Decorator for both class methods and functions

Question

I have a decorator

def deco(func):
    def inner(params):
        #< DO STUFF WITH func >
    return inner

And a base class

class GenericClass:
    def __init__(self,value):
        self.value = value
    def method(self,params):
        print 'NOT IMPLEMENTED YET'
    def other_method(self):
        print 'GOOD TO GO'

I would like to be able to decorate the "method" method on classes which are child of GenericClass, for exemple to check input/output or handle exceptions (the method "method" will be overrided)

what I want to do is something like...

class ChildClass(GenericClass):
    @deco
    def method(self,params):
        #< NEW METHOD >

I am not an expert python developper and all the doc at that level is quite confusing (i.e. metaclasses, subtleties in decorators, __call__ method etc etc) and I didn't found the solution on SO.

Answer 1

Got it. You are basically asking how to write a decorator which can be applied to both functions and methods. It's possible:

def deco(func):
    def inner(*args):
        print('DECORATED: args={}'.format(args))
        func(*args)
    return inner

class Class:
    @deco
    def method(self, param): print('PARAM is {}'.format(param))

@deco
def func(a, b, c): print('{} {} {}'.format(a, b, c))

Class().method('X')

func(1, 2, 3)

OUTPUT:

DECORATED: args=(<__main__.Class instance at 0x7f740c6297a0>, 'X')
PARAM is X
DECORATED: args=(1, 2, 3)
1 2 3

P.S.

One year later I found one useful post (which was asked 8 years ago) here: Using the same decorator (with arguments) with functions and methods. The approach described there will be useful if you are care of actual parameters of the decorated function.