无法在对话框流API V2 DB调用中获得期望的结果

Question

我正在尝试连接到MySQL db，获取结果并将其传递给将显示给用户的代理。由于DB查询是异步的，所以在解析数据之后，我已经使用允诺来获得回调并发送响应。我确实在日志中获得响应，但函数执行在此之前结束，它似乎不等待，然后是调用。

以下是代码：

var sqlQuery = '';
  var dbResults = '';
exports.dialogflowFirebaseFulfillment = 
functions.https.onRequest((request, response) => {
  const agent = new WebhookClient({ request, response });
  var reply = '';


  function welcome(agent) {
    agent.add(`Welcome to my agent!`);
  }

  function fallback(agent) {
    agent.add(`I didn't understand`);
    agent.add(`I'm sorry, can you try again?`);
}

    function getBalance(){

                sqlQuery = 'select * from master_balance where account_no = \'1234567\'';

                callDB().then((results) => {

                var balance_type = request.body.queryResult.parameters['balance_type'];
                if(balance_type == 'SMS'){
                    console.log('In SMS');
                    reply = 'You have '+ results[0].bal_sms +' SMS left in your account';
                }
                else if(balance_type == 'Voice'){
                    console.log('In Voice-- from DB--'+results[0].bal_call);
                    reply = 'Your Voice balance is $ '+results[0].bal_call;
                }
                else if(balance_type == 'Data'){
                    console.log('In Data');
                    reply = 'You have '+results[0].bal_data +' MB left in your account';
                }
                else{
                    console.log('In Ahh');
                    reply = 'Ahh, there seems to be some issue. Please wait';
                }
                agent.add(reply);
                 return 1;
                 }).catch((error) => {
                     console.log('in catch----'+error);

                    });
        return 1;
     }



  let intentMap = new Map();
  intentMap.set('Default Welcome Intent', welcome);
  intentMap.set('Default Fallback Intent', fallback);
  intentMap.set('Query.Balance', getBalance);

  agent.handleRequest(intentMap);
});

function callDB() {
        return new Promise((resolve, reject) => {
        console.log('-- In callDB--'+sqlQuery);
        try {
            var connection = mysql.createConnection({
                socketPath: '/cloudsql/' + connectionName,
                user: dbUser,
                password: dbPass,
                database: dbName
            });
            connection.query(sqlQuery, function (error, results, fields) {
                if (!error) {

                    console.log('--In no error 2--'+results[0]);
                    resolve(results);

                } else {

                    let output = {'speech': 'Error. Query Failed.', 'displayText': 'Error. Query Failed.'};
                    console.log('--- in else----'+error);

                    reject(results);

                }
            });
            connection.end();

        } catch (err) {
            let results = {'speech': 'try-cacth block error', 'displayText': 'try-cacth block error'};
            console.log(results);
            reject(results);

        }

    }
    );
}

请帮我解决我可能做错的事。另一件事是，当谈到Node时，我是个菜鸟。

提前谢谢!！

Answer 1

问题是，如果使用异步函数，那么意图处理程序也必须返回承诺。仅作为then()子句的一部分发送答复是不够的，还必须返回then()是其一部分的承诺。

在您的例子中，这看起来相当容易。在getBalance()函数中，您将返回callDB().then().catch()结果，这是一个承诺。(then()和‘`catch()返回一个承诺)

return callDB().then((results) => {
  ....