关于python：编写一个类装饰器，将装饰器应用于所有方法

Writing a class decorator that applies a decorator to all methods

我正在尝试编写一个类修饰器，它将修饰器应用于所有类的方法：

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import inspect

def decorate_func(func):
def wrapper(*args, **kwargs):
print"before"
ret = func(*args, **kwargs)
print"after"
return ret
for attr in"__module__","__name__","__doc__":
setattr(wrapper, attr, getattr(func, attr))
return wrapper

def decorate_class(cls):
for name, meth in inspect.getmembers(cls, inspect.ismethod):
setattr(cls, name, decorate_func(meth))
return cls

@decorate_class
class MyClass(object):

def __init__(self):
self.a = 10
print"__init__"

def foo(self):
print self.a

@staticmethod
def baz():
print"baz"

@classmethod
def bar(cls):
print"bar"

obj = MyClass()
obj.foo()
obj.baz()
MyClass.baz()
obj.bar()
MyClass.bar()

它几乎可以工作，但@classmethod需要特殊处理：

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$ python test.py
before
__init__
after
before
10
after
baz
baz
before
Traceback (most recent call last):
File"test.py", line 44, in <module>
obj.bar()
File"test.py", line 7, in wrapper
ret = func(*args, **kwargs)
TypeError: bar() takes exactly 1 argument (2 given)

号

有没有办法很好地处理这个问题？我检查了@classmethod装饰方法，但我看不出有什么不同于其他"类型"方法的地方。

更新

这里是记录的完整解决方案(使用描述符很好地处理@staticmethods和@classmethods，以及AIX检测@classmethods与正常方法的技巧)：

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import inspect

class DecoratedMethod(object):

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

def __get__(self, obj, cls=None):
def wrapper(*args, **kwargs):
print"before"
ret = self.func(obj, *args, **kwargs)
print"after"
return ret
for attr in"__module__","__name__","__doc__":
setattr(wrapper, attr, getattr(self.func, attr))
return wrapper

class DecoratedClassMethod(object):

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

def __get__(self, obj, cls=None):
def wrapper(*args, **kwargs):
print"before"
ret = self.func(*args, **kwargs)
print"after"
return ret
for attr in"__module__","__name__","__doc__":
setattr(wrapper, attr, getattr(self.func, attr))
return wrapper

def decorate_class(cls):
for name, meth in inspect.getmembers(cls):
if inspect.ismethod(meth):
if inspect.isclass(meth.im_self):
# meth is a classmethod
setattr(cls, name, DecoratedClassMethod(meth))
else:
# meth is a regular method
setattr(cls, name, DecoratedMethod(meth))
elif inspect.isfunction(meth):
# meth is a staticmethod
setattr(cls, name, DecoratedClassMethod(meth))
return cls

@decorate_class
class MyClass(object):

def __init__(self):
self.a = 10
print"__init__"

def foo(self):
print self.a

@staticmethod
def baz():
print"baz"

@classmethod
def bar(cls):
print"bar"

obj = MyClass()
obj.foo()
obj.baz()
MyClass.baz()
obj.bar()
MyClass.bar()