fix: read a member's descriptor from the page's own rel=openwebring link

apps/web/test/openwebring.test.js

@@ -254,6 +254,30 @@ test('a descriptor naming the ring counts as linking back', () => {
   assert.equal(descriptorUrlFor('not a url'), null);
 });
 
+test('a member on a shared host points at its descriptor from the page, and the check follows it', async () => {
+  // A blog under /~name/ cannot put a file at the host's /.well-known/, so its
+  // page says where the file is (the spec's second discovery route). The
+  // href is relative and the rel is one of several.
+  const site = 'https://host.example/~name/blog/';
+  const page = `<link rel="alternate openwebring" href="openwebring.json"><a href="${BASE}/ring/physics/next?from=${site}">next</a>`;
+  const asked = [];
+  const fetchText = async (url, opts) => {
+    asked.push(url);
+    if (url === site) return page;
+    if (url === 'https://host.example/~name/blog/openwebring.json') return JSON.stringify({ made_by: 'both', disclosure: 'ai-assisted', rings: [] });
+    return null;
+  };
+  const found = await checkRingMember({ base: BASE, ringSlug: 'physics', memberUrl: site, fetchText });
+  assert.deepEqual(found, { status: 'active', linked: 'page', reachable: true, madeBy: 'both', disclosure: 'ai-assisted', descriptorUrl: 'https://host.example/~name/blog/openwebring.json' });
+  assert.deepEqual(asked, [site, 'https://host.example/.well-known/openwebring.json', 'https://host.example/~name/blog/openwebring.json'], 'the origin first, then the page\'s own pointer');
+
+  // No pointer and no well-known file: nothing is fetched a third time.
+  const bare = [];
+  const none = await checkRingMember({ base: BASE, ringSlug: 'physics', memberUrl: site, fetchText: async (url) => { bare.push(url); return url === site ? '<p>plain</p>' : null; } });
+  assert.equal(none.madeBy, null);
+  assert.equal(bare.length, 2);
+});
+
 test('checking a member asks two URLs and decides from both', async () => {
   const page = `<a href="${BASE}/ring/physics/next?from=https://alpha.example/">next</a>`;
   const descriptor = JSON.stringify({ made_by: 'both', disclosure: 'ai-assisted', rings: [] });

packages/ingest/src/webring.js

@@ -80,6 +80,35 @@ export function linksToRing(html, base, slug) {
  * @param {string} siteUrl
  * @returns {string|null}
  */
+/**
+ * The descriptor a page points at with <link rel="openwebring" href="...">,
+ * resolved against the page, or null. The spec's second discovery route:
+ * a member whose site is a path on a shared host (a user directory, a blog
+ * under /~name/) cannot put a file at that host's /.well-known/, so the
+ * page says where the file is instead. Attribute order is not assumed.
+ *
+ * @param {string|null|undefined} html
+ * @param {string} pageUrl
+ * @returns {string|null}
+ */
+export function descriptorLinkFrom(html, pageUrl) {
+  if (typeof html !== 'string') return null;
+  const tags = html.match(/<link\b[^>]*>/gi) ?? [];
+  for (const tag of tags) {
+    const rel = /\brel\s*=\s*["']([^"']*)["']/i.exec(tag)?.[1]?.toLowerCase() ?? '';
+    if (!/\bopenwebring\b/.test(rel)) continue;
+    const href = /\bhref\s*=\s*["']([^"']*)["']/i.exec(tag)?.[1]?.trim();
+    if (!href) continue;
+    try {
+      const u = new URL(href, pageUrl);
+      if (/^https?:$/.test(u.protocol)) return u.toString();
+    } catch {
+      // A href that is not a URL is no descriptor.
+    }
+  }
+  return null;
+}
+
 export function descriptorUrlFor(siteUrl) {
   try {
     const u = new URL(siteUrl);
@@ -223,12 +252,23 @@ export async function checkRingMember({ base, ringSlug, memberUrl, fetchText })
   const html = await fetchText(memberUrl, { accept: 'text/html' }).catch(() => null);
   const linkedFromPage = linksToRing(html, base, ringSlug);
 
-  const descriptorUrl = descriptorUrlFor(memberUrl);
+  // The well-known file on the origin first; when there is none, the file
+  // the page itself points at. Both are the member's own words; a page on a
+  // shared host has only the second.
+  let descriptorUrl = descriptorUrlFor(memberUrl);
   let descriptor = null;
   if (descriptorUrl) {
     const text = await fetchText(descriptorUrl, { accept: 'application/json' }).catch(() => null);
     descriptor = parseRingDescriptor(text);
   }
+  if (!descriptor) {
+    const linked = descriptorLinkFrom(html, memberUrl);
+    if (linked && linked !== descriptorUrl) {
+      const text = await fetchText(linked, { accept: 'application/json' }).catch(() => null);
+      descriptor = parseRingDescriptor(text);
+      if (descriptor) descriptorUrl = linked;
+    }
+  }
   const namedInDescriptor = descriptorNamesRing(descriptor, base, ringSlug);
 
   return {