publish sitemap.xml with getServerSideProps instead of next-sitemap (#720)

very VERY hacky right now but I still prefer this

pages/sitemap.xml.ts

@@ -0,0 +1,70 @@
+// WARNING: THIS FILE CONTAINS HISTORICAL LEVELS OF HACKINESS AND SHOULD NOT BE REPLICATED NOR ADMIRED.
+
+import { getAllNotes } from "../lib/parse-notes";
+import { baseUrl } from "../lib/config";
+import type { GetServerSideProps } from "next";
+
+const Sitemap = () => null;
+
+type Page = {
+  relUrl: string;
+  priority?: number;
+  changeFreq?: string;
+  lastMod?: string | Date;
+};
+
+export const getServerSideProps: GetServerSideProps = async (context) => {
+  // TODO: make this not manual (serverless functions can't see /pages at runtime)
+  const pages: Page[] = [
+    { relUrl: "/", priority: 1.0, changeFreq: "weekly" }, // homepage
+    { relUrl: "/notes/" },
+    { relUrl: "/birthday/" },
+    { relUrl: "/cli/" },
+    { relUrl: "/contact/" },
+    { relUrl: "/hillary/" },
+    { relUrl: "/leo/" },
+    { relUrl: "/license/", priority: 0.1, changeFreq: "yearly" },
+    { relUrl: "/previously/" },
+    { relUrl: "/privacy/", priority: 0.1, changeFreq: "yearly" },
+    { relUrl: "/projects/", changeFreq: "daily" },
+    { relUrl: "/uses/" },
+  ];
+
+  // push notes separately and use their metadata
+  getAllNotes().map((note) =>
+    pages.push({
+      relUrl: `/notes/${note.slug}/`,
+      // pull lastMod from front matter date
+      lastMod: note.date,
+    })
+  );
+
+  const xml = `<?xml version="1.0" encoding="UTF-8"?>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+  ${pages
+    .map(
+      (page) => `
+  <url>
+    <loc>${baseUrl}${page.relUrl}</loc>
+    <priority>${page.priority ? page.priority.toFixed(1) : 0.7}</priority>
+    <changefreq>${page.changeFreq || "monthly"}</changefreq>
+    <lastmod>${page.lastMod || new Date().toISOString()}</lastmod>
+  </url>`
+    )
+    .join("")
+    .trim()}
+</urlset>`;
+
+  const { res } = context;
+  res.setHeader("content-type", "application/xml; charset=utf-8");
+  // cache on edge for one hour
+  res.setHeader("cache-control", "s-maxage=3600, stale-while-revalidate");
+  res.write(xml);
+  res.end();
+
+  return {
+    props: {},
+  };
+};
+
+export default Sitemap;