socket.js

const socketio = require('socket.io');
const socketioJwt = require('socketio-jwt');
const Sensors = require('./models/Sensor')
var ObjectId = require('mongoose').Types.ObjectId;

module.exports.listen = function (app) {
    var io = socketio.listen(app);

    io.on('connection', socketioJwt.authorize({
        secret: process.env.CLIENT_SECRET,
        timeout: 15000 // 15 seconds to send the authentication message
    }))
	.on('authenticated', function (socket) {
	    console.log('connected & authenticated: ' + JSON.stringify(socket.decoded_token));

	    socket.on('sensor', function (msg) {
	        var userData = socket.decoded_token;
	        var sensorData = JSON.parse(msg);

	        //we can save the data sent through the socket using userData.id to identify the user

	        //save data 
	        console.log(userData.id);
	        console.log(new ObjectId(userData.id));
	        Sensors.findOne({ userId: new ObjectId(userData.id) }, function (err, sensor) {
	            if (err) throw err;

	            if (sensor) {
	                console.log('Sensor found');
	                sensor.updateData(sensorData);
	            }
	            else {
	                console.log('Invalid Sensor');
	            }

	        });

	    });
	})
    
    return io;
}