move changes to other pr

apps/login/next-env-vars.d.ts

@@ -14,6 +14,14 @@ declare namespace NodeJS {
      */
     ZITADEL_API_URL: string;
 
+    /**
+     * Takes effect only if ZITADEL_API_URL is not empty.
+     * This is only relevant if Zitadels runtime has the ZITADEL_INSTANCEHOSTHEADERS config changed.
+     * The default is x-zitadel-instance-host.
+     * Most users don't need to set this variable.
+     */
+    ZITADEL_INSTANCE_HOST_HEADER: string;
+
     /**
      * Self hosting: The service user id
      */

apps/login/src/lib/service.ts

@@ -42,8 +42,26 @@ export async function createServiceForHost<T extends ServiceClass>(
     throw new Error("No token found");
   }
 
+  const instanceHost = new URL(serviceUrl).host;
   const transport = createServerTransport(token, {
-    baseUrl: serviceUrl,
+    baseUrl: process.env.ZITADEL_API_URL ?? serviceUrl,
+    interceptors:
+      (process.env.ZITADEL_API_URL &&
+        process.env.ZITADEL_API_URL != serviceUrl) ||
+      process.env.ZITADEL_INSTANCE_HOST_HEADER
+        ? [
+            (next) => {
+              return (req) => {
+                req.header.set(
+                  process.env.ZITADEL_INSTANCE_HOST_HEADER ??
+                    "x-zitadel-instance-host",
+                  instanceHost,
+                );
+                return next(req);
+              };
+            },
+          ]
+        : undefined,
   });
 
   return createClientFor<T>(service)(transport);