The hub record advertises its public base, not localhost

src/lib/openswarm/openswarm.test.ts

@@ -246,3 +246,21 @@ describe('the README renderer', () => {
     expect(escapeHtml(`<&>"'`)).toBe('&lt;&amp;&gt;&quot;&#39;');
   });
 });
+
+describe('the hub record', () => {
+  it('advertises the public base, not whatever origin the proxy handed it', async () => {
+    // Behind Railway the request origin is internal, and a record built from
+    // it told every client to call back on localhost.
+    const { publicOrigin } = await import('./service');
+    const previous = process.env.NEXT_PUBLIC_APP_URL;
+
+    process.env.NEXT_PUBLIC_APP_URL = 'https://bittorrented.com/';
+    expect(publicOrigin('https://localhost:3000')).toBe('https://bittorrented.com');
+
+    delete process.env.NEXT_PUBLIC_APP_URL;
+    expect(publicOrigin('http://localhost:3000')).toBe('http://localhost:3000');
+
+    if (previous === undefined) delete process.env.NEXT_PUBLIC_APP_URL;
+    else process.env.NEXT_PUBLIC_APP_URL = previous;
+  });
+});

src/lib/openswarm/service.ts

@@ -890,8 +890,21 @@ export function hubKey(): string {
   return isKey(key) ? key : 'ed25519:0000000000000000000000000000000000000000000000000000000000000000';
 }
 
+/**
+ * The public base a client should call back on.
+ *
+ * Behind Railway's proxy the request's own origin is the internal one, so a
+ * record built from it told everybody to talk to localhost. The configured app
+ * URL wins, exactly as the seedbox and IPTV rails already do it, and the
+ * request origin is only the fallback for a local run.
+ */
+export function publicOrigin(fallbackOrigin?: string): string {
+  return (process.env.NEXT_PUBLIC_APP_URL || fallbackOrigin || 'https://bittorrented.com').replace(/\/+$/, '');
+}
+
 /** `GET /.well-known/openswarm-hub.json` (ippay §5.1, pay2seed §6.1). */
-export function hubRecord(origin: string): Record<string, unknown> {
+export function hubRecord(requestOrigin: string): Record<string, unknown> {
+  const origin = publicOrigin(requestOrigin);
   return {
     openswarm: OPENSWARM_VERSION,
     type: 'ippay.hub',