traintimesPWA/server/lib/wshandlerv3.js

/**
 *
 * User: Martin Donnelly
 * Date: 2016-09-07
 * Time: 15:33
 *
 */

// from
// https://medium.com/unprogrammer/implementing-publisher-subscriber-pattern-using-javascript-nodejs-and-websockets-82036da7e174

const url = require('url');
const cuid = require('cuid');

const PubSubManager = require('./pubsub');
const logger = require('log4js').getLogger('wshandlerv3');
logger.level = 'debug';

const pubSubManager = new PubSubManager();

function noop() {}

function heartbeat() {
  this.isAlive = true;
}

module.exports = function(events, wsServer) {
  'use strict';

  logger.debug('>> new WS', wsServer);
  wsServer.on('connection', (ws, req) => {
    ws.cuid = cuid();
    console.log(`Connection request for ${ws.cuid}`);

    ws.isAlive = true;
    ws.on('pong', heartbeat);
    
    ws.on('message', (data) => {
      console.log(`data: ${ data}`, this);
      const json = JSON.parse(data);
      const request = json.request;
      const message = json.message;
      const channel = json.channel;

      switch (request) {

        case 'PUBLISH':
          pubSubManager.publish(ws, channel, message);
          break;
        case 'SUBSCRIBE':
          pubSubManager.subscribe(ws, channel);
          break;
      
      }
    });
    ws.on('close', () => {
      console.log('Stopping client connection.', ws.cuid);
      pubSubManager.unsubscribe(ws.cuid);
    });
  });

  const interval = setInterval(function ping() {
    wsServer.clients.forEach(function each(ws) {
      if (ws.isAlive === false) return ws.terminate();

      ws.isAlive = false;
      ws.ping(noop);
    });
  }, 30000);
  
  const sendTweetHandler = (id, obj) => {
    pubSubManager.publishTwitter(id, obj);
  };

  events.on('sendTweet', sendTweetHandler);

  return module;
};