block-messenger

block-messenger

Simplifies message exchange between pipeline blocks.

Factory Pattern simplifies replacement of Client.

MQTT Client is Implemented based on NPM mqtt package

To Create a MQTT Client using the BlockMessenger Factory

type = 'mqtt'

To receive messages, listen to event 'message' (topic, message) To publish a message, messenger.publish(some_data, callback);

Usage example:

const BlockMessenger = require('block-messenger').BlockMessenger;
const MQTT = require('block-messenger').MQTT;

const bm = new BlockMessenger();

const options = {
    host: '127.0.0.1',
    port: 1883,
    username: 'username,
    password: 'password,
    subscribe_topics: ['some/topic'],
    publish_topics: ['some/topic'],
    use_shared_topics: true,
    group_name: 'group'
};

const mqtt = bm.createMessenger(MQTT, options);

mqtt.on('subscribed', (granted) => {
    console.log(granted);
});

mqtt.on('message', (topic, message) => {
    console.log(`new message in topic ${topic}:`, message.toString());
});

setInterval(() => {
    mqtt.publish('test data', (err) => {
        if (err) {
            console.error(err);
        }
        else {
            console.log('message sent');
        }
    });

}, 1000);

The MQTT Client also emits the following events:

• connect

• reconnect

• close

• offline

• error

• end

• packetsend

• packetreceive

• message

• subscribed

Run Tests

npm test npm run-script test-cov

TO DO:

• Implement kafka-messenger.js (type = 'kafka')