将包装器应用于函数会阻止它

Question

我正在尝试创建包装器。我的代码适用于简单的示例函数，但是当我将它应用于示例函数时，它停止工作。

我的包装代码：

import functools
import time
from functools import wraps

def profiler(func):
          
    @wraps(func)
    def wrapper(*args, **kwds):
        setattr(func, 'calls', 0)
        t1 = time.monotonic() # what's time at the beginning of run
        func(*args, **kwds)
        func.calls += 1 # add 1 to number of calls
        t2 = time.monotonic() # what's time at the beginning of run
        last_time_taken = t2 - t1
        setattr(wrapper, 'last_time_taken', last_time_taken)
        setattr(wrapper, 'calls', func.calls)
    return wrapper

我很乐意得到任何有助于解决此错误的建议。谢谢！

Answer 1

您的包装器没有 return，这与 returning None 相同。当你调用装饰函数时，你实际上只是运行包装器。

确保包装器 return 是您函数的结果，它会正常工作。

import functools
import time
from functools import wraps

def profiler(func):
          
    @wraps(func)
    def wrapper(*args, **kwds):
        setattr(func, 'calls', 0)
        t1 = time.monotonic() # what's time at the beginning of run
        res = func(*args, **kwds)
        func.calls += 1 # add 1 to number of calls
        t2 = time.monotonic() # what's time at the beginning of run
        last_time_taken = t2 - t1
        setattr(wrapper, 'last_time_taken', last_time_taken)
        setattr(wrapper, 'calls', func.calls)
        return res
    return wrapper

将包装器应用于函数会阻止它

Applying wrapper to a function brakes it

python

decorator

wrapper

python-decorators