visitor-signin/scripts/printer-status.mjs

/**
 * Asks the printer what it actually has loaded, and what it is complaining about.
 *
 *   docker compose exec visitor-signin node scripts/printer-status.mjs
 *   docker compose exec visitor-signin node scripts/printer-status.mjs --host 10.0.0.5
 *
 * brother_ql's network backend only writes to the socket; it never reads, which is
 * why a refused job still looks like a success. The Brother raster protocol has a
 * status request that returns a 32 byte block describing the media in the machine
 * and any error, so we ask directly.
 */
import net from 'node:net';
import db from '../src/db.js';

function arg(name, fallback = null) {
  const i = process.argv.indexOf(`--${name}`);
  return i > -1 && process.argv[i + 1] && !process.argv[i + 1].startsWith('--')
    ? process.argv[i + 1]
    : fallback;
}

const site = arg('site')
  ? db.prepare('SELECT * FROM sites WHERE id = ?').get(Number(arg('site')))
  : db.prepare('SELECT * FROM sites WHERE printer_host IS NOT NULL ORDER BY id LIMIT 1').get();

const host = arg('host', site?.printer_host);
const port = Number(arg('port', site?.printer_port || 9100));

if (!host) {
  console.error('No printer address. Set one in Admin -> Sites, or pass --host.');
  process.exit(1);
}

/* ------------------------------------------------------------- decoding */

const MEDIA_TYPES = {
  0x00: 'no media loaded',
  0x0a: 'continuous roll',
  0x0b: 'die-cut labels',
  0x4a: 'continuous roll (cleaning)',
  0x4b: 'die-cut labels (cleaning)',
};

const ERRORS_1 = [
  [0x01, 'no media loaded'],
  [0x02, 'end of media'],
  [0x04, 'cutter jam'],
  [0x08, 'weak batteries'],
  [0x10, 'printer in use'],
  [0x80, 'printer turned off'],
];

const ERRORS_2 = [
  [0x01, 'wrong media — the job does not match the roll that is loaded'],
  [0x04, 'expansion buffer full'],
  [0x08, 'communication error'],
  [0x10, 'communication buffer full'],
  [0x20, 'cover is open'],
  [0x40, 'cancel key pressed'],
  [0x80, 'media cannot be fed'],
];

function decode(buf) {
  if (buf.length < 32) return { error: `Short reply (${buf.length} bytes).` };
  const mediaWidth = buf[10];
  const mediaType = buf[11];
  const mediaLength = buf[17];
  return {
    mediaWidthMm: mediaWidth,
    mediaLengthMm: mediaLength,
    mediaType: MEDIA_TYPES[mediaType] || `unknown (0x${mediaType.toString(16)})`,
    mediaTypeRaw: mediaType,
    errors: [
      ...ERRORS_1.filter(([bit]) => buf[8] & bit).map(([, text]) => text),
      ...ERRORS_2.filter(([bit]) => buf[9] & bit).map(([, text]) => text),
    ],
    raw: buf.subarray(0, 32).toString('hex').replace(/(..)/g, '$1 ').trim(),
  };
}

/** The label id brother_ql should be given, worked out from what is loaded. */
function suggestLabel(status) {
  if (status.mediaTypeRaw === 0x00) return null;
  const continuous = status.mediaTypeRaw === 0x0a || status.mediaTypeRaw === 0x4a;
  if (continuous) {
    return String(status.mediaWidthMm); // 62, 29, 12 ...
  }
  return status.mediaLengthMm
    ? `${status.mediaWidthMm}x${status.mediaLengthMm}`
    : `${status.mediaWidthMm} (die-cut, length unknown)`;
}

/* --------------------------------------------------------------- asking */

console.log(`\n  Asking ${host}:${port} what it has loaded...\n`);

const socket = net.createConnection({ host, port, timeout: 8000 });
const chunks = [];

socket.on('connect', () => {
  // 200 null bytes clears any half-finished job, then initialise, then ask.
  socket.write(Buffer.alloc(200, 0x00));
  socket.write(Buffer.from([0x1b, 0x40]));
  socket.write(Buffer.from([0x1b, 0x69, 0x53]));

  // Some firmware only answers once it is in raster mode, so ask again that way
  // before giving up.
  setTimeout(() => {
    if (!chunks.length && !socket.destroyed) {
      socket.write(Buffer.from([0x1b, 0x69, 0x61, 0x01]));
      socket.write(Buffer.from([0x1b, 0x69, 0x53]));
    }
  }, 1500);
});

socket.on('data', (d) => {
  chunks.push(d);
  if (Buffer.concat(chunks).length >= 32) socket.end();
});

socket.on('timeout', () => {
  socket.destroy();
  if (!chunks.length) {
    console.error('  The printer accepted the connection but sent nothing back.');
    console.error('');
    console.error('  Many Brother network print servers are write-only on port 9100: they accept');
    console.error('  jobs but never report status, even though the same printer answers happily');
    console.error('  over USB. If this is one of them, no amount of asking will help.');
    console.error('');
    console.error('  Read the printer instead from:');
    console.error('    - the display on the machine itself');
    console.error('    - Brother Status Monitor, on a PC with the printer installed');
    console.error('    - the printer\'s own web page, at http://' + host + '/');
    console.error('');
    console.error('  Status Monitor in particular gives the exact reason a job was refused,');
    console.error('  which is more than brother_ql can tell you — its network backend never');
    console.error('  reads the socket, so it reports success whatever the printer does.');
    console.error('');
    process.exit(1);
  }
});

socket.on('error', (err) => {
  console.error(`  Could not reach it: ${err.message}\n`);
  process.exit(1);
});

socket.on('close', () => {
  const buf = Buffer.concat(chunks);
  if (!buf.length) process.exit(1);

  const status = decode(buf);
  if (status.error) {
    console.error(`  ${status.error}\n  raw: ${buf.toString('hex')}\n`);
    process.exit(1);
  }

  console.log(`  media loaded    ${status.mediaWidthMm} mm ${status.mediaType}`);
  if (status.mediaLengthMm) console.log(`  label length    ${status.mediaLengthMm} mm`);
  console.log(`  errors          ${status.errors.length ? status.errors.join('; ') : 'none reported'}`);
  console.log(`  raw status      ${status.raw}`);

  const suggested = suggestLabel(status);
  console.log('');
  if (!suggested) {
    console.log('  No media detected. Open and close the cover to make it re-read the roll.');
  } else {
    console.log(`  Use this roll id:  --label ${suggested}`);
    console.log(`  Try it with:       node scripts/print-test.mjs --label ${suggested}`);
  }
  console.log('');
});