python中的無參裝飾器和有參裝飾器
阿新 • • 發佈：2018-02-25
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python中的無參裝飾器和有參裝飾器
作者：尹正傑
版權聲明：原創作品，謝絕轉載！否則將追究法律責任。
裝飾器特點：
1>.開放封閉原則，即對擴展是開放的，對修改時封閉的；
2>.裝飾器本質可以是任意可調用的對象，被裝飾的對象也可以是任意可調用對象；
3>.裝飾器的功能是在不修改被裝飾器對象源代碼以及被裝飾器對象的調用方式的前提下為其擴展新功能；
4>.裝飾器本質是函數，（即裝飾其他函數）就是為其他函數添加附加功能。
一.典型裝飾器案例
1 #！/usr/bin/env python 2 #_*_coding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie/tag/python%E8%87%AA%E5%8A%A8%E5%8C%96%E8%BF%90%E7%BB%B4%E4%B9%8B%E8%B7%AF/ 5 #EMAIL:[email protected] 6 7 #裝飾器的語法:在被裝飾對象的正上方的單獨一行，@裝飾器名字 8 import time 9 import random 10 11 def RunTime(TheCaller): #定義裝飾器 12 def MyCaller(): 13 start_time = time.time() 14 TheCaller() 15 stop_time=time.time() 16 print(‘run time is %s‘ %(stop_time-start_time)) 17 return MyCaller 18 19 #被裝飾函數 20 @RunTime #等效於index=RunTime(index) 21 def index(): 22 time.sleep(random.randrange(2,4)) #可以在1-3秒鐘(不包括4秒喲)隨機睡眠指定範圍的時長。 23 print(‘welecome to INDEX page‘) 24 25 @RunTime #home=RunTime(home) 26 def home(): 27 time.sleep(random.randrange(1,2)) 28 print(‘welecome to HOME page‘) 29 30 index() #MyCaller() 31 home() 32 33 34 35 36 #以上代碼執行結果如下： 37 welecome to INDEX page 38 run time is 2.0000088214874268 39 welecome to HOME page 40 run time is 1.0006351470947266
二.多個裝飾器案例展示
1 #！/usr/bin/env python 2 #_*_coding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie/tag/python%E8%87%AA%E5%8A%A8%E5%8C%96%E8%BF%90%E7%BB%B4%E4%B9%8B%E8%B7%AF/ 5 #EMAIL:[email protected] 6 7 #裝飾器的語法:在被裝飾對象的正上方的單獨一行，@裝飾器名字 8 import time 9 import random 10 from functools import wraps 11 12 def RunTime(TheCaller): #定義裝飾器+ 13 @wraps(TheCaller) #可以讓用戶查看幫助信息的時候查看其自己的源代碼定義的幫助信息。 14 def MyCaller(*args,**kwargs): 15 ‘‘‘ 16 Runtime‘s help information 17 ‘‘‘ 18 start_time = time.time() 19 res = TheCaller(*args,**kwargs) 20 stop_time=time.time() 21 print(‘run time is %s‘ %(stop_time-start_time)) 22 return res 23 24 return MyCaller 25 26 def NewAddAuth(TheCaller): 27 def Auth(*args,**kwargs): 28 name=input(‘username: ‘) 29 password=input(‘password: ‘) 30 if name == ‘yinzhengjie‘ and password == ‘123‘: 31 print(‘login successful‘) 32 res = TheCaller(*args,**kwargs) 33 return res 34 else: 35 print(‘login error‘) 36 return Auth 37 38 #被裝飾函數 39 # @NewAddAuth 40 @RunTime #等效於index=RunTime(index)，裝飾器的執行順序是自下而上。 41 def Index(): 42 ‘‘‘ 43 Index‘s help information 44 ‘‘‘ 45 time.sleep(random.randrange(2,4)) #可以在1-3秒鐘(不包括4秒喲)隨機睡眠指定範圍的時長。 46 print(‘welecome to INDEX page‘) 47 return "yinzhengjie" 48 49 @RunTime #home=RunTime(home) 50 def Home(name): 51 ‘‘‘ 52 Home‘s help information 53 ‘‘‘ 54 time.sleep(random.randrange(1,2)) 55 print(‘welecome to %s HOME page‘%(name)) 56 return 666 57 58 res1 = Index() #MyCaller() 59 res2 = Home("尹正傑") 60 print("Index return :%s"%(res1)) 61 print("Home return :%s"%(res2)) 62 # print(help(Index)) 63 # print(Index().__doc__) 64 65 66 67 68 #以上代碼執行結果如下： 69 welecome to INDEX page 70 run time is 3.000018835067749 71 welecome to 尹正傑 HOME page 72 run time is 1.0001890659332275 73 Index return :yinzhengjie 74 Home return :666
三.有參裝飾器
