server.js

const express = require('express');
const dgram = require('dgram');
const bodyParser = require('body-parser');
const DMX = require('dmx');

const dmx = new DMX();
const app = express();
const port = 3000;
const MAXDMX = 20;
const socket = dgram.createSocket('udp4');

app.use(bodyParser.urlencoded({
  extended: true
}))
app.use(bodyParser.json())

// var universe = dmx.addUniverse('App', 'enttec-open-usb-dmx', '/dev/ttyUSB0')
const universe = dmx.addUniverse('demo', 'null', '');

// app.get('/', (req, res) => {
//     return res.send('App is working..');
// });

// app.get('/on', (req, res) => {
//   universe.updateAll(255);
//   return res.send('App is working..');
// });

// app.get('/off', (req, res) => {
//   universe.updateAll(0);
//   return res.send('App is working..');
// });

// const resetUniverse = dmxValues => {
//   for(let i = 0; i < MAXDMX; i+=1) {
//     dmxValues[i] = 0;
//   }
// }

// app.post('/update', (req, res) => {
//     let dmxValues = {};
//     let scenes = req.body['stage'];
//     for(let i = 0; i < scenes.length; i++) {
//       dmxValues[i + 1] = parseInt(scenes[i]);
//     }
//     dmx.update('demo', dmxValues);
//     res.send('Sent to dmx');
// })

socket.on('listening', () => {
  let addr = socket.address();
  console.log(`Listening for UDP packets at ${addr.address}:${addr.port}`);
});

socket.on('error', (err) => {
  console.error(`UDP error: ${err.stack}`);
});

socket.on('message', (msg, rinfo) => {
  let dmxValues = {};
  let jsonMSG = JSON.parse(msg);
  let scenes = jsonMSG['stage'];
  for(let i = 0; i < scenes.length; i++) {
    dmxValues[i + 1] = scenes[i];
  }
  dmx.update('demo', dmxValues);
  // console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});

socket.bind(3001);     // listen for UDP with dgram

app.set('port', 3000); // listen for TCP with Express ??
app.listen(app.get('port'), () => console.log(`Listening on port ${port}`));