[Django]-Decorating Instance Methods in Python

by

7👍

✅

def decorate_method(f):
  def wrapper(self, name, value, attrs):
    self.attrs = attrs
    return f(self, name, value, attrs)
  return wrapper

def decorate_class(c):
  for n in dir(c):
    f = getattr(c, n)
    if hasattr(f, 'im_func'):
      setattr(c, n, decorate_method(f.im_func))

You’ll probably need some other test to skip methods with a different signature, but, apart from that, decorate_class(whatever) should do what you want on any given class whatever.

👤Alex Martelli

3👍

The “classic” way is to subclass. This way you don’t have to mess with other peoples classes.

class someclass(object):
    def render(self, name, value, attrs):
        print hasattr(self, 'attrs')

class my_render(object):
    def render(self, name, value, attrs):
        self.attrs = attrs # kind of decorating the function here
        return super(my_render, self).render(name, value, attrs)

class my_class(my_render, someclass): 
    pass    

someclass().render(1,2,3) # -> False
my_class().render(1,2,3) # -> True

The reason for MI is that all classes can inherit from my_render. I like the mixin concept 😉

class my_otherclass(my_render, someotherclass): pass
class my_thirdclass(my_render, thirdclass): pass

# or less explicit
classlist = [ someclass, someotherclass ]
newclasses = [ type('my_'+cls.__name__, (my_render,cls), {}) for cls in classlist ]
👤Jochen Ritzel

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