关于字典：Python Pickled Passwords


Python Pickled Passwords

这是我使用pickle的python密码系统。我知道这很糟糕，但这是我第一次吃泡菜。

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import pickle
import os

userlist = {'user1':'userpass1', 'user2':'userpass2'}

users = open ("users.pkl", 'wb')

pickle.dump (userlist, users)

username = input ("Enter your username:")
password = input ("Enter your password:")

if (username in userlist) and (password == userlist[username]):
    print ("Access Granted")
else:
   newaccount = input ("User not found. Shall I create a new account?")
    if newaccount =="yes":
       username = input ("Please enter your username:")
       password = input ("Please enter yout password:")
       userlist.update({username:password})
       pickle.dump (userlist, users)
       users.close()

我的问题是，每当我要添加一个新帐户时，使用此部分：

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 newaccount = input ("User not found. Shall I create a new account?")
    if newaccount =="yes":
        username = input ("Please enter your username:")
        password = input ("Please enter yout password:")
        userlist.update({username:password})
        pickle.dump (userlist, users)
        users.close()

它似乎添加了它(看起来像是在使用记事本的pickle文件中)，但是，我重新启动了python文件，它没有看到它。

我认为这与这部分有关：

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userlist = {'user1':'userpass1', 'user2':'userpass2'}

users = open ("users.pkl", 'wb')

pickle.dump (userlist, users)

感谢您的帮助！D

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每次使用w运行程序时都会覆盖：

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users = open ("users.pkl", 'wb')

如果您想要获取以前的pickled项，那么您需要查看文件是否已经存在，以及pickle.load是否要获取以前的pickled项，然后在代码末尾查看dump。

如下所示：

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from tempfile import NamedTemporaryFile

try:
    # see if we have run  this before
    with  open ("users.pkl", 'rb') as users:
       users_dict = pickle.load(users)
except IOError:
    # if not set to defualt
    users_dict = {'user1':'userpass1', 'user2':'userpass2'}


username = input ("Enter your username:")
password = input ("Enter your password:")

if users_dict.get(username) == password: # unless a password can be None we can use get
    print ("Access Granted")
else:
    newaccount = input("User not found. Shall I create a new account?")
    if newaccount =="yes":
       username = input("Please enter your username:")
       password = input ("Please enter yout password:")
       users_dict[username] = password # just use key = value

with NamedTemporaryFile("wb",dir=os.path.dirname("users.pkl"),delete=False) as f: # in case we get exception use temp file
    pickle.dump (users_dict, f)
os.replace(f.name,"users.pkl") # update original
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