9.4 如何实现属性可修改的函数装饰器?

装饰器改变属性

def test1():
    '''test1...'''
    print('test1')

def test2():
    '''test2...'''
    print('test2')

print (test1.__name__)
print (test1.__doc__)

print (test2.__name__)
print (test2.__doc__)


from functools import wraps

def login_required(view_func):
    # @wraps(view_func)
    def wrapper(*args,**kwargs):
        '''wrapper....'''
        pass
    return wrapper

@login_required
def test1():
    '''test1...'''
    print('test1')

@login_required
def test2():
    '''test2...'''
    print('test2')

print (test1.__name__)
print (test1.__doc__)

print (test2.__name__)
print (test2.__doc__)

输出: 
test1
test1...
test2
test2...
wrapper
wrapper....
wrapper
wrapper...


装饰器修改之后
def login_required(view_func):
    @wraps(view_func)
    def wrapper(*args,**kwargs):
        '''wrapper....'''
        pass
    return wrapper
输出: 
test1
test1...
test2
test2...
test1
test1...
test2
test2...

装饰器的执行顺序

def wrapper1(f1):
    print('in wrapper1')
    def inner1(*args,**kwargs):
        print('in inner1')
        ret = f1(*args,**kwargs)
        print('111')
        return ret
    return inner1

def wrapper2(f2):
    print('in wrapper2')
    def inner2(*args,**kwargs):
        print('in inner2')
        ret = f2(*args,**kwargs)
        print('222')
        return ret
    return inner2

def wrapper3(f3):
    print('in wrapper3')
    def inner3(*args,**kwargs):
        print('in inner3')
        ret = f3(*args,**kwargs)
        print('333')
        return ret
    return inner3

@wrapper1  #3 func = wrapper1(func)即 func = wrapper2(inner2) -->f1 = inner2 -->打印in wrapper1 --> func = inner1
@wrapper2  #2 func = wrapper2(func)即 func = wrapper2(inner3) -->f2 = inner3 --> 打印in wrapper2 --> func = inner2
@wrapper3  #1 func = wrapper3(func) --> f3 = func -->打印in wrapper3 --> func = inner3
def func(): # 先执行离被装饰函数最近的那个装饰器
    print('in func')
func() #4 func = inner1
#5 执行func() 即 执行inner1()-->打印in inner1 --> 执行f1()即执行inner2()-->打印in inner2-->执行f2()即执行inner3()-->打印in inner3-->
#6 -->执行f3()即执行func()-->打印in func-->打印333-->inner3执行完毕，返回到inner2-->打印222-->inner2执行完毕，返回到inner1-->
#7 -->打印111-->inner1执行完毕-->程序执行完毕

# 结果：
# in wrapper3
# in wrapper2
# in wrapper1
# in inner1
# in inner2
# in inner3
# in func
# 333
# 222
# 111

# 装饰器函数在被装饰函数定义好后立即执行。多个装饰器的调用顺序是自下往上的（装饰器装饰函数时的上下顺序）。
# 被装饰函数执行时，装饰器的执行顺序是从上往下的(装饰器装饰函数时的上下顺序，和装饰器函数定义顺序无关)。