traintimesPWA/server/lib/pubsub.js

const logger = require('log4js').getLogger('pubsub');

logger.level = 'debug';

class PubSubManager {
  constructor() {
    this.channels = {
      'twitter': {

      },
      'weather': {
        'message': '',
        'subscribers': []
      },
      'sports': {
        'message': '',
        'subscribers': []
      }
    };
    this.brokerId = setInterval(() => {
      this.broker(); 
    }, 1000);
  }
  subscribe(subscriber, channel) {
    const channelSplit = channel.split('-');

    if (channelSplit[0] === 't') {

      if (!this.channels.twitter.hasOwnProperty(channel)) 
        this.channels.twitter[channel] = {
          'message': null,
          'subscribers': []
        };

      logger.info(`subscribing to ${channel}`);

      this.channels.twitter[channel].subscribers.push(subscriber);
    }
  }

  removeBroker() {
    clearInterval(this.brokerId);
  }

  publish(publisher, channel, message) {
    this.channels[channel].message = message;
  }

  publishTwitter( channel, message) {
    logger.debug('Publish:', channel, message);

    if (!this.channels.twitter.hasOwnProperty(channel))
      this.channels.twitter[channel] = {
        'message': null,
        'subscribers': []
      };

    this.channels.twitter[channel].message = message;
  }

  broker() {
    // logger.debug('Broker...');
    for (const channel in this.channels.twitter) 
      // logger.debug(channel);
      if (this.channels.twitter.hasOwnProperty(channel)) {
        const channelObj = this.channels.twitter[channel];
        if (channelObj.message) {
          console.log(`found message: ${channelObj.message} in ${channel}`);

          channelObj.subscribers.forEach(subscriber => {
            subscriber.send(JSON.stringify({
              'message': channelObj.message
            }));
          });

          channelObj.message = '';
        }
      }

    /*    for (const channel in this.channels)
      if (this.channels.hasOwnProperty(channel)) {
        const channelObj = this.channels[channel];
        if (channelObj.message) {
          console.log(`found message: ${channelObj.message} in ${channel}`);

          channelObj.subscribers.forEach(subscriber => {
            subscriber.send(JSON.stringify({
              'message': channelObj.message
            }));
          });

          channelObj.message = '';
        }
      }*/
  }
}
module.exports = PubSubManager;