关于python：装饰方法：AttributeError：’function’对象没有属性’__self__’？

Decorating methods: AttributeError: 'function' object has no attribute 'self'?

我正在与asyncio合作，以确定在特定的相对时间间隔调用调度方法。我决定将调度集中到我编写的类的一个方法中，以减少在我的项目逻辑中出错的可能性。

每次计划方法完成时都应调用此类方法。虽然我在每个方法的末尾添加了loop.call_soon，但我决定给装饰师一个机会。

我编写了一个类修饰器，然后将它应用到我的主类的一些方法中，编写了其余的逻辑和所有这些。但是当尝试在我的项目上测试我的更改时，我得到一个例外：

1	AttributeError: 'function' object has no attribute '__self__'

不知怎么地，修饰我的方法使它成为一个函数。这是我无法理解的，为什么会这样？我怎么能在不放弃装修工人的情况下解决这个问题呢？

下面是我要做的一个最小、完整和可验证的示例：

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import asyncio
from datetime import datetime

class thinkagain:
loop = asyncio.get_event_loop()

def __init__(self, f):
self.fun = f
self.class_ = f.__self__

def __call__(self):
self.fun(*args, **kwords)
# everything in Python is an object
setattr(self.fun,"called", datetime.utcnow())
self.loop.call_later(self.class_.think, 5 * 60)

class DoSomething:
loop = asyncio.get_event_loop()

@thinkagain
def think(self):
attr = getattr(self.dosomething,"called")
if attr:
elapsed = attr - datetime.utcnow()
seconds = elapsed.seconds
else:
seconds = 99999

if seconds >= 20 * 60:
self.loop.call_soon(self.dosomething)

@thinkagain
def dosomething(self):
print("I did something awesome!")

loop = asyncio.get_event_loop()
something = DoSomething()
loop.call_soon(something.think)
loop.run_forever()

号

我得到的例外是：

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Python 3.5.1 (default, Dec 7 2015, 13:41:59)
[GCC 5.2.0] on linux
Type"help","copyright","credits" or"license" for more information.
>>> Traceback (most recent call last):
File"<stdin>", line 1, in <module>
File"/tmp/mcve.py", line 19, in <module>
class DoSomething:
File"/tmp/mcve.py", line 22, in DoSomething
@thinkagain
File"/tmp/mcve.py", line 10, in __init__
self.class_ = f.__self__
AttributeError: 'function' object has no attribute '__self__'
>>>

观看装饰，格雷厄姆邓布利顿高级装饰设计师的方法，探讨各种装饰风味和技术的内部实现。Highly recommended.

Relevant module he introduced at the end：https://github.com/grahamdumpleton/wrapt

我用两个版本修改你的例子。下一个版本的百叶窗属性根据你的要求直接在方法中。

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from datetime import datetime

class thinkagain:

def __init__(self, f):
# Plain function as argument to be decorated
self.func = f

def __get__(self, instance, owner):
self.instance_ = instance
return self.__call__

def __call__(self, *args, **kwargs):
"""Invoked on every call of any decorated method"""

# set attribute directly within bound method
bound_method = getattr(self.instance_, self.func.__name__)
bound_method.__dict__['called'] = datetime.utcnow()

# returning original function with class' instance as self
return self.func(self.instance_, *args, **kwargs)

class DoSomething_A:

@thinkagain
def think(self, *args, **kwargs):
print('
%s' % locals())
print(self.think.called, args, kwargs)
self.dosomething()

@thinkagain
def dosomething(self):
print('%s
' % ('-'*30), locals())
print("%s I did something awful" % self.dosomething.called)

第二个版本的清洁剂和它的皮肤保存在方法中的属性，并直接在程序中分配。

ZZU1

两个都产生同样的愿望：

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>>> something = DoSomething_A().think(1, 2)
{'args': (1, 2), 'kwargs': {}, 'self': <__main__.DoSomething_A object at 0x10209f128>}
2015-12-26 04:13:25.629887 (1, 2) {}
------------------------------
{'self': <__main__.DoSomething_A object at 0x10209f128>}
2015-12-26 04:13:25.647476 I did something awful

和

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>>> something = DoSomething_B().think('arg_a', 'arg_b')
{'args': ('arg_a', 'arg_b'), 'kwargs': {}, 'self': <__main__.DoSomething_B object at 0x10209f208>}
2015-12-26 04:13:25.648039
------------------------------
{'self': <__main__.DoSomething_B object at 0x10209f208>}
2015-12-26 04:13:25.648390

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关于python：装饰方法：AttributeError：’function’对象没有属性’self’？

Decorating methods: AttributeError: 'function' object has no attribute 'self'?

Decorating methods: AttributeError: 'function' object has no attribute '__self__'?

Decorating methods: AttributeError: 'function' object has no attribute 'self'?