andresusandi-pubsub/GoogleSubscriber.js

PubSub library that provides a number of different underlying technologies

const GooglePubSubBase = require('./GooglePubSubBase');
const { name: packageName } = require('./package.json');
const { SUBSCRIPTION_EVENTS } = require('./Constants');

class GoogleSubscriber extends GooglePubSubBase {
    constructor(projectId, keyFilename, topicName, subscriptionName, messageCallback) {
        super(projectId, keyFilename, topicName, subscriptionName);

        if (!messageCallback)
            throw new Error("messageCallback is required");
        
        this.messageCallback = messageCallback;
    }

    beginListening() {
        console.log(`${packageName}/${this.constructor.name} Starting to listen ${SUBSCRIPTION_EVENTS.MESSAGE}`);
        this.subscription.on(SUBSCRIPTION_EVENTS.MESSAGE, this.messageCallback);
    }

    stopListening() {
        console.log(`${packageName}/${this.constructor.name} Stopping to listen ${SUBSCRIPTION_EVENTS.MESSAGE}`);
        this.subscription.removeListener(SUBSCRIPTION_EVENTS.MESSAGE, this.messageCallback);
    }
}

module.exports = GoogleSubscriber;