app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var index = require('./routes/index');
var users = require('./routes/users');
var request = require('request');
var googleTTS = require('google-tts-api');

var app = express();

var http = require('http').createServer(app);
var fs = require('fs');
var socketio = require('socket.io');
var request = require('request');
var io = socketio();
app.io = io;

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'hjs');

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
    extended: false
}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', index);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
    var err = new Error('Not Found');
    err.status = 404;
    next(err);
});

// error handler
app.use(function(err, req, res, next) {
    // set locals, only providing error in development
    res.locals.message = err.message;
    res.locals.error = req.app.get('env') === 'development' ? err : {};

    // render the error page
    res.status(err.status || 500);
    res.render('error');
});

io.on('connection', function(socket) {

    console.log("Got connection.");

    socket.on('query', function(q) {
        console.log(q);
        wolframQuery(q, socket);
    });
});

function wolframQuery(query, socket, url) {
    var result;
    var timeout = 4; // How many seconds to wait before sending failure message
    var completed = false;
    var failedQueryResponse = "Ignorant human. Next time ask me a question that actually makes sense.";
    var options = {
        url: 'https://api.wolframalpha.com/v1/result?appid=XVVT6H-237WH8JWQY&i=' + encodeURI(query),
        headers: {}
    };

    function callback(error, response, body) {

        // Handle successful response
        if (!error && response.statusCode == 200) {
            completed = true;
            getAudioURL(body).then(function(url) {
                socket.emit('message', {
                    stuff: body,
                    audioURL: url,
                    success: false
                });
                console.log(body);
            });
        }

        // Deal with failure
        setTimeout(function() {
            if (completed == false) {
                getAudioURL(failedQueryResponse).then(function(url) {
                    socket.emit('message', {
                        stuff: failedQueryResponse,
                        audioURL: url,
                        success: false
                    });
                    console.log('Request failed. Sending: ' + failedQueryResponse);
                });
            }
        }, timeout * 1000);
    }

    request(options, callback);
}

function getAudioURL(text) {
    return new Promise(function(resolve, reject) {

        googleTTS(text, 'en', 1) // Speed = 1
            .then(function(url) {
                console.log(url);
                resolve(url);
            })
            .catch(function(err) {
                console.error(err.stack);
                reject("Could not retrieve audio URL.");
            });
    });
}

module.exports = app;