Jang-Soo Lee
Created November 30, 2016 © MIT

lirrbits

A quick and easy way to get the next train times for the Long Island Railroad

IntermediateWork in progress5 hours49
lirrbits

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Code

index.js

JavaScript
Use in conjunction with dependencies found in package.json
'use strict';

var request = require('request');
var os = require('os');
/**
 * This sample demonstrates a skill built with the Amazon Alexa Skills Kit.
 * The Intent Schema, Custom Slots, and Sample Utterances for this skill, as well as
 * testing instructions are located at http://lirrbits.com/alexa
 */


//Start: Initialize cache, so that warm starts can take advantage of it being populated.
var cache;
var thinkIAmOk = true;
let apiKey = process.env.traintime_key;

function buildCache() {
  request("https://traintime.lirr.org/api/StationsAll?api_key=" + apiKey, function(err, response, body){
    if (err) {
      console.log('ran into error building cache');
      setTimeout(function() {buildCache(); }, 10);
      return;
    }
    cache = JSON.parse(body);
    console.log('cache set up');
  });
}
var none = buildCache();
//End: Initialize cache, so that warm starts can take advantage of it being populated.

// --------------- Helpers that build all of the responses -----------------------

function buildSpeechletResponse(title, output, repromptText, shouldEndSession) {
    return {
        outputSpeech: {
            type: 'PlainText',
            text: output,
        },
        card: {
            type: 'Standard',
            title: 'LIRRBits.com',
            text: `${output}`,
            image: {
              smallImageUrl: 'https://brucel.ee/smallLogoLB.png',
              largeImageUrl: 'https://brucel.ee/largeLogoLB.png'
            }
        },
        reprompt: {
          outputSpeech: {
            type: "PlainText",
            text: repromptText
          }
        },
        shouldEndSession,
    };
}

function buildResponse(sessionAttributes, speechletResponse) {
    return {
        version: '1.0',
        sessionAttributes,
        response: speechletResponse,
    };
}


// --------------- Functions that control the skill's behavior -----------------------

function getWelcomeResponse(callback) {
    // If we wanted to initialize the session to have some attributes we could add those here.
    const sessionAttributes = {};
    const cardTitle = 'Welcome';
    const speechOutput = 'Welcome to lir bits. What would you like to know?';

    callback(sessionAttributes,
        buildSpeechletResponse(cardTitle, speechOutput, 'You can ask lir bits about the next trains from one station to another, or to give station information for a given station.', false));
}

function handleSessionEndRequest(callback) {
    const cardTitle = 'Session Ended';
    const speechOutput = 'Have a nice day!';
    // Setting this to true ends the session and exits the skill.
    const shouldEndSession = true;

    callback({}, buildSpeechletResponse(cardTitle, speechOutput, null, shouldEndSession));
}

// --------------- Events -----------------------

/**
 * Called when the session starts.
 */
function onSessionStarted(sessionStartedRequest, session) {
    console.log(`onSessionStarted requestId=${sessionStartedRequest.requestId}, sessionId=${session.sessionId}`);
}

/**
 * Called when the user launches the skill without specifying what they want.
 */
function onLaunch(launchRequest, session, callback) {
    console.log(`onLaunch requestId=${launchRequest.requestId}, sessionId=${session.sessionId}`);

    // Dispatch to your skill's launch.
    getWelcomeResponse(callback);
}

/**
 * Given StationOne and StationTwo information in an intent, as well as an api
 * key, give either full, extended information about the next few trains, or
 * just the departure times.
 */
function getTimes(intent, full, callback) {
  if (!cache) {
    console.log('still warming...');
    setTimeout(function() {getTimes(intent, full, callback);}, 25);
    return;
  }

  //Request all stations from the API, so that we can map a station name to its
  //abbreviation
  var normalizedStationOne = intent.slots.StationOne.value && intent.slots.StationOne.value.toLowerCase() || "";
  var normalizedStationTwo = intent.slots.StationTwo.value && intent.slots.StationTwo.value.toLowerCase() || "";

  var stations = cache;
  var stationOneAbbr;
  var stationTwoAbbr;

  for (var i in stations.Stations) {
    cache[stations.Stations[i].ABBR] = stations.Stations[i].NAME;
    if (stations.Stations[i].NAME.toLowerCase() === normalizedStationOne){
      stationOneAbbr = stations.Stations[i].ABBR;
    }
    if (stations.Stations[i].NAME.toLowerCase() === normalizedStationTwo){
      stationTwoAbbr = stations.Stations[i].ABBR;
    }
  }
  if (!stationOneAbbr || !stationTwoAbbr) {
    //If we can't find the station, give the user information that we could
    //not find the station.
    callback({},
      buildSpeechletResponse("card", "I was unable to determine times from " + normalizedStationOne + " to " + normalizedStationTwo, 'reprompt', true));
  } else {
    //Otherwise, ask the API for the metadata around the next few trains from
    //the first station to the second
    request("https://traintime.lirr.org/api/TrainTime?api_key=" + apiKey + "&startsta=" + stationOneAbbr + "&endsta=" + stationTwoAbbr, function(err, response, body){
      if (err) {
        callback({},
          buildSpeechletResponse("card", "I ran into an error trying to determine times from " + normalizedStationOne + " to " + normalizedStationTwo, 'reprompt', true));
        return;
      }
      var outs = JSON.parse(body);
      var info = "";
      //Return up to five trips, to avoid overwhelming the user
      for (var k = 0; k < outs.TRIPS.length && k < 5; k++) {
        //Give the start time by looking at the first leg and the first stop
        info = info + outs.TRIPS[k].LEGS[0].STOPS[0].TIME + ", ";
        //User may not want the full set of information
        if (!full){
          continue;
        }
        //Peak and offpeak denote cost differences in ticket prices
        if (outs.TRIPS[k].PEAK_INDICATOR === 1) {
          info = info + " Peak, ";
        } else {
          info = info + " Off Peak, ";
        }
        let legs = outs.TRIPS[k].LEGS;
        //Check for whether one or more connections are needed, and add that
        //information to the response
        if (outs.TRIPS[k].LEGS.length !== 1) {
          for (var legIndex = 0; legIndex < outs.TRIPS[k].LEGS.length - 1; legIndex++) {
            let leg = legs[legIndex];
            info = info + " Connecting at " + cache[leg.STOPS[leg.STOPS.length - 1].STATION] + ", ";
          }
        }
        let finalLeg = legs[legs.length - 1];
        let finalStop = finalLeg.STOPS[finalLeg.STOPS.length - 1];
        info = info + finalStop.TIME + " Arrival. ";
      }
      if (info.length > 0) {
        info = info.substring(0, info.length - 2);
        info = "These are the next departures from " + normalizedStationOne + " to " + normalizedStationTwo + ": " + info ;
      } else {
        info = "I was unable to find information from " + normalizedStationOne + " to " + normalizedStationTwo;
      }
      callback({},
        buildSpeechletResponse("card", info, 'reprompt', true));

