@eventstore.net/event.store/dist/publisher/redis.js

A simple and fast EventStore that support multiple persistence and notification providers

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const connect_1 = require("../redis/connect");
/**
 * A Publisher that use Redis pub / sub feature to message communications.
 */
class RedisPublisher {
    constructor(config) {
        this.listeners = new Map();
        this.listenningRedis = false;
        this.redisSubscriber = connect_1.RedisFactory.createClient(config);
        this.redisPublisher = connect_1.RedisFactory.createClient(config);
    }
    async publish(message) {
        const listeners = await this.redisPublisher.publish(message.stream.aggregation, JSON.stringify(message));
        return listeners > 0;
    }
    async subscribe(aggregation, subscriber) {
        let subscribers = this.listeners.get(aggregation);
        if (!subscribers) {
            subscribers = new Array();
            this.listeners.set(aggregation, subscribers);
        }
        subscribers.push(subscriber);
        await this.redisSubscriber.subscribe(aggregation);
        await this.registerRedisListener();
        return {
            remove: async () => {
                const index = subscribers.indexOf(subscriber);
                subscribers.splice(index, 1);
                if (subscribers.length === 0) {
                    this.redisSubscriber.unsubscribe(aggregation);
                }
            }
        };
    }
    async registerRedisListener() {
        if (!this.listenningRedis) {
            this.listenningRedis = true;
            await this.redisSubscriber.on('message', (aggregation, received) => {
                const message = JSON.parse(received);
                const subscribers = this.listeners.get(aggregation);
                subscribers.forEach(subscriber => subscriber(message));
            });
        }
    }
}
exports.RedisPublisher = RedisPublisher;
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