fix(feeds): self link uses configured domain, not request host

The RSS/Atom/JSON self link was derived from the request origin, leaking
the workers.dev host when reached directly instead of via the custom
domain. Use the configured-domain URL builders so self matches alternate.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/routes/atom.test.ts

@@ -117,10 +117,12 @@ describe("Atom Feed Route", () => {
       expect(body).toContain("Atom Test Feed");
     });
 
-    it("self-link points to atom URL", async () => {
+    it("self-link uses the configured domain, not the request host", async () => {
       const res = await testApp.request(`/${FEED_ID}`, {}, mockEnv);
       const body = await res.text();
-      expect(body).toContain(`/atom/${FEED_ID}`);
+      expect(body).toContain(
+        `rel="self" href="https://${mockEnv.DOMAIN}/atom/${FEED_ID}"`,
+      );
     });
 
     it("Link header advertises hub and self for WebSub discovery", async () => {

src/routes/atom.ts

@@ -38,7 +38,7 @@ export async function handle(c: Context<{ Bindings: Env }>): Promise<Response> {
     }
 
     const base = baseUrl(c.env);
-    const selfUrl = new URL(c.req.url).origin + `/atom/${feedId}`;
+    const selfUrl = feedAtomUrl(feedId, c.env);
     const atomXml = generateAtomFeed(
       feedData.feedConfig,
       feedData.emails,

src/routes/json.test.ts

@@ -52,7 +52,9 @@ describe("JSON Feed Route", () => {
       const res = await testApp.request("/empty-feed", {}, mockEnv);
       const link = res.headers.get("Link") ?? "";
       expect(link).toContain(`rel="hub"`);
-      expect(link).toContain(`rel="self"`);
+      expect(link).toContain(
+        `<https://${mockEnv.DOMAIN}/json/empty-feed>; rel="self"`,
+      );
     });
 
     it("body parses as JSON with jsonfeed version 1.1", async () => {

src/routes/json.ts

@@ -2,7 +2,7 @@ import { Context } from "hono";
 import { Env } from "../types";
 import { generateJsonFeed } from "../infrastructure/feed-generator";
 import { fetchFeedData } from "../application/feed-fetcher";
-import { baseUrl } from "../infrastructure/urls";
+import { baseUrl, feedJsonUrl } from "../infrastructure/urls";
 import { isExpired } from "../domain/feed";
 import { FeedId } from "../domain/value-objects/feed-id";
 
@@ -22,7 +22,7 @@ export async function handle(c: Context<{ Bindings: Env }>): Promise<Response> {
     }
 
     const base = baseUrl(c.env);
-    const selfUrl = new URL(c.req.url).origin + `/json/${feedId}`;
+    const selfUrl = feedJsonUrl(feedId, c.env);
     const jsonFeed = generateJsonFeed(
       feedData.feedConfig,
       feedData.emails,

src/routes/rss.test.ts

@@ -50,7 +50,9 @@ describe("RSS Feed Route", () => {
       const res = await testApp.request("/empty-feed", {}, mockEnv);
       const link = res.headers.get("Link") ?? "";
       expect(link).toContain(`rel="hub"`);
-      expect(link).toContain(`rel="self"`);
+      expect(link).toContain(
+        `<https://${mockEnv.DOMAIN}/rss/empty-feed>; rel="self"`,
+      );
     });
   });
 

src/routes/rss.ts

@@ -38,7 +38,7 @@ export async function handle(c: Context<{ Bindings: Env }>): Promise<Response> {
     }
 
     const base = baseUrl(c.env);
-    const selfUrl = new URL(c.req.url).origin + `/rss/${feedId}`;
+    const selfUrl = feedRssUrl(feedId, c.env);
     const rssXml = generateRssFeed(
       feedData.feedConfig,
       feedData.emails,