2010/5/28 Peter Otten <__pete...@web.de>:
> Giampaolo Rodolà wrote:
>
>> I know, the title doesn't say much, but I had no better ideas. =)
>> I have a class within a serie of redundant methods, which looks like this:
>>
>> class MixedAuthorizer:
>>
>> def __init__(self, *args):
>> # expected a list of class instances
>> self.authorizers = args
>>
>> def get_home(self, user):
>> for auth in self.authorizers:
>> if not auth.has_user(user):
>> continue
>> return auth.get_home(user)
>> return ""
>>
>> def get_password(self, user):
>> for auth in self.authorizers:
>> if not auth.has_user(user):
>> continue
>> return auth.get_password(user)
>> return ""
>>
>> # follows a long list of get_* methods as above
>> ...
>>
>>
>> Considering that I always do the same thing (iterate over a list of
>> objects -> call obj.has_user() -> call obj.get_*()) I would like to
>> know if there's a more compact way to do that.
>> What I basically need is something like __getattr__ but which provides
>> the arguments and eventually the keyword arguments a method has been
>> called with, other than just its name.
>> Actually I'm not even sure whether Python can reach such a level of
>> dynamism but I wanted to give it a try anyway.
>> Is there a way to do such a thing?
>
> Yes, and for the above example it is easier to implement than you think:
>
> class MA(object):
> def __init__(self, authorizers):
> self.authorizers = authorizers
> def __getattr__(self, name):
> def get(self, user):
> for auth in self.authorizers:
> if auth.has_user(user):
> return getattr(auth, name)(user)
> return get.__get__(self)
>
> You can modify it to pass along arbitrary keyword arguments:
>
> class MA(object):
> def __init__(self, authorizers):
> self.authorizers = authorizers
> def __getattr__(self, name):
> def get(self, **kw):
> for auth in self.authorizers:
> if auth.has_user(kw["user"]):
> return getattr(auth, name)(**kw)
> return get.__get__(self)
>
> Peter
> --
> http://mail.python.org/mailman/listinfo/python-list
>
Thanks, this has been helpful.
I managed to write this monster: =)
class MixedAuthorizer(object):
def __init__(self, *authorizers):
self.authorizers = authorizers
def __getattr__(self, name):
def get(self, user, *args, **kwargs):
for auth in self.authorizers:
if auth.has_user(user):
method = getattr(auth, name)
return method(user, *args, **kwargs)
# if we reached this point no user was found
if name == "validate_authentication":
return False
if name.startswith("get"):
return ""
if name.startswith("has"):
return False
return get.__get__(self)
--- Giampaolo
http://code.google.com/p/pyftpdlib
http://code.google.com/p/psutil
--
http://mail.python.org/mailman/listinfo/python-list
