fix: route all Pages hostnames through Cloudflare Access

public/_worker.js

@@ -0,0 +1,15 @@
+const CANONICAL_HOST = 'auto-research-private.pages.dev';
+
+export default {
+  async fetch(request, env) {
+    const url = new URL(request.url);
+
+    if (url.hostname !== CANONICAL_HOST) {
+      url.protocol = 'https:';
+      url.host = CANONICAL_HOST;
+      return Response.redirect(url.toString(), 307);
+    }
+
+    return env.ASSETS.fetch(request);
+  },
+};

tests/pages-access-guard.test.mjs

@@ -0,0 +1,28 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import worker from '../public/_worker.js';
+
+const canonical = 'auto-research-private.pages.dev';
+
+function assets() {
+  return {
+    ASSETS: {
+      fetch: async (request) => new Response(`asset:${new URL(request.url).pathname}`),
+    },
+  };
+}
+
+test('canonical Pages hostname serves the requested static asset', async () => {
+  const response = await worker.fetch(new Request(`https://${canonical}/journal/2.json`), assets());
+  assert.equal(response.status, 200);
+  assert.equal(await response.text(), 'asset:/journal/2.json');
+});
+
+test('deployment and branch hostnames redirect through the Access-protected canonical hostname', async () => {
+  const response = await worker.fetch(
+    new Request('https://c8f7dbf7.auto-research-private.pages.dev/progress/example/?view=full'),
+    assets(),
+  );
+  assert.equal(response.status, 307);
+  assert.equal(response.headers.get('location'), `https://${canonical}/progress/example/?view=full`);
+});