------------------  Main.js ------------------


var app = require('express');
var server = require('http').createServer(app);
var io = require('socket.io')(server);
var mysql = require('mysql');
var cluster = require('cluster');
let bodyParser = require('body-parser');
let handle = require('./controllers/apicontroller.js');


///////////////////////////////////////////////////////////////////////////
//Create MySql Connections///
///////////////////////////////////////////////////////////////////////////
var connection = mysql.createPool({
    host: "",
    user: "",
    password: "",
    database: ""
});

if (cluster.isMaster) {

    cluster.fork();
    cluster.fork();
    cluster.on('online', function(worker) {
        console.log('Worker ' + worker.process.pid + ' is online');
    });
    cluster.on('exit', function(worker, code, signal) {
        console.log('Worker ' + worker.process.pid + ' died with code: ' + code + ', and signal: ' + signal);
        console.log('Starting a new worker');
        cluster.fork();
    });

} else {

    ///////////////////////////////////////////////////////////////////////////
    //Handle API Requests///
    ///////////////////////////////////////////////////////////////////////////
    app.use(bodyParser.json());
    app.use(function(req, res, next) {
        res.setHeader('Access-Control-Allow-Origin', '*');
        res.header("Access-Control-Allow-Credentials: true");
        res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
        next();
    });

    app.post('/api/v1/relay', function(request, response) {
            console.log('Worker ' + cluster.worker.id + ': Processing..')

            //check customers subscription
            let key = request.body['public_key']
            let queryingString = 'SELECT * FROM users_app WHERE public_key = ?';

            connection.query(queryingString, [key], function(err, result, fields) {
                if (err) throw err;

                if (request.body['public_key'] !== result[0]['public_key'] ||
                    request.body['private_key'] !== result[0]['private_key'] ||
                    !request.body['channel'] || !request.body['event']) {
                    //log this to a file later get origin for tracking
                    console.log('bad request from: ');
                    return response.sendStatus(400);
                }
                //get the user id of this customers
                var identifier = result[0]['users_app_id'];
                var customer_id = result[0]['user_id'];
                handle.thisRequest(request, response, io, connection,
                    identifier, customer_id, app);
            });
    });

    server.listen(8081, function() {
        console.log('Process ' + process.pid + ' is listening to all incoming requests');
    });

    server.on('close', function() {
        connection.end();
    })
}






------------ API Controller -----------

let limit = require('./ratelimitcontroller.js');

module.exports = {
    thisRequest: function(request, response, io, connection,
                          identifier, customer_id){

      var key            = customer_id;
      var queryingString = 'SELECT * FROM users WHERE id = ?';

      connection.query(queryingString, [key], function(err, result, fields) {
        if (err) throw err;
        switch(result[0]['subscription']) {
              case 'Sandbox':
                  limit.sandboxPlan(request, response, io, connection,
                                  identifier, customer_id);
                  break;
              case 'Small':
                  limit.smallPlan(request, response, io, connection,
                                  identifier, customer_id);
                  break;
              case 'Medium':
                  limit.mediumPlan(request, response, io, connection,
                                  identifier, customer_id);
                  break;
              case 'Large':
                  limit.largePlan(request, response, io, connection,
                                  identifier, customer_id);
                  break;
            }
        });
    }
};


---------- Sandbox ----------
module.exports = {
    sandboxPlan: function(request, response, io, connection, identifier, customer_id){
      var RateLimiter = require('limiter').RateLimiter;
      var limiter = new RateLimiter(3, 'second', true);  // fire CB immediately

      // Immediately send 429 header to client when rate limiting is in effect
      limiter.removeTokens(1, function(err, remainingRequests) {
        if (remainingRequests < 1) {
          console.log('Customer: ' + customer_id + ' has reached their limit.')
          response.writeHead(429, {'Content-Type': 'text/plain;charset=UTF-8'});
          return response.end('429 Too Many Requests - your IP is being rate limited');
        } else {
          //pass the data to the customers front end
          let event = request.body['event'];
          let data = request.body.data;
          io.emit(event, data);

          //let customer know request was successfull
          response.sendStatus(200);

          //track customers usage
          return track.customersMessage(identifier, connection);
        }
      });
    }
}


------------------- useage controller ----------
module.exports = {
    customersMessage: function(identifier, connection){
      var key = identifier;
      var getAppInformation = 'SELECT * FROM users_app_details WHERE users_app_id = ?';

      connection.query(getAppInformation, [key], function(err, result, fields) {
        if (err) throw err;
        let appID    = result[0]['users_app_id'];
        let messageTotal = result[0]['messages_total'] + 1;
        let messageCycle = result[0]['messages_cycle'] + 1;

          var sql = "UPDATE users_app_details set messages_total = ? , messages_cycle = ?  WHERE users_app_id = ?";
          connection.query(sql, [messageTotal, messageCycle, appID], function(err, result) {
            if (err) throw err;
            console.log('processed');
          });
      });
    }
}