CODEWITHSUNDEEP
pythonclassdecoratormetaclass
weeb
weeb

Reputation: 1991

python apply decorator to every method in a class without inspect

Slightly modifying the answer from Applying python decorators to methods in a class, it is possible to apply a decorator to every method in a class. Is there any way to do this without the inspect module? I've been trying to accomplish this using metaclasses and modifying __getattribute__ but I keep getting infinite recursion. From How is the __getattribute__ method used?, this can be fixed in normal classes using object.__getattribute__(self, name). Is there anything equivalent for metaclasses?

Upvotes: 0

Views: 1587

Answers (1)

NIlesh Sharma
NIlesh Sharma

Reputation: 5665

Define a meta class and then just apply decorator at the end of class definition.

class Classname:
   def foo(self): pass

for name, fn in inspect.getmembers(Classname):
    if isinstance(fn, types.UnboundMethodType):
        setattr(Classname, name, decorator(fn))

For Python 3 just replace the types.UnboundMethodType with types.FunctionType.

but if you really don;t wanna use inspect than you can do it like this

import types

class DecoMeta(type):
   def __new__(cls, name, bases, attrs):

      for attr_name, attr_value in attrs.iteritems():
         if isinstance(attr_value, types.FunctionType):
            attrs[attr_name] = cls.deco(attr_value)

      return super(DecoMeta, cls).__new__(cls, name, bases, attrs)

   @classmethod
   def deco(cls, func):
      def wrapper(*args, **kwargs):
         print "before",func.func_name
         func(*args, **kwargs)
         print "after",func.func_name
      return wrapper

class MyKlass(object):
   __metaclass__ = DecoMeta

   def func1(self): 
      pass

MyKlass().func1()

Output:

before func1
after func1

Note: it will not decorate staticmethod and classmethod

Upvotes: 3

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