Node.js Lambda 函数从 REST 调用将“响应无效”返回给 Alexa 服务模拟器答案

【问题标题】：Node.js Lambda function returns "The response is invalid" back to Alexa Service Simulator from REST callNode.js Lambda 函数从 REST 调用将“响应无效”返回给 Alexa 服务模拟器
【发布时间】：2017-07-30 22:57:15
【问题描述】：

在 node.js Lambda 函数和 Alexa 之间对 API 进行 REST 调用时遇到问题。我正在使用request 库通过帐户链接技能进行呼叫。我只为意图设置了一个示例话语，模拟器可以看到这一点。

此外，cloudwatch 日志显示来自 api 端点的 200 响应代码以及从 console.logs 到 CW 的 API 返回的任何数据。

'use strict';
var http = require('http');
var request = require('request');
var Alexa = require('alexa-sdk');
var APP_ID = "amzn1.ask.skill.XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXX";

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

var handlers = {
   'LaunchRequest': function () {
        this.emit(':tell', 'Hi!');
   },

   'ApiWelcomeIntent': function () {
        request('https://some.web/api', function (error, response, body) {
            if (!error && response.statusCode == 200) {
            // from within the callback, write data to response, essentially returning it.
                var speechOutput = JSON.stringify(body);
                console.log(body + " :Raw output?");
                console.log(speechOutput + ' :JSON stringified');
                console.log(response.statusCode);
                this.emit(':tell', speechOutput);
            } else {
                console.log(error + ' : ' + response.statusCode);
                this.emit(':tell', 'There was an error');
            }
        });
    },

    'AMAZON.HelpIntent': function () {} //.........And other built in intents.

    }
};

我猜它与我要求 Alexa“发出/告诉”的 SpeechOutput 格式有关？

【问题讨论】：

标签： node.js aws-lambda alexa alexa-skills-kit alexa-skill

【解决方案1】：

不，它与speechOutput的格式无关。问题是在执行request 方法的回调时，对this 的引用丢失了。要解决这个问题，请在调用 request 之前保留对 this 的引用（例如，将 this 分配给名为 self 的变量）：

'use strict';
var http = require('http');
var request = require('request');
var Alexa = require('alexa-sdk');
var APP_ID = "amzn1.ask.skill.XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXX";

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

var handlers = {
   'LaunchRequest': function () {
        this.emit(':tell', 'Hi!');
   },

   'ApiWelcomeIntent': function () {
        self = this

        request('https://some.web/api', function (error, response, body) {
            if (!error && response.statusCode == 200) {
            // from within the callback, write data to response, essentially returning it.
                var speechOutput = JSON.stringify(body);
                console.log(body + " :Raw output?");
                console.log(speechOutput + ' :JSON stringified');
                console.log(response.statusCode);
                self.emit(':tell', speechOutput); // USE SELF HERE
            } else {
                console.log(error + ' : ' + response.statusCode);
                self.emit(':tell', 'There was an error'); // AND HERE AS WELL
            }
        });
    },

    'AMAZON.HelpIntent': function () {} //.........And other built in intents.

    }
};

【讨论】：

嘿@renansdias 你的回答听起来是正确的，但我在使用自我后仍然面临这个问题。你能在stackoverflow.com/questions/45613412/… 上查看我的代码吗
@devutkarsh 你仍然面临这个问题吗？
对不起@devutkarsh 完全错过了这个。是的，您是否仍然面临这个问题？
@renansdias - 现在已解决。谢谢！我也接受了你的回答:)

【解决方案2】：

您仅因为 NodeJS 的异步调用行为而面临问题，而与请求调用无关。您可以通过使用 Promise 或使用方法回调来解决此问题。下面是sn-p。

'use strict';
var http = require('http');
var request = require('request');
var Alexa = require('alexa-sdk');
var APP_ID = "amzn1.ask.skill.XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXX";

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

var handlers = {
   'LaunchRequest': function () {
        this.emit(':tell', 'Hi!');
   },

   'ApiWelcomeIntent': function () {
        requestAPI( (message) => {
            this.emit(':tell', message);
        });
    },
    'AMAZON.HelpIntent': function () {} //.........And other built in intents.

    }
};

function requestAPI(callback) {
    request('https://some.web/api', function (error, response, body) {
        if (!error && response.statusCode == 200) {
        // from within the callback, write data to response, essentially returning it.
            var speechOutput = JSON.stringify(body);
            console.log(body + " :Raw output?");
            console.log(speechOutput + ' :JSON stringified');
            console.log(response.statusCode);
            callback(speechOutput);
        } else {
            console.log(error + ' : ' + response.statusCode);
            callback('There was an error');
        }
    });
}

【讨论】：