Simple login / registration script.

RegLog.py

from datetime import datetime
from hashlib import *
from bcrypt import hashpw, gensalt

def super_hash_bros(string, salt):
    if salt is None:
        salt = gensalt()
    return (hashpw(string, salt), salt) # not technically how this is used, 
                                        # salt already returned by hashpw

def make_entry(filename, eid, username, password, email, name):
    date = datetime.now()
    password, salt = super_hash_bros(password, None)
    entry = "%i~%i~%s~%s~%s~%s~%s~%s~\n" %\
                    (eid, 0, date, username, password, email, name, salt)
    with open(filename, "a") as database:
        database.writelines(entry)

def get_db(filename):
    usernames, passwords = list(), list()
    
    with open(filename, "r") as database:
        for next_id, line in enumerate(database):
            arr = line.split("~")
            usernames.append(arr[3])
            passwords.append(arr[4] + "~" + arr[7])
            
    database = dict(zip(usernames, passwords))
    
    return database

def register(filename, next_id):
    database = get_db(filename)

    def get_username():
        errors = str()
        
        username = raw_input("Enter your desired username: ").lower()
        
        if not username.isalnum():
            errors += "\tUsername may only contain alphanumeric characters.\n"
        if username in database.keys():
            errors += "\tUsername is taken.\n"
        if len(username) > 16:
            errors += "\tUsername may be no longer than 16 characters.\n"
        
        if errors:
            print "The following errors occurred:\n" + errors
            get_username()
        else:
            return username
    
    def get_password():
        errors = str()
        
        password = raw_input("Enter your desired password: ").lower()
        password_confirm = raw_input("Confirm your password: ").lower()
        
        if not password.isalnum():
            errors += "\tPassword may only contain alphanumeric characters.\n"
        if len(password) > 32:
            errors += "\tPassword may be no longer than 32 characters.\n"
        if password != password_confirm:
            errors += "\tPasswords did not match.\n"
        
        if errors:
            print "The following errors occurred:\n" + errors
            get_password()
        else:
            return password
    
    def get_email():
        errors = str()
        
        email = raw_input("Enter your email: ").lower()
        email_confirm = raw_input("Confirm your email: ").lower()
        
        if not email:
            return str()
        if email.count("@") != 1 or email[-1] == ".":
            errors += "\tInvalid email.\n"
        if email != email_confirm:
            errors += "\tPasswords did not match.\n"
        
        if errors:
            print "The following errors occurred:\n" + errors
            get_email()
        else:
            return email
    
    def get_name():
        errors = str()
        
        name = raw_input("Enter your full name: ").title()
        
        if not name.replace(" ", "").isalnum():
            errors += "\tName is not plausible.\n"
            
        if errors:
            print "The following errors occurred:\n" + errors
            get_name()
        else:
            return email
            
    username = get_username()
    password = get_password()
    email = get_email()
    name = get_name()
    
    make_entry(filename, next_id, username, password, email, name)

    return next_id + 1

def login():
    database = get_db("people.db")
    
    username = raw_input("Username: ")
    password = raw_input("Password: ")
    
    password_parts = database[username].split("~")
    salt = password_parts[1]
    password_in_db = password_parts[0]
    
    
    if username in database.keys() and super_hash_bros(password, salt) == password_in_db:
        print "You got in!"
    else:
        print "Incorrect username / password combination."

def main():
    next_id = 0
    
    while True:
        cmd = raw_input("Do you want to login or register? ").lower()
        
        if cmd in "stop exit quit".split():
            break
        elif cmd == "register":
            next_id = register("people.db", next_id)
        elif cmd == "login":
            login()
        else:
            print "Unknown op: %s" % cmd
        
    print "Goodbye!"

if __name__ == "__main__":
    main()