Integración con el motor de reservas

El iframe pide al cargador un cálculo o retención; el cargador llama a tu servidor del mismo origen con la cookie de sesión de reserva. Ambos verifican el origen y la ventana del mensaje. Tu proxy solo acepta un entero de puntos para retener, rechaza identidad y URL del cliente, limita el crédito según el carrito de referencia e impide que las respuestas se guarden en cachés compartidas.

// Run ONLY on your booking engine's server (Web Request/Response, Node 20+).
// Implement the required adapters using your existing guest auth and cart store.
function createCreditProxy({ partnerOrigin, getVerifiedBookingContext,
  getTenantApiKey, withBookingLock, saveCreditIntent, saveCreditHold,
  fetchImpl = fetch }) {
  const reply = (status, data) => Response.json(data, { status,
    headers: { 'Cache-Control': 'private, no-store', 'Pragma': 'no-cache', 'Vary': 'Cookie' } });
  const fail = (status, message) => reply(status, { error: { message } });
  // Match GuestMaker's pointsToAmount: decimal stabilization and half-to-even cents.
  const pointsMinor = (points, rate) => {
    const value = Number((points / rate * 100).toFixed(10));
    const floor = Math.floor(value), fraction = value - floor;
    return fraction > 0.5 ? floor + 1 : fraction < 0.5 ? floor : floor % 2 === 0 ? floor : floor + 1;
  };
  const validContext = (c) => c && typeof c.tenantId === 'string' &&
    typeof c.cartId === 'string' && typeof c.memberEmail === 'string' &&
    c.memberEmail.length <= 254 && c.memberEmail.includes('@') &&
    Number.isSafeInteger(c.totalMinor) && c.totalMinor > 0 && c.totalMinor <= 100000000 &&
    /^[A-Z]{3}$/.test(c.currency) && typeof c.creditReferenceId === 'string' &&
    c.creditReferenceId.length > 0 && c.creditReferenceId.length <= 200;

  return async function handle(request) {
    const url = new URL(request.url);
    const isQuote = request.method === 'GET' && url.pathname === '/api/guestmaker-credit/quote';
    const isHold = request.method === 'POST' && url.pathname === '/api/guestmaker-credit/hold';
    if (url.origin !== partnerOrigin || url.search || (!isQuote && !isHold))
      return fail(404, 'Unknown credit operation');
    const site = request.headers.get('sec-fetch-site');
    const origin = request.headers.get('origin');
    if ((site && site !== 'same-origin') || (origin && origin !== partnerOrigin) ||
        (isHold && origin !== partnerOrigin) || (isQuote && site !== 'same-origin'))
      return fail(403, 'Same-origin booking request required');
    let points;
    if (isHold) {
      if (request.headers.get('content-type')?.split(';')[0].trim() !== 'application/json')
        return fail(415, 'JSON required');
      const reader = request.body?.getReader();
      if (!reader) return fail(400, 'Points required');
      const decoder = new TextDecoder();
      let text = '', bytes = 0;
      while (true) {
        const chunk = await reader.read();
        if (chunk.done) break;
        bytes += chunk.value.byteLength;
        if (bytes > 1024) { await reader.cancel(); return fail(413, 'Body too large'); }
        text += decoder.decode(chunk.value, { stream: true });
      }
      let body;
      try { body = JSON.parse(text + decoder.decode()); } catch { return fail(400, 'Invalid JSON'); }
      if (!body || Array.isArray(body) || Object.keys(body).join(',') !== 'points' ||
          !Number.isSafeInteger(body.points) || body.points < 1 || body.points > 100000000)
        return fail(400, 'Only positive integer points are accepted');
      points = body.points;
    }

