functools模块与装饰器

原始装饰器

def function_wrapper(wrapped):
    def _wrapper(*args, **kwargs):
        return wrapped(*args, **kwargs)
    return _wrapper 

@function_wrapper
def function():
    pass

但是抱歉，有点小问题

>>> print(function.__name__)
_wrapper

这时候我门使用functools.wrap， 它会帮我门自动填充__name__, __doc__，还有python3中__qualname__和__annotations__

import functools 

def function_wrapper(wrapped):
    @functools.wraps(wrapped)
    def _wrapper(*args, **kwargs):
        return wrapped(*args, **kwargs)
    return _wrapper 

@function_wrapper
def function():
    pass 

>>> print(function.__name__)
function

类装饰器

class function_wrapper(object):
    def __init__(self, wrapped):
        self.wrapped = wrapped
    def __call__(self, *args, **kwargs):
        return self.wrapped(*args, **kwargs)

@function_wrapper
def function():
    pass

会出现同样的问题，这时候我门需要用functools.update_wrap

import functools 

class function_wrapper(object):
    def __init__(self, wrapped):
        self.wrapped = wrapped
        functools.update_wrapper(self, wrapped)
    def __call__(self, *args, **kwargs):
        return self.wrapped(*args, **kwargs)