Server-Side Shopify Tracking

// Example: Shopify "orders/paid" webhook handler forwarding a
// server-side purchase event to the GA4 Measurement Protocol
import crypto from "crypto";

export async function handleShopifyWebhook(req: Request) {
  const rawBody = await req.text();
  const hmac = req.headers.get("x-shopify-hmac-sha256");
  const digest = crypto
    .createHmac("sha256", process.env.SHOPIFY_WEBHOOK_SECRET!)
    .update(rawBody)
    .digest("base64");

  if (digest !== hmac) {
    return new Response("Invalid signature", { status: 401 });
  }

  const order = JSON.parse(rawBody);

  await fetch(
    `https://www.google-analytics.com/mp/collect?measurement_id=${process.env.GA4_MEASUREMENT_ID}&api_secret=${process.env.GA4_API_SECRET}`,
    {
      method: "POST",
      body: JSON.stringify({
        client_id: order.client_details?.client_id ?? "server-generated",
        events: [{
          name: "purchase",
          params: {
            transaction_id: String(order.id),
            value: parseFloat(order.total_price),
            currency: order.currency,
            items: order.line_items.map((li: any) => ({
              item_id: String(li.product_id),
              item_name: li.title,
              price: parseFloat(li.price),
              quantity: li.quantity,
            })),
          },
        }],
      }),
    }
  );

  return new Response("ok", { status: 200 });
}