worker.js

// UUID generator API (v4).

const CORS_HEADERS = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Methods': 'GET,POST,OPTIONS',
  'Access-Control-Allow-Headers': 'Content-Type',
  'X-Robots-Tag': 'noindex, nofollow'
};

function generateUuid() {
  if (crypto?.randomUUID) {
    return crypto.randomUUID();
  }

  // Fallback for environments without randomUUID.
  const bytes = new Uint8Array(16);
  crypto.getRandomValues(bytes);
  bytes[6] = (bytes[6] & 0x0f) | 0x40;
  bytes[8] = (bytes[8] & 0x3f) | 0x80;
  const hex = [...bytes].map((b) => b.toString(16).padStart(2, '0'));
  return (
    `${hex[0]}${hex[1]}${hex[2]}${hex[3]}` +
    `-${hex[4]}${hex[5]}` +
    `-${hex[6]}${hex[7]}` +
    `-${hex[8]}${hex[9]}` +
    `-${hex[10]}${hex[11]}${hex[12]}${hex[13]}${hex[14]}${hex[15]}`
  );
}

function jsonResponse(data, status = 200) {
  return new Response(JSON.stringify(data), {
    status,
    headers: {
      'Content-Type': 'application/json; charset=utf-8',
      ...CORS_HEADERS
    }
  });
}

function textResponse(text, status = 200) {
  return new Response(text, {
    status,
    headers: {
      'Content-Type': 'text/plain; charset=utf-8',
      ...CORS_HEADERS
    }
  });
}

export default {
  async fetch(request) {
    if (request.method === 'OPTIONS') {
      return new Response(null, { status: 204, headers: CORS_HEADERS });
    }

    const url = new URL(request.url);
    if (url.pathname === '/robots.txt') {
      return textResponse('User-agent: *\nDisallow: /\n');
    }
    if (url.pathname === '/health') {
      return jsonResponse({ status: 'ok' });
    }

    // GET and POST both return a freshly generated UUID.
    const uuid = generateUuid();
    const plain = url.searchParams.get('plain') === '1';
    if (plain) {
      return textResponse(uuid);
    }
    return jsonResponse({ uuid });
  }
};