fix(thank-you): serve GiroCode as signed PNG URL instead of data URL

app/routes/api.public.girocode[.png].tsx

@@ -0,0 +1,84 @@
+import type { LoaderFunctionArgs } from "react-router";
+import { unauthenticated } from "../shopify.server";
+import db from "../db.server";
+import { buildGiroCodePngBuffer } from "../services/invoice/girocode";
+import { verifyGiroCodeUrl } from "../services/invoice/signedUrl";
+
+/**
+ * Public PNG endpoint that returns the GiroCode QR image bytes for an order.
+ * Auth: short-lived HMAC-signed URL (issued by /api/public/payment-info).
+ *
+ * Required query params: shop, orderId, exp, sig.
+ */
+export const loader = async ({ request }: LoaderFunctionArgs) => {
+  const url = new URL(request.url);
+  const verified = verifyGiroCodeUrl(url.searchParams);
+  if (!verified.ok) {
+    return new Response(`unauthorized: ${verified.reason ?? "invalid"}`, { status: 401 });
+  }
+  const { shop, orderId } = verified;
+  if (!shop || !orderId) {
+    return new Response("bad request", { status: 400 });
+  }
+
+  const settings = await db.shopSettings.findUnique({ where: { shopDomain: shop } });
+  if (!settings?.iban) {
+    return new Response("not found", { status: 404 });
+  }
+
+  // Recompute payload server-side from order + settings (don't trust client).
+  const numericId = orderId.replace(/[^0-9]/g, "");
+  const orderGid = `gid://shopify/Order/${numericId}`;
+
+  const { admin } = await unauthenticated.admin(shop);
+  const res = await admin.graphql(
+    `#graphql
+    query GiroCodeOrderInfo($id: ID!) {
+      order(id: $id) {
+        name
+        currencyCode
+        totalPriceSet { shopMoney { amount } }
+        totalOutstandingSet { shopMoney { amount } }
+      }
+    }`,
+    { variables: { id: orderGid } },
+  );
+  const json = (await res.json()) as {
+    data?: {
+      order?: {
+        name?: string;
+        currencyCode?: string;
+        totalPriceSet?: { shopMoney: { amount: string } };
+        totalOutstandingSet?: { shopMoney: { amount: string } };
+      } | null;
+    };
+  };
+  const o = json.data?.order;
+  if (!o) {
+    return new Response("not found", { status: 404 });
+  }
+
+  const total = parseFloat(o.totalPriceSet?.shopMoney.amount ?? "0");
+  const outstanding = parseFloat(o.totalOutstandingSet?.shopMoney.amount ?? "0");
+  const amount = outstanding > 0 ? outstanding : total;
+  const remittance = o.name ?? numericId;
+
+  const png = await buildGiroCodePngBuffer({
+    beneficiaryName: [settings.companyName, settings.legalForm].filter(Boolean).join(" "),
+    iban: settings.iban,
+    bic: settings.bic,
+    amount,
+    currency: o.currencyCode ?? "EUR",
+    remittance,
+  });
+
+  const body = new Uint8Array(png);
+  return new Response(body, {
+    status: 200,
+    headers: {
+      "Content-Type": "image/png",
+      "Cache-Control": "private, max-age=300",
+      "Access-Control-Allow-Origin": "*",
+    },
+  });
+};