装饰器应用练习

1.qqweiboweixin登陆认证

# 带参数的装饰器：（相当于开关）为了给装饰器传参

def login(s):
    def outer(func):
        def inner(*args, **kwargs):
            if s == 'QQ':
                print('login by QQ')
                ret = func(*args, **kwargs)
            elif s == 'wx':
                print('login by wx')
                ret = func(*args, **kwargs)
            elif s == 'wb':
                print('login by wb')
                ret = func(*args, **kwargs)
            else:
                ret = func(*args, **kwargs)
            return ret
        return inner
    return outer

@login('QQ')   # login('QQ') = outer -> @outer -> f1 = outer(f1)
def f1():
    print('in f1
')

@login('wx')   # login('wx') = outer -> @outer -> f2 = outer(f2)
def f2():
    print('in f2
')

@login('wb')   # login('wb') = outer -> @outer -> f3 = outer(f3)
def f3():
    print('in f3
')

f1()
f2()
f3()

2.编写装饰器，为多个函数加上认证功能(用户的账号密码来自文件)，要求登陆成功后，后续的函数都无需再输入用户名及密码

# __author__ = "wyb"
# date: 2018/4/22
#
# 编写装饰器，为多个函数加上认证功能(用户的账号密码来自文件)，
# 要求登陆成功后，后续的函数都无需再输入用户名及密码
import time
flag = True             # flag为True未登录


# 打开文件将文件中的用户名和密码存入字典中
use_pwd = {}
with open("account.txt", "r") as f:
    for line in f:
        u, p = line.split(',')
        use_pwd[u] = p.strip()
    # print(use_pwd)


def login(login_type):
    def wrapper(func):
        def inner(*args, **kwargs):
            global flag
            if flag:
                username = input("username: ")
                password = input("password: ")
                if use_pwd.get(username, None) == password:
                    print("Welcome, %s, and login by %s " % (username, login_type))
                    func(*args, **kwargs)
                    flag = False
                else:
                    print("用户名或密码错误!")
            else:
                func(*args, **kwargs)
        return inner
    return wrapper


@login('QQ')
def index():
    time.sleep(1)
    print("Welcome to index")


@login('WX')
def home():
    time.sleep(2)
    print("Welcome to home")


@login('WB')
def page():
    time.sleep(3)
    print("Welcome to page")


page()
index()
home()