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Python - How to store a username/password from input

I was wondering how to store a username and password from input, and put it into a sort of database that is on the same python file. I would want the username and password to only be saved for however long the file is open, and don't require any long term storage of the data, thanks in advance!

This pretty simple stuff so I'll just give you the short answer, but you should probably do some more research on this in the future, as well provide the code you've written.
credentials = {}
def create():
username = input('Username: ')
password = input('Password: ')
credentials[username] = password
def authenticate():
username = input('Username: ')
password = input('Password: ')
return credentials[username] == password
Use create() to create users and authenticate() to log users in

why is this pickle implementation not working(ie what am I missing)

In this code i am trying to use pickle to permanently store the values for the new username created when the user creates a new account but come up with logical errors. and the values in the dictionary still stay the same.(I know i am clearly missing something obvious here but I actually don't know what that is)
# defining variables
create_username = 0
create_password = 0
password = 0
username = 0
# importing pickle
import pickle
# creates a users dictionary
users = {
'Joe': 'juk725',
'Mat': 'axr3',
'Th3_j0k3r': 'bl4z3',
'ag4r-j3lly': 'Micr0b3'
}
# sign up (creating new account)
while username not in users and username != 'signup':
username = input("enter username(type signup to create an account): ")
# add new user to dictionary
if username == "signup" or username == "Signup":
create_username = input("enter a new username: ")
create_password = input("enter a new password (Your password cannot be the same as your username !!!!!!!): ")
if create_password in users:
create_password = input("password taken re-enter: ")
# then adds the new username to the users dictionary
if username == 'signup':
users[create_username] = create_password
pickle.dump(users, open('pickle_file_name.p', 'wb'))
else:
if username in users:
password = input("enter password: ")
if password in users:
print("access granted")
if username not in users:
username = input("enter username: ")
if password not in users:
print("access denied")

You're never opening the pickled file, and so your code reuses the same dictionary input repeatedly.
You should just create a script to first create the pickle file, then replace the definition of users that you have with pickle.load method call
# importing pickle
import pickle
# creates a users dictionary
with open('pickle_file_name.p', 'rb') as f:
users = pickle.load(f)
# sign up
If you want a readable file, I'd suggest json module rather than pickle. If you want to more easily query the users, then sqlite3
Also not really relevant here, but password hashing would be a good idea to learn for any such project with accounts, rather than storing data in plaintext

Python - Help needed with file reading

I am trying to create a simple login system. What I'm doing is storing the login data in a text file called 'accounts.txt'
Now, when user tires to login, it first checks if the username given by the user is in the 'accounts.txt'. If it exists, then it asks for the password and then checks if password matches with the password in 'accounts.txt'
fr = open('accounts.txt', 'r')
while True:
username = input('Enter your username: ') # Ask for their username
if username in fr.read(): # Check if username exists
password = input('Enter password: ') # Ask for password if username exists
if username+password in fr.read():
print('Welcome ' + username)
break
else:
print('Wrong password')
Note, the password save in accounts.txt is in the format of usernamepassword so if username is jack and password is gate, the actual password in the txt file will be jackgate, hence im using username+password to check if password is correct.
The problem occuring is if the user enters correct username, then program moves ahead properly but even if the password entered is right, it still displays 'Wrong password' .When the second time user enters username, it even shows error for wrong username. I tried to play with the code for a long time but couldn't come up with a solution. I guess it has something to do with fr.read(). Can I use that 'fr' object only once?

