feat: add sitemap (#9)

src/pages/sitemap.xml.ts

@@ -0,0 +1,23 @@
+import type { APIContext } from 'astro'
+import { getCollection } from 'astro:content'
+
+
+export async function GET(context: APIContext) {
+  const notes = await getCollection('notes')
+
+  let sitemap = `<?xml version="1.0" encoding="UTF-8"?>
+    <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" xmlns:xhtml="http://www.w3.org/1999/xhtml">
+      <url><loc>${context.site}</loc></url>
+      <url><loc>${context.site}services</loc></url>
+      <url><loc>${context.site}cinema</loc></url>`
+
+  notes.forEach(note => {
+    sitemap += `<url><loc>${context.site}notes/${note.slug}</loc></url>`
+  })
+
+  sitemap += '</urlset>'
+
+  const resp = new Response(sitemap)
+  resp.headers.set("Content-Type", "application/xml")
+  return resp
+}