1、編寫裝飾器,為多個函式加上認證的功能(使用者的賬號密碼來源於檔案)要求登入成功一次,後續的函式都無需再輸入使用者名稱和密碼
FLAG = False def login(func): def inner(*args,**kwargs): global FLAG if FLAG: ret = func(*args,**kwargs) return ret else: #登入程式 username = input(`請輸入使用者名稱:`) password = input(`請輸入密碼:`) if username == `ysg` and password == "275": FLAG = True ret = func(*args,**kwargs) return ret else: print("登入失敗") return inner @login def shoplist_add(): print("向購物車中新增物品") @login def shoplist_del(): print("向購物車中新增物品") shoplist_add() shoplist_del()
FLAG = False def login(f): def inner(*args,**kwargs): #判斷是否以成功登入 global FLAG if FLAG: ret = f(*args,**kwargs) return else: #登入驗證 use = input(`>>>`) pwd = input(`>>>`) lis=[] with open(`E:/py/info.txt`,`r`,encoding=`utf-8`)as info: for i in info: lis.append(i) if use == lis[0].strip() and pwd == lis[1].strip(): print(`登陸成功`) FLAG = True ret = f(*args,**kwargs) return ret else: print(`登入失敗`) return inner @login def shoping(): print(`在購物`) @login def money(): print(`在支付`) shoping() money()
2、編寫裝飾器,為多個函式加上記錄呼叫功能,要求每次呼叫函式都將被呼叫的函式名稱寫入檔案
def log(func): def inner(*arge,**kwargs): with open(`E:/py/log/log.txt`,`a`,encoding=`utf-8`) as f: f.write(func.__name__ + ` `) ret = func(*arge,**kwargs) print("") return ret return inner @log def shoplist_add(): print("購買了一件商品") @log def shoplist_del(): print("刪除了一件商品") shoplist_add() shoplist_del() shoplist_add() shoplist_del() shoplist_add() shoplist_del()
進階練習:
1.編寫下載網頁內容的函式,要求功能是:使用者傳入一個url,函式返回下載頁面的結果
2.為題目1編寫裝飾器,實現快取網頁內容的功能:
具體:實現下載的頁面存放於檔案中,如果檔案內有值(檔案大小不為0),就優先檔案中讀取網頁內容,否則,就去下載,然後存到檔案中
import os from urllib.request import urlopen def cache(func): def inner(*arge,**kwargs): if os.path.getsize(`E:/py/log/url.txt`): with open ("E:/py/log/url.txt","rb") as f: return f.read() ret = func(*arge,**kwargs) with open(`E:/py/log/url.txt`,`wb`) as f: f.write(ret+b"*****") return ret return inner @cache def get(url): code = urlopen(url).read() return code ret = get(`http://www.baidu.com`) print(ret) ret = get(`http://www.baidu.com`) print(ret)