this is a lambda function to be used by an alexa homeskill. this will write to a sns topic, the idea is to have another lambda function subscribe, and act

alexa homeskill lambda to sns

/**
 * This sample demonstrates a simple driver  built against the Alexa Lighting Api.
 * For additional details, please refer to the Alexa Lighting API developer documentation 
 * https://developer.amazon.com/public/binaries/content/assets/html/alexa-lighting-api.html
 */
var https = require('https');
var AWS = require('aws-sdk');

var REMOTE_CLOUD_BASE_PATH = '/';
var REMOTE_CLOUD_HOSTNAME = 'www.amazon.com';

/**
 * Main entry point.
 * Incoming events from Alexa Lighting APIs are processed via this method.
 */
exports.handler = function(event, context) {

    log('Input', event);

    switch (event.header.namespace) {
        
        /**
         * The namespace of "Discovery" indicates a request is being made to the lambda for
         * discovering all appliances associated with the customer's appliance cloud account.
         * can use the accessToken that is made available as part of the payload to determine
         * the customer.
         */
        case 'Alexa.ConnectedHome.Discovery':
            handleDiscovery(event, context);
            break;

            /**
             * The namespace of "Control" indicates a request is being made to us to turn a
             * given device on, off or brighten. This message comes with the "appliance"
             * parameter which indicates the appliance that needs to be acted on.
             */
        case 'Alexa.ConnectedHome.Control':
            handleControl(event, context);
            break;

            /**
             * We received an unexpected message
             */
        default:
            log('Err', 'No supported namespace: ' + event.header.namespace);
            context.fail('Something went wrong');
            break;
    }
};

/**
 * This method is invoked when we receive a "Discovery" message from Alexa Smart Home Skill.
 * We are expected to respond back with a list of appliances that we have discovered for a given
 * customer. 
 */
function handleDiscovery(accessToken, context) {

    /**
     * Crafting the response header
     */
    var headers = {
        namespace: 'Alexa.ConnectedHome.Discovery',
        name: 'DiscoverAppliancesResponse',
        payloadVersion: '2'
    };

    /**
     * Response body will be an array of discovered devices.
     */
    var appliances = [];

    var applianceDiscovered = {
        applianceId: 'Sample-Device-ID',
        manufacturerName: 'SmartThings',
        modelName: 'ST01',
        version: 'VER01',
        friendlyName: 'kitchen light',
        friendlyDescription: 'light in kitchen',
        isReachable: true,
        actions: [
            "TurnOn",
            "TurnOff"
        ],
        additionalApplianceDetails: {
            /**
             * OPTIONAL:
             * We can use this to persist any appliance specific metadata.
             * This information will be returned back to the driver when user requests
             * action on this appliance.
             */
            'fullApplianceId': '2cd6b650-c0h0-4062-b31d-7ec2c146c5ea'
        }
    };
    appliances.push(applianceDiscovered);

    /**
     * Craft the final response back to Alexa Smart Home Skill. This will include all the 
     * discoverd appliances.
     */
    var payloads = {
        discoveredAppliances: appliances
    };
    var result = {
        header: headers,
        payload: payloads
    };

    log('Discovery', result);

    context.succeed(result);
}

/**
 * Control events are processed here.
 * This is called when Alexa requests an action (IE turn off appliance).
 */
function handleControl(event, context) {
    /**
     * Fail the invocation if the header is unexpected. This example only demonstrates
     * turn on / turn off, hence we are filtering on anything that is not SwitchOnOffRequest.
     */
    if (event.header.namespace != 'Alexa.ConnectedHome.Control' || (event.header.name != 'TurnOnRequest' && event.header.name != 'TurnOffRequest')) {
        context.fail(generateControlError(event.header.name, 'UNSUPPORTED_OPERATION', 'Unrecognized operation'));
    }

    if (event.header.namespace === 'Alexa.ConnectedHome.Control' && (event.header.name === 'TurnOnRequest' || event.header.name === 'TurnOffRequest')) {

        /**
         * Retrieve the appliance id and accessToken from the incoming message.
         */
        var applianceId = event.payload.appliance.applianceId;
        var accessToken = event.payload.accessToken.trim();
        log('applianceId', applianceId);



        var serverError = function (e) {
            log('Error', e.message);
            /**
             * Craft an error response back to Alexa Smart Home Skill
             */
            context.fail(generateControlError(event.header.name, 'DEPENDENT_SERVICE_UNAVAILABLE', 'Unable to connect to server'));
        };

        /*var callback = function(response) {
            var str = '';

            response.on('data', function(chunk) {
                str += chunk.toString('utf-8');
            });

            response.on('end', function() {
                
                
            });

            response.on('error', serverError);
        };*/

        AWS.config.region = 'us-east-1';
        
        var sns = new AWS.SNS();
        var message = "";
        
        log('event.header.name', event.header.name);
        
        if (event.header.name === 'TurnOnRequest') {
          message = '{"topic": "0", "action": "true"}';
        } else if (event.header.name === 'TurnOffRequest') {
          message = '{"topic": "0", "action": "false"}';
        }
        
        sns.publish({
            Message: message,
            TopicArn: '*****FILL IN YOUR TOPIC HERE******'
        }, function(err, data) {
            if (err) {
                log('sns err', err.stack);
                serverError;
            }
            log('sns','push sent');
            log('sns',data);
            log('event.header.name-end', event.header.name);
            
            var headers = {
                namespace: 'Alexa.ConnectedHome.Control',
                name: event.header.name === 'TurnOnRequest' ? 'TurnOnConfirmation' : 'TurnOffConfirmation',
                payloadVersion: '2',
                messageId: event.header.messageId
            };
            var payloads = {
                success: true
            };
            var result = {
                header: headers,
                payload: payloads
            };
            log('Done with result', result);
            context.succeed(result);
        });
        
        /**
         * Make an HTTPS call to remote endpoint.
         */
        //https.get(options, callback)
            //.on('error', serverError).end();
    }
}

/**
 * Utility functions.
 */
function log(title, msg) {
    console.log('*************** ' + title + ' *************');
    console.log(msg);
    console.log('*************** ' + title + ' End*************');
}

function generateControlError(name, code, description) {
    var headers = {
        namespace: 'Alexa.ConnectedHome.Control',
        name: name,
        payloadVersion: '2'
    };

    var payload = {
        exception: {
            code: code,
            description: description
        }
    };

    var result = {
        header: headers,
        payload: payload
    };

    return result;
}