Let me suggest some improvements with my answer to your question. I would read the accounts file in its entirety so you have an in-memory structure. If you do this as a dictionary in the form accounts[USER] -> PASS you can easily check for any account as per the code below.
Regarding my suggestions (they do not exactly only answer your questions, but IMHO the topic of writing login code should be treated with care):
I strongly recommend not to store passwords in plain text, regardless of application importance, always use hashes.
Do not store just the password hash, always use salting.
Do not tell the person trying to log in, if the username or the password was wrong, always just say "that's not the right combination", thus making it harder to break in.
Please find information about hashing functions in Python here: https://docs.python.org/3/library/hashlib.html#randomized-hashing
This site has a good introduction on salting ans securing passwords: https://crackstation.net/hashing-security.htm
Do you users a favor and treat the username as no case-sensitive. That is a totally valid approach, but it annoys me every time I have to use such a site (just like email addr are not case-sensitive)
As I am a total layman regarding password security, maybe one of the other Stackoverflow users can jump in with a comment and expand on this topic.
Anyway, here is my answer for your question on how to check for a login. I created a function check_account() that returns True or False, depending on wether the supplied credentials were correct or not.
import hashlib
import os
import binascii
def check_account(usr, pwd):
# read the accounts file, a simple CSV where
# username, salt value and password hash are
# stored in three columns separated by a pipe char
accounts = {}
fr = open('/users/armin/temp/test.csv', 'r')
for line in [x.strip().split("|") for x in fr.readlines()]:
accounts[line[0].lower()] = (line[1], line[2])
fr.close()
# now go looking if we do have the user account
# in the dictionary
if usr in accounts:
credentials = accounts[usr]
# credentials is a list with salt at index 0
# and pwd hash at index 1
# generate the hash form the functions parameters
# and compare with our account
h = hashlib.blake2b(salt=binascii.unhexlify(credentials[0]))
h.update(pwd.encode('utf-8'))
if credentials[1] == h.hexdigest():
return True
else:
return False
else:
return False
def main():
while True:
username = input('Enter your username: ') # Ask for their username
password = input('Enter password: ') # Ask for password if username exists
if check_account(username.lower(), password):
print("Welcome, {0}".format(username))
else:
print('Username or password unknown')
if __name__ == '__main__':
main()
To create the data for a user account, use may this code.
def create():
username = input('Enter your username: ').lower() # Ask for their username
password = input('Enter password: ') # Ask for password if username exists
salt = binascii.hexlify(os.urandom(hashlib.blake2b.SALT_SIZE))
print("SALT value:", salt)
h = hashlib.blake2b(salt=binascii.unhexlify(salt))
h.update(password.encode('utf-8'))
print("Pwd hash:", h.hexdigest())

You can use startswith and endswith:
fr = [i.strip('\n') for i in open('accounts.txt')]
while True:
username = input()
if any(i.startswith(username) for i in fr):
password = input('Enter password: ')
if any(username+password == i for i in fr):
print("welcome")
break
else:
print("wrong password")

I would do
if password in fr.read():
instead of
if username+password in fr.read():
This is because for it to get to the if password in fr.read loop it first has to pass the if username in fr.read loop. However, the only problem I find with this is that if they enter a correct username but enter the wrong password for that username but correct password for another username it will still pass.
That is why I think you should use a dictionary not a text file.
For example, if the usernames allowed is username and username1 and the password is username and username1, then in a different .py file, you can say.
username_password={'username':'username','username1':'username1'}
that makes a dictionary that has the username and passwords.
let's say you name that file stuff.py. Then in the second file that has to be in the same directory, you can do
from stuff import * #imports all values from stuff.py
while True:
username = input('Enter your username: ') #gets username
if username_password.has_key(username):
password = input('Enter password: ')
if password== username_password[username]:
print('Welcome '+username)
break
else:
print('Wrong password')
break
else:
print('Wrong username')
I still don't get why you have a while loop, but if you want it, it is fine. Also, I added an else loop just in case the username is wrong.

Retrieve a value from MongoDB and set a string to it in Python(Pymongo)

I am trying to retrieve a value from MongoDB and set a string to it in Python with MongoDB. Here is my user registration function:
def registerAccount():
registerUsername = input('Please input a username to be registered into our database.')
registerPassword = input('Please input a password to be entered into our database.')
passwordHash = sha256_crypt.hash(registerPassword)
regDetails = {
"username": registerUsername,
"passwordhash": passwordHash
}
db = client.pinnacle
users = db.users
users.insert(regDetails)
and here is my login function:
def login():
db = client.pinnacle
users = db.users
pwHash = users.find_one({"passwordhash"})
print(str(pwHash))
loginUsername = input('Please input username to be signed in.')
loginPassword = input('Please input password to be signed in.')
# pprint.pprint(users.find_one({"username": "1"}))
# example = users.find_one({"username": "1"})
pbkdf2_sha256.verify(loginPassword, pwHash)
Basically, I need to search the database for the username, and get the string right after the username which is passwordHash. Then I will set pwHash to that string which will be checked with PassLib. Help is appreciated. Thanks!
Also if anyone is interested you can see my full code here.

this happens whenever i select to login, even after not typing in username or password
The error is caused by this line below:
pwHash = users.find_one({"passwordhash"})
Where you should specify a filter of key/value pair, instead it's only specifying a key. You should remove the line above (and the print line right after it). See also pymongo find_one() method for more info.
Also, in the same function login(), you have a typo for key username.
user = users.find_one({"userName": loginUsername})
Note that it should be lowercase username to be consistent with how you're storing them elsewhere in the code.
Lastly, you should replace
pbkdf2_sha256.verify(loginPassword, user['passwordhash'])
with below method, as this is how you encrypt it in the registerAccount()
sha256_crypt.verify(loginPassword, user['passwordhash'])
Please consider adding error checks throughout your code. i.e. if users.find_one() returns None do XYZ.

