HTTP请求在Alexa的AWS Lambda函数中失败

Question

I am trying to return data from an external api in my inline Lambda function but when I test this in the developer console for Alexa, I get 'There was a problem with the requested skills response' and I can't work out why. Also, as I am doing this from the AWS console, I can't console.log to see what it actually being returned.
(I have removed the default intents for the sake of the post)

const request = require('request');

const handlers = {
'LaunchRequest': function () {
    this.emit(':ask', 'Welcome');
},
'GiveUpdateIntent': function (){
    var slot = this.event.request.intent.slots.line.value;

    httpGet(slot, (theResult) => {
            this.response.speak(theResult);
            this.emit(':responseReady');
        });

}

};
function httpGet(query, callback) {
var options = {
    host: 'api.tfl.gov.uk',
    path: '/line/' + encodeURIComponent(query) + '/status',
    method: 'GET',
};

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

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

    //return the data when streaming is complete
    res.on('end', () => {
        console.log(responseString[0]);
        callback(responseString[0]);
    });

});
req.end();
}


exports.handler = function (event, context, callback) {
    const alexa = Alexa.handler(event, context, callback);
    alexa.APP_ID = APP_ID;
    alexa.registerHandlers(handlers);
    alexa.execute();
};

Answer 1

"There was a problem with the requested skills response" generally means that the response from your skill was not in the expected format.

Your API request

Ex: vicotria

https://api.tfl.gov.uk/Line/victoria/Status  

returns a JSON, and you can't directly pass it Alexa as response. Before you send it back to Alexa, take out status that you actually want Alexa to speak. Then put that into a meaningful sentence that any skill user will understand and send it back.

For example you can return something like:

var speech = "Status severity description for " + 
              this.event.request.intent.slots.line.value +
              " is "
              + responseBody[0].lineStatuses.statusSeverityDescription;
this.emit(':ask',speech, "your re-prompt here");

This is a sample JSON that I got

[
  {
    "$type": "Tfl.Api.Presentation.Entities.Line, Tfl.Api.Presentation.Entities",
    "id": "victoria",
    "name": "Victoria",
    "modeName": "tube",
    "disruptions": [],
    "created": "2018-07-31T12:11:08.477Z",
    "modified": "2018-07-31T12:11:08.477Z",
    "lineStatuses": [
      {
        "$type": "Tfl.Api.Presentation.Entities.LineStatus, Tfl.Api.Presentation.Entities",
        "id": 0,
        "statusSeverity": 10,
        "statusSeverityDescription": "Good Service",
        "created": "0001-01-01T00:00:00",
        "validityPeriods": []
      }
    ],
    "routeSections": [],
    "serviceTypes": [
      {
        "$type": "Tfl.Api.Presentation.Entities.LineServiceTypeInfo, Tfl.Api.Presentation.Entities",
        "name": "Regular",
        "uri": "/Line/Route?ids=Victoria&serviceTypes=Regular"
      },
      {
        "$type": "Tfl.Api.Presentation.Entities.LineServiceTypeInfo, Tfl.Api.Presentation.Entities",
        "name": "Night",
        "uri": "/Line/Route?ids=Victoria&serviceTypes=Night"
      }
    ],
    "crowding": {
      "$type": "Tfl.Api.Presentation.Entities.Crowding, Tfl.Api.Presentation.Entities"
    }
  }
]

CloudWatch : Always make use of CloudWatch to see the logs of your Lambda function, you will get a link under Monitoring tab of your Lambda Function.

Configuring Lambda Test Events : You can test you Lambda code right from your inline editor by configuring Lambda Test Events under Test menu of your inline editor. A function can have up to 10 test events.

Answer 2

This is because your handler is returning before the callback is called. I strongly suggest to move away from callback based development in NodeJS and to use Promise instead.

I just answered a similar question, and provided sample code with promises. Check it here How to make an asynchronous api call for Alexa Skill application with a Lambda function?

Answer 3

The issue turned out to be with using http itself instead of https.

The only response back that I was getting was a status code of 302 which is a redirection because the api I was calling changes all http requests to https.

Therefore, I changed my import to https and used the https.get method (instead of http.get) to call the api and the correct response was returned.