How do I link a file to the document?

Question

I have Python 3.5 code that logs a user.

It creates a user and logs them in.

After I kill the program and re-run it, it does not remember the details of the user it created.

Please share some of the code you have attempted, you are much more likely to get help here if you show you have done some work towards the problem first. — cfreear, Nov 11 '16 at 12:04

score 0 · Answer 1 · answered Nov 11 '16 at 12:20

I was doing a similar project earlier this week and this is what i cane up with!

import csv

def displayMenu():
    status = input("Are you a registered user? y/n? ")  
    if status == "y":
        login()
    elif status == "n":
        newUser()

def login():

    with open('users.txt') as csvfile:
        reader = csv.DictReader(csvfile)
        database = []
        for row in reader:
            database.append(dict(username=row['username'],
                                 password=row['password'],
                                 function=row['function']))

loggedin = False
while not loggedin:
    Username = input('Fill in your username: ')
    Password = input('Fill in your password: ')
    for row in database:
        Username_File = row['username']
        Password_File = row['password']
        Function_File = row['function']
        if (Username_File == Username and
            Password_File == Password and
                Function_File == 'user'):
            loggedin = True
            print('Succesfully logged in as ' + Username)
        elif (Username_File == Username and
              Password_File == Password and
                Function_File == 'admin'):
            loggedin = True
            print('Succesfully logged in as the admin.')
        if loggedin is not True:
            print ('Failed to sign in, wrong username or password.')

def newUser():
    signUp = False
    while not signUp:
        NewUsername = input("Create login name: ")
        NewUsername = str(NewUsername)
        with open('users.txt', 'r') as UserData:
                reader = csv.reader(UserData, delimiter=',')
        if (NewUsername) in open('users.txt').read():
            print ('Login name already exist!')

        else:
            NewPassword = input("Create password: ")
            NewPassword = str(NewPassword)
            with open('users.txt', 'a') as f:
                writer = csv.writer(f)
                UserPassFunction = (NewUsername,NewPassword,'user')
                writer.writerows([UserPassFunction])
            print("User created!")
            signUp = True






# ---- Main ---- #

displayMenu()

score 0 · Answer 2 · edited May 23 '17 at 12:13

You can read and write data to a file to store the users login details, where Logindetails.txt is a .txt file stored in the same location as your program. Windows notepad uses .txt files.

import linecache
with open("LoginDetails.txt", "r") as po:
    LoginDetails = linecache.getline('LoginDetails.txt', int(LineNumber)).strip()

"r" will open the file in read only mode. "r+" will allow you to read and write to the file.

def replace_line(file_name, line_num, text):
    lines = open(file_name, 'r').readlines()
    lines[line_num] = text
    with open(file_name, 'w') as out:
        out.writelines(lines)

P.S I did not create this, original post here Editing specific line in text file in python

I would recommend using a SQL database for login details though, if you wish to use SQL I would recommend using the sqlite3 library/module

Also, your program is probally not able to 'remember my details' because you probally store the details as a variable which is changed by a user input, which is stored in RAM. This data is wiped once the program is closed, so if it is changed via a user input, the input will have to be re changed every time you close the program.

You can also scan the file for a string, such as a username. Search for string in txt file Python

How do I link a file to the document?

2 Answers2