Validate favicon hosts against the Public Suffix List (tldts)

Replace the ad-hoc .local/private-IP regex with a PSL check via tldts:
only emit a favicon for a registrable domain under an ICANN suffix. This
correctly excludes .local/.internal hosts, single-label names, IPs, and
invalid TLDs, while handling multi-part suffixes (gov.in, gov.uk, …). The
homepage client now trusts the server-computed api.json icon instead of
re-deriving the URL.

Author: RhysSullivan

output/cli.json

@@ -411,7 +411,7 @@
     "name": "gcloud",
     "description": "Manage Google Cloud resources, IAM, and deployments.",
     "url": "https://cloud.google.com/sdk/gcloud",
-    "icon": "https://cloud.google.com/favicon.ico",
+    "icon": "https://google.com/favicon.ico",
     "categories": [],
     "feeds": [
       "cli-seed"

output/index.json

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:7d0b60f9d8ddc2fe01f481554f540d2d37e3886d48f0c3c782d1a02cb0192dfa
-size 58957466
+oid sha256:53aaa337540f3bad7f4763585d648ddaa22b6579668f7b51821453f3f2080f50
+size 58957376

output/openapi.json

@@ -1,14 +1,17 @@
-// Private/non-routable host ranges. We must NOT emit favicon URLs for these:
-// a public page requesting a LAN address (`.local`, localhost, private IP)
-// triggers the browser's Local Network Access permission prompt.
-const PRIVATE_IP = /^(10|127)\.\d|^192\.168\.|^172\.(1[6-9]|2\d|3[01])\./;
+import { parse } from "tldts";
 
-/** Favicon URL for a domain, or null when the host isn't publicly routable. */
+/**
+ * Favicon URL for a domain, or null when it isn't a real public registrable
+ * domain. Validated against the Public Suffix List (via tldts): we require a
+ * registrable domain under an ICANN suffix. This excludes `.local`/`.internal`
+ * hosts, single-label names, IP addresses, and invalid TLDs — requesting a
+ * favicon from any of those is wrong, and LAN hosts trigger the browser's
+ * Local Network Access permission prompt. Multi-part suffixes (gov.in, gov.uk,
+ * com.au, …) resolve correctly because the PSL knows them.
+ */
 export function faviconUrl(domain: string | null | undefined): string | null {
   if (!domain) return null;
-  const d = domain.toLowerCase();
-  if (!d.includes(".")) return null; // single-label host (not a public FQDN)
-  if (d === "localhost" || d.endsWith(".local") || d.endsWith(".internal") || d.endsWith(".localhost")) return null;
-  if (PRIVATE_IP.test(d)) return null;
-  return `https://${domain}/favicon.ico`;
+  const info = parse(domain);
+  if (info.isIp || !info.domain || !info.isIcann) return null;
+  return `https://${info.domain}/favicon.ico`;
 }

public/api.json

@@ -72,14 +72,6 @@ const counts = {
 
   const esc = (s) =>
     String(s).replace(/[&<>"']/g, (c) => ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#39;" }[c]));
-  // Favicon URL, or "" for non-public hosts (.local / localhost / private IP)
-  // — requesting those from a public page triggers a Local Network Access prompt.
-  const fav = (d) => {
-    const h = String(d).toLowerCase();
-    if (!h.includes(".") || h === "localhost" || h.endsWith(".local") || h.endsWith(".internal") ||
-        h.endsWith(".localhost") || /^(10|127)\.\d|^192\.168\.|^172\.(1[6-9]|2\d|3[01])\./.test(h)) return "";
-    return `https://${d}/favicon.ico`;
-  };
   const dpath = (d) => `/d/${encodeURIComponent(d)}/`;
 
   const buildGroups = (recs) => {
@@ -100,9 +92,9 @@ const counts = {
 
   const groupRowHtml = (g) => {
     const ph = esc((g.domain[0] || "?").toUpperCase());
-    const src = g.icon || fav(g.domain);
-    const icon = src
-      ? `<img class="c-fav" src="${esc(src)}" alt="" loading="lazy" width="18" height="18" onerror="this.outerHTML='<span class=&quot;ph&quot;>${ph}</span>'">`
+    // g.icon is the PSL-validated favicon URL from api.json (null for non-public hosts).
+    const icon = g.icon
+      ? `<img class="c-fav" src="${esc(g.icon)}" alt="" loading="lazy" width="18" height="18" onerror="this.outerHTML='<span class=&quot;ph&quot;>${ph}</span>'">`
       : `<span class="ph">${ph}</span>`;
     const chips = TORDER.filter((t) => g.types[t]).map((t) => {
       const c = g.types[t];