node-red-contrib-minelert-universal-io/gateway.js

Node-RED nodes for Universal IO Gateway and I/O Modules

const mqtt = require('mqtt');
const { EventBus, logInfo } = require('@minelert-smartlink/common');

module.exports = function (RED) {
  function GatewayNode(config) {
    RED.nodes.createNode(this, config);
    const node = this;

    // Load config
    const mqttHost = config.mqttHost || 'mqtt://localhost';
    const sensorEventTopic = 'smartlink/sensors/+/event';
    const ioChannelEventTopic = 'smartlink/io/+/+/channel/+';

    // MQTT setup
    const mqttClient = mqtt.connect(mqttHost);

    // this.listeners = [];
    // this.registerListener = (cb) => this.listeners.push(cb);

    mqttClient.on('connect', () => {
      node.log('MQTT connected');
      mqttClient.subscribe(sensorEventTopic, (err) => {
        if (err) node.error(`MQTT subscribe error: ${err.message}`);
        else node.log(`Subscribed to MQTT topic: ${sensorEventTopic}`);
      });
      mqttClient.subscribe(ioChannelEventTopic, (err) => {
        if (err) node.error(`MQTT subscribe error: ${err.message}`);
        else node.log(`Subscribed to MQTT topic: ${ioChannelEventTopic}`);
      });
    });

    mqttClient.on('message', (topic, message) => {
      const payloadStr = message.toString();
      try {
        const payload = JSON.parse(payloadStr);
        node.log(JSON.stringify(payload))
      if (topic.startsWith("smartlink/sensors/")) {
        const topicArr = topic.split('/')
        const id = topicArr[2]
        EventBus.emit('sensor-event', payload);
      } else if (topic.startsWith("smartlink/io/")) {
        const topicArr = topic.split('/')
        const id = topicArr[2]
        const ioType = topicArr[3]
        const channel = Number(topicArr[5])
        EventBus.emit('io-channel-event', {moduleId: id, ioType: ioType, channel: channel, value: payload.value});
      }

         
      } catch (err) {
        node.error(`Invalid MQTT JSON: ${err.message}`);
      }
    });

    mqttClient.on('error', (err) => {
      node.error(`MQTT error: ${err.message}`);
    });

    // Send command over mqtt (from within Node-RED or EventBus)
    function sendCommand(msg) {
      const { topic, command } = msg
      console.log(topic, command)
      // node.log(`Sending ${msg.topic}: ${msg.command}`);
      mqttClient.publish(topic, JSON.stringify(command))
    }

    node.sendCommand = sendCommand;

    EventBus.on('send-command', sendCommand);

    // Cleanup on node shutdown
    node.on('close', (removed, done) => {
      node.log('Closing Gateway node...');
      EventBus.off("send-command", sendCommand);
      
      if (mqttClient.connected) mqttClient.end();

      done();
    });
  }

  RED.nodes.registerType('gateway', GatewayNode);
};