Python: matching user names w/ password ; prompted for password if incorrect ;

I am trying to create a login.
I am not sure how to create/import a library of usernames and passwords; I am researching to find an answer at the moment but asked either way.
Match usernames with passwords (partially solved; need to add multiple usernames with matching passwords).
How to create a loop if password is incorrect? If incorrect password is entered the user needs to be prompted again to enter the password.
How to limit loop to certain number of attempts for password.
Below is what I have tried:
def check_password(user, password):
""" Return True if the user/pass combo is valid and False otherwise. """
# Code to lookup users and passwords goes here. Since the question
# was only about how to do a while loop, we have hardcoded usernames
# and passwords.
return user == "pi" and password == "123"
def login():
""" Prompt for username and password, repeatedly until it works.
Return True only if successful.
"""
try:
while True:
username = raw_input('username:')
password = raw_input('password:')
if check_password(username, password):
break
else:
print "Please try again"
print "Access granted"
return True
except:
return False
For testing: login().
This fixed lack of loop prompting if wrong password due to using return instead of print; and if instead of while.
def login():
#create login that knows all available user names and match to password ; if password is incorect returns try again and propmts for password again#
username = raw_input('username:')
if username !='pi':
#here is where I would need to import library of users and only accept those usernames; needs to be like 'pi' or 'bob' or 'tim'etc.
print'user not found'
username = raw_input('username')
password = raw_input('password:')
#how to match password with user? store in library ?
while password != '123':
print 'please try again' # You have to change the 'return' to 'print' here
password = raw_input('password')
return 'access granted'
#basically need to create loop saying 'try again' and prompting for password again; maybe smarter to ask limited number of
#times before returning 'you have reached limit of attempts#
if password == '123':
#again matching of passwords and users is required somehow
return 'access granted'
>>> login()
username:wronguser
user not found
usernamepi
password:wrongpass
please try again
password123
'access granted'
>>>
First attempt before updating thanks to Merigrim:
def login():
# Create login that knows all available user names and match to password;
# if password is incorect returns try again and propmts for password again#
username = raw_input('username:')
if username !='pi':
# Here is where I would need to import library of users and only
# accept those usernames; needs to be like 'pi' or 'bob' or 'tim'etc.
return 'user not found'
password = raw_input('password:')
# How to match password with user? store in library?
if password != '123':
return 'please try again'
password = raw_input('password:')
if password != '123':
return 'please try again'
# Basically need to create loop saying 'try again' and prompting
# for password again; maybe smarter to ask limited number of
# times before returning 'you have reached limit of attempts
elif password == '123':
# Again matching of passwords and users is required somehow
return 'access granted'
Here is how it currently works:
>>> login()
username:pi
password:123
'access granted'
>>> login()
username:pi
password:wrongpass
'please try again'
I need to create loop to prompt again for password.

What you want is the while statement.
Instead of nesting if-statements like this:
if password != '123':
return 'please try again'
password = raw_input('password:')
if password != '123':
return 'please try again'
elif password == '123':
return 'access granted'
You can do this:
while password != '123':
print 'please try again' # You have to change the 'return' to 'print' here
password = raw_input('password:')
return 'access granted'
This will continue prompting the user for a password until the right password is entered. If you want to become more familiar with the while statement, I suggest checking out some tutorials, like this one.
Please note that if you return something the function will exit there, so the user will never be prompted for a password. In the code above I changed the return to a print statement instead.

Here's another solution with the user name and password factored out, and an exception handler in case someone tries to abort the input.
Also, FYI it is best to take the user and password together so as not to let crackers know what is and is not a valid username.
def check_password(user, password):
""" Return True if the user/pass combo is valid and False otherwise. """
# Code to lookup users and passwords goes here. Since the question
# was only about how to do a while loop, we have hardcoded usernames
# and passwords.
return user == "pi" and password == "123"
def login():
""" Prompt for username and password, repeatedly until it works.
Return True only if successful.
"""
try:
while True:
username = raw_input('username:')
password = raw_input('password:')
if check_password(username, password):
break
else:
print "Please try again"
print "Access granted"
return True
except:
return False
# For testing
login()