CTA Bus Lookup for API.AI

index.js

/*
 * Copyright (C) 2017 Josh Feinberg
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict';

process.env.DEBUG = 'actions-on-google:*';
const Assistant = require('actions-on-google').ApiAiAssistant;
const http = require("http");

const apiKey = "XXXXXXXXXXXXXXXXX";
const defaultBusStopId = "XXXX";

exports.findBus = (req, res) => {
    const assistant = new Assistant({ request: req, response: res });

    function responseHandler(assistant) {
        var busNumber = assistant.getArgument('busnumber');
        var busDirection = assistant.getArgument('direction').toLowerCase();

        http.get('http://www.ctabustracker.com/bustime/api/v2/getpredictions?key=' + apiKey + '&stpid='+ defaultBusStopId + '&rt=' + busNumber + '&format=json', (res) => {
            res.setEncoding('utf8');
            var rawData = '';
            res.on('data', (chunk) => { rawData += chunk; });
            res.on('end', () => {
                try {
                    parseData(rawData, busNumber, busDirection);
                } catch (e) {
                    assistant.ask("Sorry, I was unable to load bus information. Please try again.")
                    console.error("error: " + e.message);
                }
            });
        })
    }

    /**
     * parses the respond from the API and determines a response
     * @param rawData the raw data from the HTTP response
     * @param busNumber the bus number the user is looking for
     * @param busDirection the bus direction the user is looking for
     */
    function parseData(rawData, busNumber, busDirection) {
        const parsedData = JSON.parse(rawData);
        var response = parsedData['bustime-response'];
        if (response.error != null) {
            noBusses(busNumber);
        }
        var prd = response.prd; // array of preditions
        var predictionsCount = prd.length;
        if (predictionsCount == 0) {
            noBusses(busNumber);
        } else {
            var busFound = findBus(busNumber, busDirection, prd, predictionsCount);
            if (!busFound) {
                noBusses(busNumber);
            }
        }
    }

    /**
     * finds the proper bus and informs the user of the arrival time (in minutes)
     * @param busNumber the bus number the user is looking for
     * @param busDirection the bus direction the user is looking for
     * @param prd the JSON array of predictions
     * @param predictionsCount the amount of predictions that were returned
     * @return if a bus was found
     */
    function findBus(busNumber, busDirection, prd, predictionsCount) {
        var busFound = false;
        for (var i = 0; i < predictionsCount; i++) {
            var routeDirection = prd[i].rtdir.toLowerCase();
            if (routeDirection.localeCompare(busDirection) == 0) {
                var prediction = prd[i].prdctdn;
                if (prediction == "DUE") {
                    assistant.tell("Quick, the " + busNumber + " is here!")
                } else {
                    assistant.ask("<speak>The next <say-as interpret-as=\"cardinal\">" + busNumber + "</say-as> will arrive in " + prd[i].prdctdn + " minutes. Would you like to find another?</speak>")
                }
                busFound = true;
                break;
            }
        }
        return busFound;

    }

    /**
     * alerts that no busses were found and asks if the user would like a different route
     * @param busNumber the bus number the user is looking for
     */
    function noBusses(busNumber) {
        assistant.ask("<speak>It does not appear there are any <say-as interpret-as=\"cardinal\">" + busNumber + "</say-as> buses on the way, would you like to try another route?</speak>")
    }

    const actionMap = new Map();
    actionMap.set('bus-requested', responseHandler);
    assistant.handleRequest(actionMap);
};

package.json

{
  "name": "get-cta-bus",
  "version": "1.0.0",
  "description": "API.AI Bus Lookup",
  "author": "Josh Feinberg <josh@joshafeinberg.com>",
  "license": "Apache-2.0",
  "dependencies": {
    "actions-on-google": "^1.0.9"
  }
}