如何在Python中为继承的方法添加一个decorator而不复制整个方法？

Question

我有一个类从其父类继承装饰属性。我想再添加一个decorator（@thedecorator1("yyy")），但不重写整个方法和现有的decorator。（装饰工的顺序在某种程度上很重要，装饰工1应始终介于属性.setter以及Decorator2）

在Python3中这是可能的吗？在

from functools import wraps

class thedecorator1:
    def __init__ (self, idx):
        self.idx = idx
    def __call__ (self, func):
        @wraps(func)
        def wrapped(*args, **kwargs):
            print("thedecorator1", self.idx, args)
            return func(*args, **kwargs)
        return wrapped

def thedecorator2(func):
    def _thedecorator2(self, *args, **kwargs):
        print("thedecorator2",args)
        return func(self, *args, **kwargs)
    return _thedecorator2

class SomeClass:
    """That's te base class"""
    _some_property = None

    @property
    @thedecorator2
    def someproperty(self):
        return self._some_property

    @someproperty.setter
    @thedecorator1("xxx")
    @thedecorator2
    def someproperty(self, value):
        self._some_property = value  

class AnotherClass(SomeClass):
    """That's what works, but I need to copy everything everytime"""

    _some_property = None

    @property
    @thedecorator2
    def someproperty(self):
        return self._some_property

    @someproperty.setter
    @thedecorator1("yyy")
    @thedecorator1("xxx")
    @thedecorator2
    def someproperty(self, value):
        self._someproperty = value

class YetAnotherClass(SomeClass):
    """That's what I think I need"""

    dosomethingsmart(target = someproperty, decorator =  thedecorator1("yyy"), after=someproperty.setter)

Answer 1

考虑一下这个程序：

from functools import wraps

def dec1(fn):
    @wraps(fn)
    def wrap(*args, **kw):
        print "dec1", fn.__name__
        return fn(*args, **kw)
    return wrap

def dec2(fn):
    @wraps(fn)
    def wrap(*args, **kw):
        print "dec2", fn.__name__
        return fn(*args, **kw)
    return wrap

class C(object):
    prop = None
    @property
    def foo(self):
        return self.prop

    @foo.setter
    @dec1
    def foo(self, x):
        self.prop = x

class D(C):
    foo = property(
        C.foo.fget,
        dec2(C.foo.fset),
        C.foo.fdel)

print '.'
c=C()
c.foo = 7
print '.'
d = D()
d.foo = 8
print '.'

foo是从C.foo继承get和delete函数的属性，但包装了set函数。在

D的另一个定义是：

^{pr2}$

无论哪种情况，程序的输出都是：

.
dec1 foo
.
dec2 foo
dec1 foo
.

注意，c.foo的赋值调用一个包装器，而对d.foo的赋值同时调用这两个包装器。在