Add authentication for pre-existing users.

app/db/__init__.py

@@ -47,6 +47,29 @@ class Db(object):
             return None
         return services[0]
 
+    def get_salt_for_user(self, user):
+        salt = self._perform_query_param('select salt from users where name = ?', [user])
+        if len(salt) == 0:
+            return None
+        return salt[0]['salt']
+
+    def check_password_for_user(self, user, password):
+        user = self._perform_query_param('select * from users where name = ? and password = ?', [user, password])
+        if len(user) == 0:
+            return False
+        return True
+
+    def _perform_query_param(self, query, data):
+        cursor = self.db.execute(query, data)
+        names = list(map(lambda x: x[0], cursor.description))
+        result = []
+        for row in cursor.fetchall():
+            row_result = {}
+            for index in range(0, len(names)):
+                row_result[names[index]] = row[index]
+            result.append(row_result)
+        return result
+    
     def _perform_query(self, query):
         cursor = self.db.execute(query)
         names = list(map(lambda x: x[0], cursor.description))