1 #！/usr/bin/env python 2 #_*_coding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie/tag/python%E8%87%AA%E5%8A%A8%E5%8C%96%E8%BF%90%E7%BB%B4%E4%B9%8B%E8%B7%AF/ 5 #EMAIL:[email protected] 6 7 ‘‘‘ 8 編寫裝飾器，為多個函數加上認證的功能（用戶的賬號密碼來源於文件），要求登陸成功一次，後續的函數都無需再驗證。 9 ‘‘‘ 10 11 12 # user_dic = { 13 # ‘yinzhengjie‘:‘123‘, 14 # ‘Golang‘:"666", 15 # ‘Python‘:"888", 16 # } 17 # 18 # with open("user.db","w",encoding="utf-8")as f: 19 # f.write(str(user_dic)) 20 21 22 23 24 db_path = "user.db" 25 26 login_dic ={ 27 ‘user‘:None, 28 "status":False, 29 } 30 31 def Decorator(AuthType="file"): 32 def auth(func): 33 def wrapper(*args, **kwargs): 34 if AuthType == "file": 35 if login_dic[‘user‘] and login_dic[‘status‘]: 36 res = func(*args, **kwargs) 37 return res 38 username = input("username:") 39 password = input("password:") 40 with open(db_path, "r", encoding="utf-8")as f: 41 user_dic = eval(f.read()) 42 if username in user_dic and password == user_dic[username]: 43 print(‘login successful‘) 44 login_dic[‘user‘] = username 45 login_dic[‘status‘] = True 46 res = func(*args, **kwargs) 47 return res 48 else: 49 print(‘login error‘) 50 elif AuthType == "ldap": 51 print("LDAP認證方式") 52 elif AuthType == "MySQL": 53 print("MySQL認證方式") 54 else: 55 print("其他認證方式") 56 return wrapper 57 return auth 58 59 @Decorator() 60 def Index(): 61 print("Welcome to Index!") 62 63 @Decorator(AuthType="MySQL") 64 def home(name): 65 print("Welecome %s to home page!"%name) 66 67 Index() 68 home("尹正傑") 69 70 71 72 73 #以上代碼執行結果如下： 74 username:yinzhengjie 75 password:123 76 login successful 77 Welcome to Index! 78 MySQL認證方式
四.小試牛刀
1.編寫裝飾器，為多個函數加上認證的功能（用戶的賬號密碼來源於文件），要求登陸成功一次，後續的函數都無需再驗證。
1 #！/usr/bin/env python 2 #_*_coding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie/tag/python%E8%87%AA%E5%8A%A8%E5%8C%96%E8%BF%90%E7%BB%B4%E4%B9%8B%E8%B7%AF/ 5 #EMAIL:[email protected] 6 7 8 # user_dic = { 9 # ‘yinzhengjie‘:‘123‘, 10 # ‘Golang‘:"666", 11 # ‘Python‘:"888", 12 # } 13 # 14 # with open("user.db","w",encoding="utf-8")as f: 15 # f.write(str(user_dic)) 16 17 18 19 20 db_path = "user.db" 21 22 login_dic ={ 23 ‘user‘:None, 24 "status":False, 25 } 26 27 def auth(func): 28 def wrapper(*args,**kwargs): 29 if login_dic[‘user‘] and login_dic[‘status‘]: 30 res = func(*args, **kwargs) 31 return res 32 username = input("username:") 33 password = input("password:") 34 with open(db_path, "r", encoding="utf-8")as f: 35 user_dic = eval(f.read()) 36 if username in user_dic and password == user_dic[username]: 37 print(‘login successful‘) 38 login_dic[‘user‘] = username 39 login_dic[‘status‘] = True 40 res = func(*args,**kwargs) 41 return res 42 else: 43 print(‘login error‘) 44 return wrapper 45 46 @auth 47 def Index(): 48 print("Welcome to Index!") 49 50 @auth 51 def home(name): 52 print("Welecome %s to home page!"%name) 53 54 Index() 55 home("尹正傑") 56 57 58 59 60 以上代碼執行結果如下： 61 username:yinzhengjie 62 password:123 63 login successful 64 Welcome to Index! 65 Welecome 尹正傑 to home page!
2.編寫下載網頁內容的函數，要求功能是：用戶傳入一個URL，函數返回下載頁面的內容。
1 #！/usr/bin/env python 2 #_*_coding:utf-8_*_ 3 #@author :yinzhengjie 4 #blog:http://www.cnblogs.com/yinzhengjie/tag/python%E8%87%AA%E5%8A%A8%E5%8C%96%E8%BF%90%E7%BB%B4%E4%B9%8B%E8%B7%AF/ 5 #EMAIL:[email protected] 6 7 8 from urllib.request import urlopen 9 import os 10 11 cache_path=r‘cache.txt‘ 12 def make_cache(func): 13 def wrapper(*args,**kwargs): 14 if os.path.getsize(cache_path):#說明有緩存 15 print(‘\033[45m=========有緩存=========\033[0m‘) 16 with open(cache_path,‘rb‘) as f: 17 res=f.read() 18 19 else: 20 res=func(*args,**kwargs) #下載 21 with open(cache_path,‘wb‘) as f: #制作緩存 22 f.write(res) 23 24 return res 25 26 return wrapper 27 28 @make_cache 29 def get(url): 30 return urlopen(url).read() 31 32 33 print(‘============first============‘) 34 print(get(‘http://www.cnblogs.com/yinzhengjie‘)) 35 print(‘============second===========‘) 36 print(get(‘http://www.cnblogs.com/yinzhengjie‘)) 37 print(‘============third============‘) 38 print(get(‘http://www.cnblogs.com/yinzhengjie‘))
python中的無參裝飾器和有參裝飾器