装饰器在调用之前注册功能

Question

I would like to decorate bar and baz to register them with Container and collect the callback in Foo . Is this possible given python decorators?

class Foo(object):
    results = []
    def __init__(self, app):
        self.app = app
        self.registerAll()

    def registerAll(self):
        self.results.append(self.app.myRegister(self.baz))
        self.results.append(self.app.myRegister(self.bar))

    def baz(self):
        print("baz")

    def bar(self):
        print("bar")

class Container(object):
    funcs = []

    def start(self):
        self.f = Foo(self)

    def myRegister(self, f):
        self.funcs.append(f)
        print("myRegister")
        def callback(res):
            print('cb')
        return callback

x = Container()
x.start()

Answer 1

Your question looks suspiciously like an XY Problem , since it's very unclear what you ultimately hope to accomplish by registering the functions (which are actually class methods). (Also see What is the XY problem? ) Nevertheless, here's one way to do what you want — assuming I understand what you have so far in your question.

I made Container.myRegister() a classmethod since it only references an attribute of the class it is in. I also defined the Container class before the Foo class so the former could be referenced by the decorator. In addition I removed the registerAll() method, since it's no longer needed (however that means the class attribute results is now not referenced anywhere, so maybe it should be removed, too...).

class Container(object):
    funcs = []

    def start(self):
        self.f = Foo(self)

    @classmethod
    def myRegister(cls, f):
        cls.funcs.append(f)
        print("myRegister")
        def callback(res):
            print('cb')
        return callback

def decorate(cls):
    def decorator(method):
        cls.myRegister(method)
        return method
    return decorator

class Foo(object):
    results = []

    def __init__(self, app):
        self.app = app

    @decorate(Container)
    def baz(self):
        print("baz")

    @decorate(Container)
    def bar(self):
        print("bar")

x = Container()
x.start()