    // Verify the guest's session AND cart ownership. Load tenant/member/cart
    // values from your server, never browser parameters, email or hold IDs.
    const verified = await getVerifiedBookingContext(request);
    if (!validContext(verified)) return fail(401, 'Verified guest booking required');
    try {
      return await withBookingLock(verified.cartId, async () => {
        // Re-read under a durable, cross-process cart lock shared with checkout.
        const c = await getVerifiedBookingContext(request);
        if (!validContext(c) || c.cartId !== verified.cartId || c.tenantId !== verified.tenantId ||
            c.memberEmail !== verified.memberEmail) return fail(401, 'Booking session changed');
        const key = await getTenantApiKey(c.tenantId); // server-only tenant-key lookup
        const signal = AbortSignal.any([request.signal, AbortSignal.timeout(12000)]);
        const upstream = async (operation, body) => {
          const endpoint = new URL('https://www.guestmaker.ai/api/v1/loyalty/credit/' + operation);
          if (operation === 'quote') endpoint.search = new URLSearchParams({
            surface: 'booking_direct', email: c.memberEmail, currency: c.currency,
            max_amount: String(c.totalMinor / 100) }).toString();
          const response = await fetchImpl(endpoint.toString(), {
            method: operation === 'quote' ? 'GET' : 'POST', cache: 'no-store', redirect: 'error', signal,
            headers: { Authorization: 'Bearer ' + key, 'Content-Type': 'application/json' },
            ...(body ? { body: JSON.stringify(body) } : {}) });
          if (!response.ok) throw new Error('Credit service rejected the operation');
          return (await response.json()).data;
        };
        if (!isHold || !c.creditIntent) {
          const q = await upstream('quote');
          if (!isHold) {
            // Return only widget fields; omit member identifiers and other holds.
            const data = {};
            for (const field of ['surface_enabled', 'spendable_points', 'redemption_rate', 'currency',
              'max_amount', 'max_points', 'min_points', 'step_points', 'presets']) data[field] = q[field];
            return reply(200, { success: true, data });
          }
          if (!q.surface_enabled || q.currency !== c.currency || !Number.isFinite(q.redemption_rate) ||
              q.redemption_rate <= 0 || points < q.min_points || points > q.max_points ||
              !Number.isSafeInteger(q.step_points) || q.step_points < 1 || points % q.step_points !== 0 ||
              pointsMinor(points, q.redemption_rate) < 1 || pointsMinor(points, q.redemption_rate) > c.totalMinor)
            return fail(422, 'Credit exceeds the server booking quote');
          // Persist BEFORE calling hold. An uncertain response retries the same intent.
          c.creditIntent = { points, currency: c.currency, referenceId: c.creditReferenceId,
            amountMinor: pointsMinor(points, q.redemption_rate),
            tenantId: c.tenantId, memberEmail: c.memberEmail, cartId: c.cartId };
          await saveCreditIntent(c, c.creditIntent);
        }
        const intent = c.creditIntent;
        if (intent.points !== points || intent.currency !== c.currency ||
            intent.referenceId !== c.creditReferenceId || intent.amountMinor > c.totalMinor ||
            intent.tenantId !== c.tenantId || intent.memberEmail !== c.memberEmail || intent.cartId !== c.cartId)
          return fail(409, 'Booking credit intent changed; reconcile before retrying');
        const hold = await upstream('hold', { email: c.memberEmail, surface: 'booking_direct',
          channel: 'website', currency: c.currency, external_reference_id: intent.referenceId, points });
        if (hold.points !== points || hold.currency !== c.currency ||
            Math.round(hold.amount_value * 100) !== intent.amountMinor ||
            hold.status !== 'active' || !(Date.parse(hold.expires_at) > Date.now()))
          return fail(502, 'Hold differs from the saved booking intent');
        await saveCreditHold(c, hold);
        return reply(200, { success: true, data: { ...hold, external_reference_id: intent.referenceId } });
      });
    } catch { return fail(502, 'Credit unavailable; retry the same booking intent'); }
  };
}

// In YOUR server's /api/guestmaker-credit/quote and /hold routes:
const handle = createCreditProxy({
  partnerOrigin: 'https://booking.example.com',
  getVerifiedBookingContext, // your verified guest-session + authorized cart lookup
  getTenantApiKey,           // your server secret store, indexed by verified tenant
  withBookingLock,           // your durable cart lock shared with checkout/cancellation
  saveCreditIntent,          // your durable cart write before the upstream hold
  saveCreditHold,            // your durable cart write used for server-side pricing
});
// Next.js route handlers can export GET = handle and POST = handle.
// No GuestMaker endpoint implements this partner-owned proxy for you.

El adaptador de contexto debe verificar la sesión del huésped y la titularidad del carrito y devolver tenantId, cartId, memberEmail, totalMinor (céntimos enteros para este ejemplo EUR), currency y un creditReferenceId estable creado en el servidor. También carga cualquier creditIntent guardado. Bloquea conjuntamente los cambios de precios, retención, compra y cancelación del carrito; conserva la intención y la retención de forma persistente para que los reintentos usen el mismo socio, puntos y referencia. Limita estas rutas a tu origen de reservas, aplica límites por sesión y asegúrate de que el service worker no intercepte solicitudes privadas de API. La API de GuestMaker no verifica por ti la sesión del huésped. El ejemplo usa el canal website, que debe estar activado para crédito monetario.

Las inserciones antiguas basadas en claves siguen siendo compatibles durante la migración, pero no se admiten para nuevas integraciones públicas. Sustitúyelas por el modo proxy y elimina la clave del navegador. Si se expuso una clave privada, su propietario debe sustituirla después de migrar las integraciones dependientes; no rotes credenciales ajenas automáticamente.