如何使用Lambda函數對Alexa Skill應用程序進行異步api調用？

Question

我想從Lambda函數調用api。 我的處理程序由包含兩個必需插槽的意圖觸發。 因此，我事先不知道我將返回Dialog.Delegate指令還是來自api請求的響應。 在調用Intent處理程序時，如何保證這些返回值？

這是我的處理程序：

const FlightDelayIntentHandler = {
  canHandle(handlerInput) {
    return handlerInput.requestEnvelope.request.type === 'IntentRequest'
      && handlerInput.requestEnvelope.request.intent.name === 'MyIntent';
  },

  handle(handlerInput) {
    const request = handlerInput.requestEnvelope.request;

    if (request.dialogState != "COMPLETED"){
      return handlerInput.responseBuilder
        .addDelegateDirective(request.intent)
        .getResponse();
    } else {
      // Make asynchronous api call, wait for the response and return.
      var query = 'someTestStringFromASlot';

      httpGet(query,  (result) => {
        return handlerInput.responseBuilder
          .speak('I found something' + result)
          .reprompt('test')
          .withSimpleCard('Hello World', 'test')
          .getResponse();
      });
    }
  },
};

這是我的幫助器函數，它發出請求：

const https = require('https');

function httpGet(query, callback) {
    var options = {
        host: 'myHost',
        path: 'someTestPath/' + query,
        method: 'GET',
        headers: {
            'theId': 'myId'
        }
    };

    var req = https.request(options, res => {
        res.setEncoding('utf8');
        var responseString = "";

        //accept incoming data asynchronously
        res.on('data', chunk => {
            responseString = responseString + chunk;
        });

        //return the data when streaming is complete
        res.on('end', () => {
            console.log('==> Answering: ');
            callback(responseString);
        });

    });
    req.end();
}

因此，我懷疑我將不得不使用Promise並在我的handle函數前面放置一個“異步”嗎？ 我對這一切都很陌生，所以我不知道這意味着什么，尤其是考慮到我有兩個不同的返回值，一個是直接返回值，另一個是延遲值。 我該如何解決？

先感謝您。

Answer 1

正如您所懷疑的那樣，您的處理程序代碼在異步調用http.request之前已經完成，因此Alexa SDK沒有從handle函數接收任何返回值，並且將向Alexa返回無效的響應。

我稍加修改了您的代碼，以在筆記本電腦上本地運行它來說明問題：

const https = require('https');

function httpGet(query, callback) {
    var options = {
        host: 'httpbin.org',
        path: 'anything/' + query,
        method: 'GET',
        headers: {
            'theId': 'myId'
        }
    };

    var req = https.request(options, res => {
        res.setEncoding('utf8');
        var responseString = "";

        //accept incoming data asynchronously
        res.on('data', chunk => {
            responseString = responseString + chunk;
        });

        //return the data when streaming is complete
        res.on('end', () => {
            console.log('==> Answering: ');
            callback(responseString);
        });

    });
    req.end();
}

function FlightDelayIntentHandler() {

    // canHandle(handlerInput) {
    //   return handlerInput.requestEnvelope.request.type === 'IntentRequest'
    //     && handlerInput.requestEnvelope.request.intent.name === 'MyIntent';
    // },

    // handle(handlerInput) {
    //   const request = handlerInput.requestEnvelope.request;

    // if (request.dialogState != "COMPLETED"){
    //     return handlerInput.responseBuilder
    //       .addDelegateDirective(request.intent)
    //       .getResponse();
    //   } else {
        // Make asynchronous api call, wait for the response and return.
        var query = 'someTestStringFromASlot';

        httpGet(query,  (result) => {
            console.log("I found something " + result);

        //   return handlerInput.responseBuilder
        //     .speak('I found something' + result)
        //     .reprompt('test')
        //     .withSimpleCard('Hello World', 'test')
        //     .getResponse();
        });

        console.log("end of function reached before httpGet will return");
    //   }
    // }
}

FlightDelayIntentHandler();

要運行此代碼，請不要忘記npm install http ，然后是node test.js 它產生

stormacq:~/Desktop/temp $ node test.js
end of function reached before httpGet will return
==> Answering:
I found something {
  "args": {},
  "data": "",
... 

因此，關鍵是要等待http get返回，然后再將響應返回給Alexa。 為此，我建議修改您的httpGet函數以返回承諾，而不是使用回調。

修改后的代碼是這樣的（我保留了原始代碼作為注釋）

const https = require('https');

async function httpGet(query) {
    return new Promise( (resolve, reject) => {
        var options = {
            host: 'httpbin.org',
            path: 'anything/' + query,
            method: 'GET',
            headers: {
                'theId': 'myId'
            }
        };

        var req = https.request(options, res => {
            res.setEncoding('utf8');
            var responseString = "";

            //accept incoming data asynchronously
            res.on('data', chunk => {
                responseString = responseString + chunk;
            });

            //return the data when streaming is complete
            res.on('end', () => {
                console.log('==> Answering: ');
                resolve(responseString);
            });

            //should handle errors as well and call reject()!
        });
        req.end();

    });

}



async function FlightDelayIntentHandler() {

        // canHandle(handlerInput) {
    //   return handlerInput.requestEnvelope.request.type === 'IntentRequest'
    //     && handlerInput.requestEnvelope.request.intent.name === 'MyIntent';
    // },

    // handle(handlerInput) {
    //   const request = handlerInput.requestEnvelope.request;

    // if (request.dialogState != "COMPLETED"){
    //     return handlerInput.responseBuilder
    //       .addDelegateDirective(request.intent)
    //       .getResponse();
    //   } else {
        // Make asynchronous api call, wait for the response and return.
        var query = 'someTestStringFromASlot';

        var result = await httpGet(query);
        console.log("I found something " + result);

        //   return handlerInput.responseBuilder
        //     .speak('I found something' + result)
        //     .reprompt('test')
        //     .withSimpleCard('Hello World', 'test')
        //     .getResponse();
        //});

        console.log("end of function reached AFTER httpGet will return");
    //   }
    // }
}

FlightDelayIntentHandler();

運行此代碼將產生：

stormacq:~/Desktop/temp $ node test.js
==> Answering:
I found something{
  "args": {},
  "data": "",
...
end of function reached AFTER httpGet will return