The other day I needed to decorate a method with a decorator class that knows about the owner of the method meaning the instance. This works as expected with function decorators:
def some_decorator(func):
def decorator(self, *args, **kwargs):
print 'instance %s of class %s is now decorated whee!' % (
self, self.__class__
)
return func(*args, **kwargs)
return decorator
class SomeClass(object):
@some_decorator
def dostuff(self, foo, bar):
print 'do %s, %s' % (foo, bar)
If you need/want to use a class based decorator you have to do this:
class SomeDecorator(object):
def __init__(self, func):
self.func = func
def __call__(self, *args, **kwargs):
print 'instance %s of class %s this is now decorated whee!' % (
self.obj, self.cls
)
return self.func.__call__(*args, **kwargs)
def __get__(self, instance, owner):
self.cls = owner
self.obj = instance
return self.__call__
class SomeClass(object):
@SomeDecorator
def dostuff(self, foo, bar):
print 'do %s, %s' % (foo, bar)
Thanks to Ozgur who's post about the topic pointed me in the right direction.