装饰器

装饰器的演变过程：

例.实现一个函数测试电脑的读取速度并花了多少时间

import time
def gettime(arg):
    starttime=time.time()
    arg()
    endtime=time.time()
    print(endtime-starttime)

def go():
    lastnume=0
    for i in range(100000000):
        lastnume+=1
        print(lastnume)
gettime(go)

装饰器本质： 装饰器=函数接口+嵌套函数 

原则：1.不能修改被装饰函数的源码    2.不能修改被装饰函数的调用方式

作用：为其他函数添加附加功能

# 装饰器
def gettime(arg):
    "函数接口用于封装函数"
    def warpper(*args,**kwargs):
        "用于返回实现的功能"
        starttime=time.time()  
        arg()
        endtime=time.time()
        print(endtime-starttime)
    return warpper

@gettime    
def go():
    lastnume=0
    for i in range(100000000):
        lastnume+=1
    print(lastnume)
go()

登陆系统：

user,passwd = 'Temu','etc123123'
def auth(auth_type):
    print("auth func:",auth_type)
    def outer_wrapper(func):
        def wrapper(*args, **kwargs):
            print("wrapper func args:", *args, **kwargs)
            if auth_type == "local":
                username = input("Username:").strip()
                password = input("Password:").strip()
                if user == username and passwd == password:
                    print("33[32;1mUser has passed authentication33[0m")
                    res = func(*args, **kwargs)  # from home
                    print("---after authenticaion ")
                    return res
                else:
                    exit("33[31;1mInvalid username or password33[0m")
            elif auth_type == "admin":
                username = input("Username:").strip()
                password = input("Password:").strip()
                if user == username and passwd == password:
                    print("33[33;1mUser has passed authentication33[0m")
                    res2 = func(*args, **kwargs)  # from home
                    print("---after authenticaion ")
                    return res2
                else:
                    exit("33[31;1mInvalid username or password33[0m")
        return wrapper
    return outer_wrapper

System=["Windows","Unix"]
print(System[0].center(20," "),System[1].center(20," "))

while True:
    User_coice=input("请选择你要登陆的系统：")
    if User_coice == "Windows":
        @auth(auth_type="admin")  #  windows
        def pcwin():
            print("*******Hello,Welcome to Windows page*******")
        pcwin()
        break

    elif User_coice == "Unix":
        @auth(auth_type="local")   # unix
        def home():
            print("Welcome to Home page")
            return "from home"
        print(home())
        break
    else:
        print("没有你要登陆的操作系统，请重新选择...")