Azure Function code for a demo Alexa Skill handler for the Christmas Jumper project

index.js

// Alexa skill handler for the "Citrix" demo skill.
//
// This runs as an Azure Function and must have the NPM libraries installed into the
// Function App image: ensure that package.json is populated with the required
// dependencies and follow the instructions at
// https://docs.microsoft.com/en-us/azure/azure-functions/functions-reference-node#node-version-and-package-management
// 
// Example package.json:
// {
//   "dependencies": {
//     "azure-iothub": "^1.1.17",
//     "azure-iot-common": "^1.2.0"
//   }
// }
//
// Secrets are stored as Application Settings and accessed here via environment variables.
// They are:
//    CFG_IOTHUB_CONNECTION_STRING - connection string for the Azure IoT Hub
//    CFG_ALEXA_SKILL_ID_CITRIX - Alexa Skill App ID
//
// MIT License
//
// Copyright (c) [2017] [Citrix Systems, Inc]
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

var Client = require('azure-iothub').Client;
var Message = require('azure-iot-common').Message;
var querystring = require('querystring');

// The deviceName of the xmas jumper demo
var deviceNameXmas = 'xmas';

// Functions to help build Alexa responses
function addToResponseSpeech(response, text) {
    response.response.outputSpeech = {
        'type': 'PlainText',
        'text': text
    };
}

// These are templates for the side-effects the skill may have. Each returns an object
// that will go on the queue for processing.
function sideEffectIoT(deviceName, message) {
    return {
        fn: handleCallIoT,
        args: {
            deviceName: deviceName,
            message: message
        }
    }
}

// Side-effect handlers. Each one will do its thing and then call a common callback.
// The callback will either call the next handler, or if no more are left, complete
// the original Alexa request.
function sideEffectHandlerCallback(context, sideEffectList, err, result) {
    if (err) {
        // Do not call any further handlers. If the previous handler did not
        // set an error code on the response then do this now.
        if (!context.res || !context.res.status) {
            context.res = {
                status: 500,
                body: "Handler error: " + err
            };
        }
        context.done();
        return;
    }

    var next = sideEffectList.pop();
    if (!next) {
        // No more handlers, complete the request
        context.done();
        return;
    }

    // Call the next handler
    next.fn(context, sideEffectHandlerCallback.bind(null, context, sideEffectList), next.args);
}

function callSideEffectHandlers(context, sideEffectList) {
    sideEffectHandlerCallback(context, sideEffectList, null, null);
}

function handleCallIoT(context, callback, args) {
    if (!process.env.CFG_IOTHUB_CONNECTION_STRING) {
        context.log('Application setting "CFG_IOTHUB_CONNECTION_STRING" missing.');
        context.res = {
            status: 500,
            body: "IoT Hub not configured."
        };
        callback("IoT Hub not configured", null);
        return;
    }

    var serviceClient = Client.fromConnectionString(process.env.CFG_IOTHUB_CONNECTION_STRING);
    serviceClient.open(function (err) {
        if (err) {
            context.log('Could not connect: ' + err.message);
            context.res = {
                status: 500,
                body: "Could not connect to Iot Hub: " + err.message
            };
            context.done();
        } else {
            context.log('Service client connected');
            var msg = new Message(args.message);
            msg.ack = 'full';
            msg.messageId = "My Message ID";
            context.log('Sending message: ' + msg.getData());
            serviceClient.send(args.deviceName, msg, callback);
        }
    });
}

// Main Alexa skill handler
module.exports = function (context, req) {
    context.log('JavaScript HTTP trigger function processed a request.', JSON.stringify(req, null, 2));

    if (!process.env.CFG_ALEXA_SKILL_ID_CITRIX) {
        context.log('Application setting "CFG_ALEXA_SKILL_ID_CITRIX" missing.');
        context.res = {
            status: 500,
            body: "Alexa skill ID config missing"
        };
        context.done();
        return;
    }

    // Check that we're being called by the Alexa infrastructure
    context.log('Application ID', req.body.session.application.applicationId);
    if (req.body.session.application.applicationId != process.env.CFG_ALEXA_SKILL_ID_CITRIX) {
        context.res = {
            status: 403,
            body: "Unauthorized application ID"
        };
        context.done();
        return;
    }

    var response = {
        'version': '1.0',
        'sessionAttributes': {},
        'response': {
            'shouldEndSession': true
        }
    };

    // Build a list of side-effect actions to take
    sideEffects = [];

    if (req.body.request.type == "IntentRequest") {
        var intent = req.body.request.intent;
        switch (intent.name) {
        case "XmasIntent":
            var color = req.body.request.intent.slots.color.value;
            sideEffects.push(sideEffectIoT(deviceNameXmas, color));
            addToResponseSpeech(response, "OK");
            break;
        }
    }

    context.res = {
        // status: 200, /* Defaults to 200 */
        body: response
    };

    callSideEffectHandlers(context, sideEffects);
};