tornado_autho_login.py

class LoginHandler(BaseHandler):
    
    def initialize(self):
        database_url = os.environ['BOOKS_DB_CONN']
        self.session = queries.TornadoSession(uri=database_url)

    """
    POST handler for user loggin
    """
    @gen.coroutine   
    def post(self):

        data_json = json.loads(self.request.body)
        try:
            username = data_json.get("username")
            password = data_json.get("password")

            sql = "SELECT username, pwd FROM users WHERE username = %(user)s;"
            results = yield self.session.query(sql, {'user': username})
            data_ret = results.as_dict()
            results.free()

            if pbkdf2_sha256.verify(password, data_ret['pwd']): 
                auth_token = encode_auth_token(username)
                self.set_status(200)
                self.write({'status': 'success', 'message': 'Logged in successfully', 'auth_token': auth_token })
                self.finish()
                return
            else:
                self.set_status(500)
                self.write({'status': 'fail', 'message': 'Invalid loggin attempt' })
                self.finish()
                return

        except:
            self.set_status(500)
            self.write({'status': 'fail', 'message': 'Invalid loggin attempt' })
            self.finish()
            return