装饰器常用方法

经典调用方法

#!/usr/bin/env python
# -*- coding:utf-8 -*-  
# by wk

import time
import random

'''
一：编写函数，（函数执行的时间是随机的）
'''


def my_random_time(func):
    def wrapper(*args, **kwargs):
        r_time =  random.randint(0,5)
        print('函数将在%s秒后执行' %r_time)
        time.sleep(r_time)
        func(*args, **kwargs)
    return wrapper


@my_random_time
def random_func():
    print('开始运行了')


random_func()

装饰器带参数

#!/usr/bin/env python
# -*- coding:utf-8 -*-  
# by wk

'''
三：编写装饰器，为函数加上认证的功能
'''

def login_func(choose_type='file'):
    def login_func2(func):
        def wrapper(*args, **kwargs):
            username = input('请输入用户名: ')
            password = input('请输入密码: ')
            if choose_type == 'file':
                with open('user.txt','r',encoding='utf-8') as user_r:
                    read_str = user_r.readline()
                    read_dict = eval(read_str)
                    if read_dict['name'] == username and read_dict['password'] == password:
                        func(*args, **kwargs)
                        login_status = 'ok'
                    else:
                        print('登录失败')
                # return login_status
        return wrapper
    return login_func2


@login_func(choose_type='file')
def user_login():
    print('登录成功')


user_login()

带参数方法2

#!/usr/bin/env python
# -*- coding:utf-8 -*-  
# by wk


my_dic={}


def my_func(my_var):
    def wrapper(func):
        my_dic[my_var] = func
    return wrapper


@my_func('select')
def func1():
    print('select')


@my_func('insert')
def func2():
    print('insert')


@my_func('update')
def func3():
    print('update')


@my_func('delete')
def func4():
    print('delete')


print(my_dic)
my_dic['select']()
my_dic['insert']()
my_dic['update']()
my_dic['delete']()

武老师写的装饰器

def Before(request,kargs):
    print('I am before')

def After(request,kargs):
    print('I am After')

def Filter(before_func,after_func):
    def outer(main_func):
        def wrapper(request,kargs):
            before_result = before_func(request,kargs)
            if(before_result != None):
                return before_result
            main_result = main_func(request,kargs)
            if(main_result != None):
                return main_result
            after_result = after_func(request,kargs)
            if(after_result != None):
                return  after_result
        return wrapper
    return outer

@Filter(Before,After)
def index(request,kargs):
    print("I am index")

index('w','k')