError, err:
>                 print "here 2!"
>                 if err.errno == errno.ESRCH:
>                     raise NoSuchProcess
>                 if err.errno == errno.EPERM:
>                     raise AccessDenied
>        return wrapper
>
> That way "func" gets set to the wrapper function, which will handle your
> exception as you want.
>
> :) David
> --
> http://mail.python.org/mailman/listinfo/python-list
>

Clear, thanks.
Isn't there a prettier/common way to do this?
A __methodcall__(self, method_obj) special method or something? Has
something like that ever been proposed for inclusion?



--- Giampaolo
http://code.google.com/p/pyftpdlib
http://code.google.com/p/psutil