9mTSWUKt

1import hashlib
2import json
3import os
4import sqlite3
5from getpass import getpass
6
7path = "C:/Users/16102/Documents/Advanced Beginner Projects/login/Part 2_SQL"
8os.chdir(path)
9
10# connect to sqlite3
11conn = sqlite3.connect(os.path.join(path, "users_db.db"))
12c = conn.cursor()
13
14
15def setup_db():   
16    # creates table in database
17    users_db = '''
18        CREATE TABLE IF NOT EXISTS users (
19        username TEXT PRIMARY KEY,
20        password TEXT
21        );
22        '''
23    c.execute(users_db)
24
25
26def ask_recreate():
27    # count users and ask to recreate db
28    count_users = '''SELECT * FROM users;'''
29    c.execute(count_users)
30    num_users = len(c.fetchall())
31    
32    print("Your users table currently holds %d users." % num_users)
33    
34    del_table = input("Would you like to delete the current table and start over? (y/n): ")
35    if del_table.lower().strip() in ['y', 'yes']:
36        del_stmt = '''DROP TABLE users;'''
37        c.execute(del_stmt)
38        
39    setup_db()
40
41
42def show_db():
43    # displays all registered users
44    c.execute('''SELECT * FROM users;''')
45    rows = c.fetchall()
46    
47    for row in rows:
48        print(row)   
49
50
51def sha_encrypt(pw):
52    # sha256 hashing
53    encode_hash = hashlib.sha256(pw.encode())
54    hash_pw = encode_hash.hexdigest() 
55    
56    return hash_pw
57
58
59def register():   
60    username = input("Please enter a username: ").lower()
61    
62    # ensure passwords match      
63    invalid = True
64    while invalid:
65        pw = getpass("Please enter a password: ")
66        pw2 = getpass("Please confirm your password: ")
67        
68        if pw == pw2:
69            invalid = False
70        elif pw != pw2:
71            print("Passwords are not the same")
72
73    # hash password
74    hash_pw = sha_encrypt(pw)
75            
76    # save to sqlite3 database. Return error if username taken
77    try:
78        insert_user = "INSERT INTO users VALUES (?, ?);"
79        c.execute(insert_user, (username, hash_pw))
80    except sqlite3.IntegrityError:
81        print("ERROR: Username already exists")
82        register()
83    
84
85def is_valid_credentials():
86    # get username and password and check if they match db users
87    username = input("Please enter a username: ")
88    pw = getpass("Please enter a password: ")
89    hash_pw = sha_encrypt(pw)
90    
91    # execute sqlite3 command. Returns None if doesn't exist
92    select_users = '''SELECT * FROM users WHERE username=? AND password=?;'''
93    c.execute(select_users, (username, hash_pw))
94    if c.fetchone() is not None:
95        print("Welcome")
96    else:
97        print("Login failed. Username or password is incorrect.")
98
99    
100def main():
101    setup_db()
102    ask_recreate()
103        
104    # ask to register or login
105    undecided = True
106    while undecided:
107        log_type = input("Would you like to register or login? Type register or login: ")
108        if log_type.strip().lower() == "register":
109            register()
110            break
111        elif log_type.strip().lower() == "login":
112            is_valid_credentials()
113            break
114        else:
115            print("Please type a valid response")
116
117    # closing connection and commiting changes
118    conn.commit()
119    conn.close()
120    
121
122if __name__ == "__main__":
123    main()