15-python-decorators

Posted 2021-02-20 daspig

# 装饰器：装饰、装修
# 开放封闭原则：对代码的扩展开放；对源码的修改是封闭的。
# 装饰器：在不改变原函数代码以及调用方式的前提下为其增加新的功能。

import time
# print(time.time())  # 格林威治时间

# round 1
# 如果测试别人的代码必须重新赋值。
# def index():
#     time.sleep(2)
#     print(‘欢迎登录youtube‘)
#
# start_time = time.time()
# index()
# end_time = time.time()
# print(end_time-start_time)
#
# def index2():
#     time.sleep(2)
#     print(‘欢迎登录youtube‘)
#
# start_time = time.time()
# index2()
# end_time = time.time()
# print(end_time-start_time)

# round 2
# 利用函数解决代码重复问题
# index源码没变，给原函数添加了一个新的功能测试原函数的执行效率的功能，但是改变了原函数的调用方式
# def index():
#     time.sleep(2)
#     print(‘欢迎登录youtube‘)
#
# def index2():
#     time.sleep(2)
#     print(‘欢迎登录youtube2‘)
#
# def timer(func):
#     start_time = time.time()
#     func()
#     end_time = time.time()
#     print(end_time-start_time)

# timer(index2)

# round 3
# 不改变原函数的调用方式
# def index():
#     time.sleep(2)
#     print(‘欢迎登录youtube‘)
#
# def index2():
#     time.sleep(2)
#     print(‘欢迎登录youtube2‘)
#
# def timer(func):
#     def inner():
#         start_time = time.time()
#         func()
#         end_time = time.time()
#         print(end_time-start_time)
#     return inner
# index = timer(index)
# index2 = timer(index2)
# index()
# index2()

# round 4
# python做了一个优化，提出了一个语法糖的概念
# def timer(func):
#     def inner():
#         start_time = time.time()
#         func()
#         end_time = time.time()
#         print(end_time-start_time)
#     return inner
#
# @timer
# def index():
#     time.sleep(2)
#     print(‘欢迎登录youtube‘)
# @timer
#
# def index2():
#     time.sleep(2)
#     print(‘欢迎登录youtube2‘)
#
# index()
# index2()

# round 5
# 被装饰函数带返回值
# ret获取inner中的func的返回值
# def timer(func):
#     def inner():
#         start_time = time.time()
#         ret = func()
#         end_time = time.time()
#         print(end_time-start_time)
#         return ret
#     return inner
#
# @timer
# def index():
#     time.sleep(2)
#     print(‘欢迎登录youtube‘)
#     return 666
#
# ret = index()
# print(ret)

# round 6
# 被装饰函数带返回值
# ret获取inner中的func的返回值
# def timer(func):
#     def inner(n):
#         start_time = time.time()
#         ret = func(n)
#         end_time = time.time()
#         print(end_time-start_time)
#         return ret
#     return inner
#
# @timer
# def index(a):
#     time.sleep(2)
#     print(f‘欢迎{a}登录youtube‘)
#     return 666
#
# ret = index(‘hello‘)
# print(ret)

# round 7
# 标准版装饰器
# 格式：
# def wrapper():
#     def inner(f):
#         ret = f(*args,**kwargs)
#         return ret
#     return inner

# def timer(func):
#     def inner(*args, **kwargs):
#         start_time = time.time()
#         ret = func(*args, **kwargs)
#         end_time = time.time()
#         print(end_time-start_time)
#         return ret
#     return inner
#
# @timer
# def index(*args, **kwargs):
#     time.sleep(2)
#     print(f‘欢迎{args}登录youtube‘)
#     return 666
#
# ret = index(‘hello‘)
# print(ret)

# 装饰器的应用：登录认证
# status_dict = {
#     ‘name‘: None,
#     ‘status‘: False,
# }
# 
# def login():
#     print(‘login‘)
# 
# def auth(f):
#     def inner(*args, **kwargs):
#         if status_dict[‘status‘]:
#             ret = f(*args, **kwargs)
#             return ret
#         else:
#             username = input(‘name: ‘).strip()
#             password = input(‘pass: ‘).strip()
#             if username == ‘dfg‘ and password == ‘123‘:
#                 print(‘login success‘)
#                 status_dict[‘name‘] = username
#                 status_dict[‘status‘] = True
#                 ret = f(*args, **kwargs)
#                 return ret
#             else:
#                 print(‘login fail‘)
#     return inner
# 
# def register():
#     print(‘register‘)
# 
# @auth
# def article():
#     print(‘article‘)
# @auth
# def comment():
#     print(‘comment‘)
# @auth
# def dariy():
#     print(‘dariy‘)
# 
# article()
# comment()
# dariy()