JavaScript

Full example for a direct connection to LA⁴ at 192.168.0.23:5000. A server listens for incoming events, a timer sends periodic heartbeats, and the main thread sends commands.

note

This example assumes LA⁴ is reachable at a known static IP. If you are not using a direct or static IP setup, you will need to scan the local network to discover LA⁴'s address before connecting. See the network setup section for details.

const net = require('net');
const crypto = require('crypto');
const readline = require('readline');

class LA4Client {
  static LA4_IP = '192.168.0.23';
  static LA4_PORT = 5000;

  static MY_IP = '192.168.0.100'; // IP of this machine — LA4 will reply here
  static MY_PORT = 5000;          // Port this machine listens on

  static HEARTBEAT_FREQUENCY_SECONDS = 3;
  static SEND_DATA_TIMEOUT_SECONDS = 2;

  static SENDER_NAME = 'My PC App';
  static SENDER_VERSION = '0.1.0';

  constructor() {
    this._senderId = crypto.randomBytes(4).toString('hex');
    this._running = true;
  }

  run() {
    this._startListener();
    this._startHeartbeats();

    // Wait for listener to start before sending commands
    setTimeout(() => {
      this.turnOnModelLight();

      const rl = readline.createInterface({ input: process.stdin });
      console.log('Press Enter to exit...');
      rl.once('line', () => {
        this._running = false;
        rl.close();
        process.exit(0);
      });
    }, 500);
  }

  _send(payload) {
    return new Promise((resolve, reject) => {
      const socket = new net.Socket();
      socket.setTimeout(LA4Client.SEND_DATA_TIMEOUT_SECONDS * 1000);
      socket.connect(LA4Client.LA4_PORT, LA4Client.LA4_IP, () => {
        socket.write(JSON.stringify(payload), 'utf8', () => {
          socket.destroy();
          resolve();
        });
      });
      socket.on('timeout', () => { socket.destroy(); reject(new Error('timeout')); });
      socket.on('error', reject);
    });
  }

  _basePayload() {
    return {
      id: this._senderId,
      name: LA4Client.SENDER_NAME,
      ip: LA4Client.MY_IP,
      port: LA4Client.MY_PORT,
      version: LA4Client.SENDER_VERSION,
      coordinator: true,
    };
  }

  _sendCommand(command) {
    return this._send({ ...this._basePayload(), type_: 'cmd', command });
  }

  turnOnModelLight() {
    const sequence = 'LED_FAN,1\\nMODEL_LIGHT,80';
    const command = `echo "${sequence}" > /home/rigsters/la4_sequence.csv && boardiocli uSeq && boardiocli runSeq`;
    this._sendCommand(command).catch(e => console.error(`Cannot send command - ${e.message}`));
  }

  _startHeartbeats() {
    const tick = () => {
      if (!this._running) return;
      this._send(this._basePayload()).catch(e => {
        if (e.code !== 'ECONNREFUSED' && e.message !== 'timeout') {
          console.error(`Cannot send heartbeat to LA4 - ${e.message}`);
        }
      });
      setTimeout(tick, LA4Client.HEARTBEAT_FREQUENCY_SECONDS * 1000);
    };
    setTimeout(tick, LA4Client.HEARTBEAT_FREQUENCY_SECONDS * 1000);
  }

  _startListener() {
    const server = net.createServer(socket => {
      let data = '';
      socket.setEncoding('utf8');
      socket.on('data', chunk => { data += chunk; });
      socket.on('end', () => {
        if (!data) return;
        let event;
        try {
          event = JSON.parse(data);
        } catch {
          return;
        }
        const name = event.name ?? 'unknown';
        switch (event.type_) {
          case 'output':
            console.log(`[${name}] output: ${event.output}`);
            break;
          case 'message':
            console.log(`[${name}] message: ${event.message}`);
            break;
          case 'unit_info':
            console.log(
              `[${name}] unit info — ` +
              `firmware: ${event.firmware_version}, ` +
              `boardio: ${event.boardio_version}, ` +
              `unit type: ${event.unit_type}`
            );
            break;
        }
      });
    });

    server.listen(LA4Client.MY_PORT, () => {
      console.log(`Listening on port ${LA4Client.MY_PORT}...`);
    });
  }
}

new LA4Client().run();