from functools import wraps     # 导入wraps

def wrapper(f):

    @wraps(f)       # wraps的语法糖

    def inner(*args, **kwargs):

        ret = f(*args, **kwargs)

        return ret

    return inner

@wrapper

def f1():

    print("Hello, World!")

    return 'Hi'

res = f1()

print(res)

print(f1.__name__)      # 查看字符串格式的函数名,打印的函数名inner->f1

from functools import wraps

import time

flag = True

def wrapper_out(is_flage):

    def wrapper(func):

        """

        flag为True时函数被装饰器装饰

        flag为FLASE时函数正常被调用

        :param func:

        :return:

        """

        @wraps(func)

        def inner(*args, **kwargs):     # 聚合

            if is_flage:

                start = time.time()

                ret = func(*args, **kwargs)    # 打散

                end = time.time()

                print(end-start)

                return ret

            else:

                ret = func(*args, **kwargs)

                return ret

        return inner

    return wrapper

@wrapper_out(flag)      # @wrapper_out()->@wrapper->f1=wrapper(f1) 调用wrapper_out(flag)函数，return wrapper

def f1():

    time.sleep(1)

    print("Hello, World")

    return 'joker'

ret = f1()

print(ret)

from functools import wraps

def wrapper1(func):     # func->f1

    @wraps(func)

    def inner1(*args, **kwargs):

        print("wrapper1,before")        #

        ret = func(*args, **kwargs)     # 3, f1()

        print("wrapper1,after")         #

        return ret      # ret is f1()的返回值，现在是执行inner1()的返回值

    return inner1

def wrapper2(func):     # func->inner1

    @wraps(func)

    def inner2(*args, **kwargs):

        print("wrapper2,before")        #

        ret = func(*args, **kwargs)     # inner1()

        print("wrapper2,after")         # 5, 执行完inner1()

        return ret      # ret is inner1()的返回值即f1()的返回值，现在是执行inner2()的返回值

    return inner2

@wrapper2       # f1=wrapper2(inner1)

@wrapper1       # f1=wrapper1(f1)->f1=inner1

def f1(a):

    print("Hello")

    return a

"""

f1指向inner2的内存地址，f1()->inner2()，f1()的返回值是inner2()的返回值，也就是f1()函数自身的返回值

"""

ret = f1(2)

print(ret)

"""

结果：

wrapper2,before

wrapper1,before

Hello

wrapper1,after

wrapper2,after

2

"""