Meta CAPI Setup for Shopify in South Africa.

export interface Env { META_ACCESS_TOKEN: string; META_PIXEL_ID: string; }

async function sha256(str: string) {
  const buf = await crypto.subtle.digest('SHA-256', new TextEncoder().encode(str.trim().toLowerCase()));
  return [...new Uint8Array(buf)].map(b => b.toString(16).padStart(2, '0')).join('');
}

export default {
  async fetch(req: Request, env: Env): Promise<Response> {
    if (req.method !== 'POST') return new Response('Method not allowed', { status: 405 });
    const ev = await req.json<any>();

    const userData: Record<string, unknown> = {
      client_ip_address: req.headers.get('cf-connecting-ip'),
      client_user_agent: req.headers.get('user-agent'),
      fbp: ev.fbp,
      fbc: ev.fbc,
    };
    if (ev.email) userData.em = [await sha256(ev.email)];
    if (ev.phone) userData.ph = [await sha256(ev.phone.replace(/[^0-9]/g, ''))];
    if (ev.country) userData.country = [await sha256(ev.country)];

    const payload = {
      data: [{
        event_name: ev.event_name,
        event_time: Math.floor(Date.now() / 1000),
        event_id: ev.event_id,
        action_source: 'website',
        event_source_url: ev.source_url,
        user_data: userData,
        custom_data: ev.custom_data,
      }],
    };

    const res = await fetch(`https://graph.facebook.com/v19.0/${env.META_PIXEL_ID}/events?access_token=${env.META_ACCESS_TOKEN}`, {
      method: 'POST',
      headers: { 'content-type': 'application/json' },
      body: JSON.stringify(payload),
    });
    return new Response(await res.text(), { status: res.status });
  }
};

analytics.subscribe('checkout_completed', async (event) => {
  const c = event.data.checkout;
  const eventId = crypto.randomUUID();
  const payload = {
    event_name: 'Purchase',
    event_id: eventId,
    source_url: window.location.href,
    fbp: document.cookie.match(/_fbp=([^;]+)/)?.[1],
    fbc: document.cookie.match(/_fbc=([^;]+)/)?.[1],
    email: c.order.customer?.email,
    phone: c.order.customer?.phone,
    country: 'ZA',
    custom_data: {
      currency: c.totalPrice.currencyCode,
      value: Number(c.totalPrice.amount),
      content_ids: c.lineItems.map((li) => li.variant.sku),
      content_type: 'product',
      order_id: c.order.id,
    },
  };
  // Fire CAPI first so the server timestamp leads
  fetch('https://capi.yourstore.co.za/', {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify(payload),
    keepalive: true,
  });
  // Then the client Pixel with the same event_id
  window.fbq && fbq('track', 'Purchase', payload.custom_data, { eventID: eventId });
});