1、什么式装饰器
装饰器本质就是函数，为其他函数添加附加功能
需要把握的原则：
1、不修改被修饰函数的源代码
2、不修改被装饰函数的调用方式
装饰器的知识储备：
装饰器=高阶函数+函数嵌套+闭包
高阶函数的应用举例
1 # -*- coding:utf-8 -*- 2 import time 3 def foo(): 4 time.sleep(1) 5 print("from-foo:您好") 6 def timmer(func): 7 start_time=time.time() 8 func() 9 stop_time = time.time() 10 print("from-time:运行时间%s"%(stop_time-start_time)) 11 return func 12 13 foo=timmer(foo) 14 foo()
函数的嵌套举例
函数里面在定义函数才是嵌套
1 def father(name): 2 print("from father %s" % name) 3 4 def son(): 5 print("from son %s" % name) 6 7 def grandson(): 8 name = "zf1" 9 print("grandfather %s" % name) 10 11 print(locals()) 12 13 14 father("zf")
装饰器的构架
1 # -*- coding:utf-8 -*- 2 3 import time 4 5 6 def timmer(func): 7 def wrapper(): 8 start_time = time.time() 9 func() 10 stop_time = time.time() 11 print("函数运行时间为%.4f" % (stop_time - start_time)) 12 13 return wrapper 14 15 16 def test(): 17 print("函数正在运算中") 18 time.sleep(3) 19 print("函数运算完毕") 20 21 22 test = timmer(test) # @timmer 23 test()
在@timmer====程序中第22行
若test函数有返回值
1 # -*- coding:utf-8 -*- 2 3 import time 4 5 6 def timmer(func): 7 def wrapper(): 8 start_time = time.time() 9 res = func() 10 stop_time = time.time() 11 print("函数运行时间为%.4f" % (stop_time - start_time)) 12 return res 13 14 return wrapper 15 16 17 @timmer 18 def test(): 19 print("函数正在运算中") 20 time.sleep(3) 21 print("函数运算完毕") 22 return "这是test的返回值" 23 24 25 res = test() 26 print(res)
若test函数有参数
# -*- coding:utf-8 -*- import time def timmer(func): def wrapper(*args,**kwargs): start_time = time.time() res = func(*args,**kwargs) stop_time = time.time() print("函数运行时间为%.4f" % (stop_time - start_time)) return res return wrapper @timmer def test(name,age): print("函数正在运算中") time.sleep(1) print("函数运算完毕名字%s，年龄%s"%(name,age)) return "这是test的返回值" res = test("zf",18) print(res)
闭包函数加上认证功能举例
1 # -*- coding:utf-8 -*- 2 3 def test(func): 4 def wrapper(): 5 name=input("name>>>") 6 password=input("password>>>") 7 if name=="zf" and password=="123456": 8 func() 9 else: 10 print("登陆失败") 11 return wrapper 12 13 14 def home(): 15 print("登陆的自己的主页") 16 17 @test 18 def shopping_car(): 19 print("登陆到自己的购物车") 20 21 # home() 22 shopping_car()
闭包函数模拟session
1 # -*- coding:utf-8 -*- 2 user_list=[{"username":"zf","passwd":"123456"},{"username":"zf1","passwd":"1234561"}] 3 4 5 user_stat={"username":None,"login":False} 6 7 8 9 def test(func): 10 def wrapper(): 11 # global passkey 12 if user_stat["username"]==None and user_stat["login"]==False: 13 name = input("name>>>").strip() 14 password = input("password>>>").strip() 15 for user_dict in user_list: 16 if name == user_dict["username"] and password == user_dict["passwd"]: 17 user_stat["username"]=user_dict["username"] 18 user_stat["login"]=True 19 return func() 20 # break 21 else: 22 print("登陆失败") 23 else: 24 return func() 25 26 return wrapper 27 28 29 @test 30 def home(): 31 print("登陆的自己的主页") 32 33 34 @test 35 def shopping_car(): 36 print("登陆到自己的购物车") 37 return "购物成功" 38 39 40 home() 41 res=shopping_car() 42 print(res)
闭包函数带参数的装饰器
1 # -*- coding:utf-8 -*- 2 user_list=[{"username":"zf","passwd":"123456"},{"username":"zf1","passwd":"1234561"}] 3 4 5 user_stat={"username":None,"login":False} 6 7 8 def test1(test_ytpe="file"): 9 def test(func): 10 def wrapper(): 11 print(test_ytpe) 12 # global passkey 13 if user_stat["username"]==None and user_stat["login"]==False: 14 name = input("name>>>").strip() 15 password = input("password>>>").strip() 16 for user_dict in user_list: 17 if name == user_dict["username"] and password == user_dict["passwd"]: 18 user_stat["username"]=user_dict["username"] 19 user_stat["login"]=True 20 return func() 21 # break 22 else: 23 print("登陆失败") 24 else: 25 return func() 26 27 return wrapper 28 return test 29 30 31 @test1() #test=test1() --> @test home=test(home) 32 def home(): 33 print("登陆的自己的主页") 34 35 36 @test1() 37 def shopping_car(): 38 print("登陆到自己的购物车") 39 return "购物成功" 40 41 42 home() 43 res=shopping_car() 44 print(res)