CTAO Science Portal: static Astro site with git-based CMS (Sveltia + Gitea)

Portal code only; editorial content lives in the ctao/content repo on the
demo machine's Gitea and is overlaid at build time (see README.md and
deploy/README.md). Live demo: https://astro.isl-dev.grid.cyfronet.pl

src/pages/rss.xml.js

@@ -0,0 +1,43 @@
+// RSS 2.0 feed — hand-rolled static endpoint like search.json.js (no @astrojs/rss
+// dependency; the spec is 20 lines of XML). Newest 30 items, absolute URLs from
+// the configured `site`.
+import { getCollection } from 'astro:content';
+
+const esc = (s = '') =>
+  s.replace(/[<>&'"]/g, (c) => ({ '<': '&lt;', '>': '&gt;', '&': '&amp;', "'": '&apos;', '"': '&quot;' })[c]);
+
+export async function GET(context) {
+  const site = context.site; // always set in astro.config.mjs
+  const posts = (await getCollection('news', ({ data }) => !data.draft))
+    .sort((a, b) => b.data.date.valueOf() - a.data.date.valueOf())
+    .slice(0, 30);
+
+  const items = posts
+    .map((p) => {
+      const url = new URL(`/news/${p.id}`, site).href;
+      return `    <item>
+      <title>${esc(p.data.title)}</title>
+      <link>${url}</link>
+      <guid isPermaLink="true">${url}</guid>
+      <pubDate>${p.data.date.toUTCString()}</pubDate>
+      <description>${esc(p.data.description)}</description>
+      <category>${esc(p.data.category)}</category>
+    </item>`;
+    })
+    .join('\n');
+
+  const xml = `<?xml version="1.0" encoding="UTF-8"?>
+<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
+  <channel>
+    <title>CTAO Science Portal News</title>
+    <link>${new URL('/news', site).href}</link>
+    <description>News and announcements of the Cherenkov Telescope Array Observatory</description>
+    <language>en</language>
+    <lastBuildDate>${(posts[0]?.data.date ?? new Date()).toUTCString()}</lastBuildDate>
+    <atom:link href="${new URL('/rss.xml', site).href}" rel="self" type="application/rss+xml"/>
+${items}
+  </channel>
+</rss>
+`;
+  return new Response(xml, { headers: { 'Content-Type': 'application/rss+xml; charset=utf-8' } });
+}