NodeBB/NodeBB

'use strict';

const nconf = require('nconf');
const util = require('util');
const winston = require('winston');
const { EventEmitter } = require('events');
const connection = require('./connection');

let channelName;
const PubSub = function () {
    const self = this;
    channelName = `db:${nconf.get('redis:database')}:pubsub_channel`;
    self.queue = [];
    connection.connect().then((client) => {
        self.subClient = client;
        self.subClient.subscribe(channelName);
        self.subClient.on('message', (channel, message) => {
            if (channel !== channelName) {
                return;
            }

            try {
                const msg = JSON.parse(message);
                self.emit(msg.event, msg.data);
            } catch (err) {
                winston.error(err.stack);
            }
        });
    });

    connection.connect().then((client) => {
        self.pubClient = client;
        self.queue.forEach(payload => client.publish(channelName, payload));
        self.queue.length = 0;
    });
};

util.inherits(PubSub, EventEmitter);

PubSub.prototype.publish = function (event, data) {
    const payload = JSON.stringify({ event: event, data: data });
    if (this.pubClient) {
        this.pubClient.publish(channelName, payload);
    } else {
        this.queue.push(payload);
    }
};

module.exports = new PubSub();