emmm......就当练习了系列13

一：编写函数，（函数执行的时间用time.sleep(n)模拟）

import time
def index(a, b):
    num = a + b
    time.sleep(6)
    print(num)
    return num

二：编写装饰器，为函数加上统计时间的功能

def timer(func):
    def wrapper(*args,**kwargs):
        start_time=time.time()
        res=func(*args,**kwargs)
        stop_time=time.time()
        print('run time is %s' %(stop_time-start_time))
        return res
    return wrapper

index = timer(index)
index(1,2)





'''
输出结果(结合一+二题)

3
run time is 6.0002734661102295

'''

三：编写装饰器，为函数加上认证的功能

def login(func):
    def wrapper(*args,**kwargs):
        user_name = input('请输入用户名：')
        user_pwd = input('请输入密码：')
        with open('db.txt',mode='r',encoding='utf-8') as f:
            login = {}
            for line in f:
                name, pwd = line.strip().split(':')
                login[name] = user_pwd
                if user_name in login and user_pwd == login[name]:
                    print('登录成功!')
                elif user_name not in login:
                    print('用户名不存在!')
                else:
                    print('密码错误!')
    return wrapper
index = login(index)
index(1,2)

四：编写装饰器，为多个函数加上认证的功能（用户的账号密码来源于文件），要求登录成功一次，后续的函数都无需再输入用户名和密码
注意：从文件中读出字符串形式的字典，可以用eval('{"name":"egon","password":"123"}')转成字典格式

db = 'db.txt'
login_status = {'user': None, 'status': False}
def auth(auth_type='file'):
    def auth2(func):
        def wrapper(*args, **kwargs):
            if login_status['user'] and login_status['status']:
                return func(*args, **kwargs)
            if auth_type == 'file':
                with open(db, encoding='utf-8') as f:
                    dic = eval(f.read())
                name = input('username: ').strip()
                password = input('password: ').strip()
                if name in dic and password == dic[name]:
                    login_status['user'] = name
                    login_status['status'] = True
                    res = func(*args, **kwargs)
                    return res
                else:
                    print('username or password error')
            elif auth_type == 'sql':
                pass
            else:
                pass
        return wrapper
    return auth2

@auth()
def index():
    print('index')

@auth(auth_type='file')
def home(name):
    print('welcome %s to home' % name)


index()
home('egon')

五：编写装饰器，为多个函数加上认证功能，要求登录成功一次，在超时时间内无需重复登录，超过了超时时间，则必须重新登录

import time,random
user = {'user': None, 'login_time': None, 'timeout': 0.000003, }

def timer(func):
    def wrapper(*args, **kwargs):
        s1 = time.time()
        res = func(*args, **kwargs)
        s2=time.time()
        print('%s' % (s2-s1))
        return res
    return wrapper


def auth(func):
    def wrapper(*args, **kwargs):
        if user['user']:
            timeout = time.time()-user['login_time']
            if timeout < user['timeout']:
                return func(*args, **kwargs)
        name = input('name>>: ').strip()
        password = input('password>>: ').strip()
        if name == 'egon' and password == '123':
            user['user'] = name
            user['login_time'] = time.time()
            res = func(*args, **kwargs)
            return res
    return wrapper

@auth
def index():
    time.sleep(random.randrange(3))
    print('welcome to index')

@auth
def home(name):
    time.sleep(random.randrange(3))
    print('welcome %s to home ' % name)

index()
home('egon')

六：选做题
# 思考题（选做），叠加多个装饰器，加载顺序与运行顺序，可以将上述实现的装饰器叠加起来自己验证一下
# @deco1 # index=deco1(deco2.wrapper的内存地址)
# @deco2 # deco2.wrapper的内存地址=deco2(deco3.wrapper的内存地址)
# @deco3 # deco3.wrapper的内存地址=deco3(index)
# def index():
# pass

@timer
@auth
def index(x, y):
    num = x + y
    time.sleep(5)
    print(num)
    return num

index(1,2)
index(2,3)
index(3,4)