Python装饰器保持签名和用户定义的属性

问题描述

我有我的简单装饰 my_decorator ，它装饰 my_func 。

I have my simple decorator my_decorator which decorates the my_func.

def my_decorator(func):
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs)
    wrapper._decorator_name_ = 'my_decorator'
    return wrapper

@my_decorator
def my_func(x):
    print('hello %s'%x)

my_func._decorator_name_
'my_decorator'

到此为止工作，但我看不到该功能的实际签名。

Till here things work, but I can't see the actual signature of the function.

my_func?
Signature: my_func(*args, **kwargs)
Docstring: <no docstring>
File:      ~/<ipython-input-2-e4c91999ef66>
Type:      function

如果我用python的装饰器装饰我的装饰器.decorator ，我可以看到我的函数的签名，但我不能拥有我定义的新属性。

If I decorate my decorator with python's decorator.decorator, I can see the signature of my function but I can't have the new property which I have defined.

import decorator

@decorator.decorator
def my_decorator(func):
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs)
    wrapper._decorator_name_ = 'my_decorator'
    return wrapper

@my_decorator
def my_func(x):
    print('hello %s'%x)

my_func?
Signature: my_func(x)
Docstring: <no docstring>
File:      ~/<ipython-input-8-934f46134434>
Type:      function

my_func._decorator_name_
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-10-7e3ef4ebfc8b> in <module>()
----> 1 my_func._decorator_name_

AttributeError: 'function' object has no attribute '_decorator_name_'

如何在python2.7中同时使用？

How can I have both in python2.7?

推荐答案

对于Python 3，使用：

For Python 3, using functools.wraps in standard library:

from functools import wraps

def my_decorator(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        return func(*args, **kwargs)
    wrapper._decorator_name_ = 'my_decorator'
    return wrapper

@my_decorator
def my_func(x):
    print('hello %s'%x)

print(my_func._decorator_name_)

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