Data commit

Task/SQL-based-authentication/Python/sql-based-authentication.py

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+import mysql.connector
+import hashlib
+
+import sys	
+import random	
+
+DB_HOST = "localhost"	
+DB_USER = "devel"
+DB_PASS = "devel"	
+DB_NAME = "test"	
+
+def connect_db():	
+    ''' Try to connect DB and return DB instance, if not, return False '''	
+    try:	
+        return mysql.connector.connect(host=DB_HOST, user=DB_USER, passwd=DB_PASS, db=DB_NAME)	
+    except:	
+        return False	
+
+def create_user(username, passwd):	
+    ''' if user was successfully created, returns its ID; returns None on error '''	
+    db = connect_db()	
+    if not db:	
+        print "Can't connect MySQL!"
+        return None
+
+    cursor = db.cursor()	
+
+    salt = randomValue(16)	 	
+    passwd_md5 = hashlib.md5(salt+passwd).hexdigest()	
+
+    # If username already taken, inform it	
+    try:	
+        cursor.execute("INSERT INTO users (`username`, `pass_salt`, `pass_md5`) VALUES (%s, %s, %s)", (username, salt, passwd_md5))
+        cursor.execute("SELECT userid FROM users WHERE username=%s", (username,) )
+        id = cursor.fetchone()
+        db.commit()
+        cursor.close()
+        db.close()
+        return id[0]	
+    except:	
+        print 'Username was already taken. Please select another'	
+        return None
+
+def authenticate_user(username, passwd):	
+    db = connect_db()	
+    if not db:	
+        print "Can't connect MySQL!"
+        return False
+
+    cursor = db.cursor()	
+
+    cursor.execute("SELECT pass_salt, pass_md5 FROM users WHERE username=%s", (username,))
+
+    row = cursor.fetchone()
+    cursor.close()
+    db.close()
+    if row is None:     # username not found
+        return False
+    salt = row[0]
+    correct_md5 = row[1]
+    tried_md5 = hashlib.md5(salt+passwd).hexdigest()
+    return correct_md5 == tried_md5
+
+def randomValue(length):	
+    ''' Creates random value with given length'''	
+    salt_chars = 'abcdefghijklmnopqrstuvwxyz0123456789'
+
+    return ''.join(random.choice(salt_chars) for x in range(length))
+
+if __name__ == '__main__':	
+    user = randomValue(10)
+    passwd = randomValue(16)	
+
+    new_user_id = create_user(user, passwd)
+    if new_user_id is None:
+        print 'Failed to create user %s' % user
+        sys.exit(1)
+    auth = authenticate_user(user, passwd)	
+    if auth:	
+        print 'User %s authenticated successfully' % user	
+    else:	
+        print 'User %s failed' % user