Python User Registration

Question

I am trying to make a working user registration program. When asked for the username, the system will look to see if the text entered has already been stored. If the username has already been stored, it will ask for the password for that user. However, if the username has not been stored, it will ask for a password. When these are entered, the script will then appendix onto a .txt of a .py file to make an new account. After the account has been made, the script can then read the .txt or .py file for the login information. My current login code:

loop = "true"
while(loop == "true"):
    username = input("Enter Username: ")
    password = input("Enter Password: ")
    h = input ("Do You Need Help [Y/N]: ")
    if(h == "Y" or h == "y" or h == "yes" or h == "Yes"):
    print ("Enter username and password to login. If you do not have an account yet, enter 'Guest' as the username and press enter when it asks for the password.")
    elif(h == "N" or h == "n" or h == "no" or h == "No"):
        print (" >> ")
    if(username == "Hello World" and password == "Hello World" or username == "Test User" and password == "Test User" or username == "Guest"):
        print ("Logged in Successfully as " + username)
        if(username == "Guest"):
            print ("Account Status: Online | Guest User")
        if not (username == "Guest"):
            print ("Account Status: Online | Standard User")

How do you make a database that python can read from for the username and password? Also, how do you make it so that python can appendix to the database to add more usernames and passwords?

This is Python v3.3.0 Mac OSX 10.8

Thank you in advance!

Answer 1

Try using the pickle module:

>>> import pickle
>>> myusername = "Hello"
>>> mypassword = "World"
>>> login = [myusername, mypassword]
>>> pickle.dump(login, open("%s.p" % login[0], "wb")) #Saves credentials in Hello.p, because Hello is the username
>>> #Exit

Now to get it back

>>> import pickle
>>> try:
...    password = pickle.load(open("Hello.p", "rb"))[1]
...    username = pickle.load(open("Hello.p", "rb"))[0]
... except IndexError: #Sees if the password is not there
...    print("There is no information for those credentials")
...
>>> password
'mypassword'
>>> username
'myusername'

If there is no password or username, it prints There is no information for those credentials... Hope this helps!

AND JUST A TIP: don't bother going through if(h == 'n'..., just do a h.lower().startswith("n") == True. .lower() makes everything lowercase, and str.startswith("n") checks if str starts with the letter n.