Rough concept for app recommendation engine powered by Concur Itinerary

ConcurAppRecommendation.js

var express = require('express');
var app = express();

var async = require('async');
var gplay = require('google-play-scraper');
var querystring = require('querystring');
var https = require('https');


app.set('port', (process.env.PORT || 5000));
app.use(express.static(__dirname + '/public'));

app.get('/', function(request, response) {
  //response.send('Hello World!');

  async.waterfall([
    //
	// 1. Call separate service that gets Concur user's trip segments
	//    Check README of https://github.com/ismaelc/Concur-QuickApp
	//    for a live sample data
	//
  	function(callback) {
		var host = "radiant-springs-1767.herokuapp.com";
		var endpoint = "/segments";
		doRequest(host, endpoint, 'GET', {},
			function(concurData) {
				callback(null, concurData);
			});
	},
	//
	// 2. Pick out upcoming segment
	//
	function(concurItinArr, callback) {
		var i = 0;
		var err = null;
		while(i < concurItinArr.length) {
			if(concurItinArr[i].IsNext == "true") break;
			i++;
		}
		if(i >= concurItinArr.length) err = "No upcoming segment.";
		else result = concurItinArr[i].Location;

		callback(err, result);
	},
	//
	// 3. Call google-play-scraper 'search' using segment's city
	//
	function(concurLocation, callback) {
  		gplay.search({
  			term: concurLocation.city,
  			num: 15
  		}).then(function(value) {
  			callback(null, value);
  		}, function(reason) {
  			callback(reason, value);
  		});
	},
	//
	// 4. Display app icons using good 'ol <li> tags
	//
	function(appsArray, callback) {
		callback(null, returnHTMList(appsArray));
	}
  ], function(err, result) {
	    response.send(result);
	 }
  );

});

app.listen(app.get('port'), function() {
  console.log('Node app is running on port', app.get('port'));
});

// UTILS

function doRequest(host, endpoint, method, data, success) {
  var dataString = JSON.stringify(data);
  var headers = {};

  if (method == 'GET') {
    endpoint += '?' + querystring.stringify(data);
  }
  else {
    headers = {
      'Content-Type': 'application/json',
      'Content-Length': dataString.length
    };
  }
  var options = {
    host: host,
    path: endpoint,
    method: method,
    headers: headers
  };

  var req = https.request(options, function(res) {
    res.setEncoding('utf-8');

    var responseString = '';

    res.on('data', function(data) {
      responseString += data;
    });

    res.on('end', function() {
      console.log(responseString);
      var responseObject = JSON.parse(responseString);
      success(responseObject);
    });
  });

  req.write(dataString);
  req.end();
}

function returnHTMList(appsArray) {
	var html = "<ul>";
	for(var i = 0; i < appsArray.length; i++) {
		html += "<li style='display:inline'>" + "<img width='150px' src='" + appsArray[i].icon + "' />" + "</li>"
	}
	html = html + "</ul>";
	return html;
}