在运行时修饰类方法

Question

我想装饰一个类方法，但是在运行时(我的意思是在方法之前不需要用@notation来指定装饰符)

请参阅标准方法装饰器的示例：

def method_decorator(func):
    def decorated(self, *args, **kwargs):
        print('decorator:', args, kwargs)
        return func(self,*args, **kwargs)
    return decorated

class Standard():
    @ method_decorator
    def decorated(self, *args, **kwargs):
        print('decorated: ', args, kwargs)

s = Standard()
s.decorated(1,2)

结果：

decorator: (1, 2) {}
decorated:  (1, 2) {}

所以我在运行时尝试了不同的方法：

class RunTime():
    def set_decorator_1(self, decorator):
        self.decorated = decorator(self.decorated)
    def set_decorator_2(self, decorator):
        RunTime.decorated = decorator(RunTime.decorated)
    def set_decorator_3(self, decorator):
        self.decorated = decorator(RunTime.decorated)
    def set_decorator_4(self, decorator):
        setattr(self, 'decorated', decorator(RunTime.decorated))
    def set_decorator_5(self, decorator):
        setattr(self, 'decorated', decorator(self.decorated))
    def decorated(self, *args, **kwargs):
        print('decorated: ', args, kwargs)

r = RunTime()
r.set_decorator_*(method_decorator)
r.decorated(1,2)

以下是产出：

1. 装潢器没有正确装饰：

decorator: (2,) {}
decorated:  (1, 2) {}

instance.

• Bad

• 按预期工作，但是当调用set_decorator时，所有RunTime实例也会被修饰，这是我想要避免的，因为我只想装饰单个set_decorator RunTime

的方法。

decorator: (2,) {}
decorated:  (2,) {}

1. 同3
2. 同1

我还尝试了另一个装饰器，它可以很好地工作(使用set_decorator_1)，但不允许我在其中访问self：

def method_decorator_runtime(func):
    def decorated( *args, **kwargs):
        print('decorator: ', args, kwargs)
        return func( *args, **kwargs)
    return decorated

是否有人知道如何在运行时对方法进行适当的修饰，并能够在装饰器中访问自己？

Answer 1

我为您的问题找到的最接近的解决方案是使用带有参数的装饰器，在这里可以传递具有其方法修饰的对象的实例。

def method_decorator(self_eventually):
    def decorator(func):
        def decorated(*args, **kwargs):
            print('decorator:', repr(self_eventually), args, kwargs)
            return func(*args, **kwargs)
        return decorated
    return decorator

class RunTime():

    def set_decorator(self, decorator):
        self.decorated = decorator(self)(self.decorated)

    def decorated(self, *args, **kwargs):
        print('decorated:', repr(self), args, kwargs)

r = RunTime()
r.set_decorator(method_decorator)
r.decorated(1, 2)