    });
  }
}

function getStationInformation(intent, callback) {
  if (!cache) {
    console.log('still warming...');
    setTimeout(function() {getStationInformation(intent, callback);}, 25);
    return;
  }
  var stations = cache;
  for (var i in stations.Stations) {
    if (stations.Stations[i].NAME.toLowerCase() === intent.slots.Station.value){
      let ticketMachine = stations.Stations[i].TICKETMACHINE;
      if (ticketMachine.indexOf('None') === 0) {
        ticketMachine = "No ticket machine information is listed for this station."
      }
      callback({},
        buildSpeechletResponse("card", "The station is located at: " + stations.Stations[i].LOCATION + ". " + ticketMachine, 'reprompt', true));
      return;
    }
  }
  callback({},
    buildSpeechletResponse("card", "I wasn't able to find station information for " + intent.slots.Station.value, 'reprompt', true));
}

/**
 * Called when the user specifies an intent for this skill.
 */
function onIntent(intentRequest, session, callback) {
    console.log(`onIntent requestId=${intentRequest.requestId}, sessionId=${session.sessionId}`);

    const intent = intentRequest.intent;
    const intentName = intentRequest.intent.name;

    // Dispatch to your skill's intent handlers
    console.log(intentName);
    if (intentName === 'GetStationInformation') {
      getStationInformation(intent, callback);
    } else if (intentName === 'GetFullTimesInformation') {
      getTimes(intent, true, callback);
    } else if (intentName === 'GetTimesInformation') {
      getTimes(intent, false, callback);
    } else if (intentName === 'AMAZON.HelpIntent') {
      callback({},
        buildSpeechletResponse('Help', 'You can ask lir bits about the next trains from one station to another, or to give station information for a given station.', 'What would you like to ask lir bits?', false));
    } else if (intentName === 'AMAZON.StopIntent' || intentName === 'AMAZON.CancelIntent') {
        handleSessionEndRequest(callback);
    } else {
        throw new Error('Invalid intent');
    }
}

/**
 * Called when the user ends the session.
 * Is not called when the skill returns shouldEndSession=true.
 */
function onSessionEnded(sessionEndedRequest, session) {
    console.log(`onSessionEnded requestId=${sessionEndedRequest.requestId}, sessionId=${session.sessionId}`);
    // Add cleanup logic here
}


// --------------- Main handler -----------------------

// Route the incoming request based on type (LaunchRequest, IntentRequest,
// etc.) The JSON body of the request is provided in the event parameter.
exports.handler = (event, context, callback) => {
    try {
        console.log(`event.session.application.applicationId=${event.session.application.applicationId}`);

        if (event.session.application.applicationId !== 'amzn1.ask.skill.b0ebfcb9-9323-4470-914f-d3e001a3e0ba') {
             callback('Invalid Application ID');
        }

        if (event.session.new) {
            onSessionStarted({ requestId: event.request.requestId }, event.session);
        }

        if (event.request.type === 'LaunchRequest') {
            onLaunch(event.request,
                event.session,
                (sessionAttributes, speechletResponse) => {
                    callback(null, buildResponse(sessionAttributes, speechletResponse));
                });
        } else if (event.request.type === 'IntentRequest') {
            onIntent(event.request,
                event.session,
                (sessionAttributes, speechletResponse) => {
                    callback(null, buildResponse(sessionAttributes, speechletResponse));
                });
        } else if (event.request.type === 'SessionEndedRequest') {
            onSessionEnded(event.request, event.session);
            callback();
        }
    } catch (err) {
        callback(err);
    }
};

package.json

JSON
dependencies!
{
  "name": "lirrbits-alexa",
  "version": "1.0.0",
  "description": "lirrbits-alexa",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "repository": {
    "type": "git",
    "url": "git+ssh://git@bitbucket.org/jangiegb/lirrbits-alexa.git"
  },
  "dependencies": {
    "request": "2.79.0"
  },
  "author": "jangie",
  "license": "ISC",
  "homepage": "https://bitbucket.org/jangiegb/lirrbits-alexa#readme"
}

Credits

Jang-Soo Lee

Jang-Soo Lee

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