feat: allow staff to revalidate the homepage

src/lib/session-utils.ts

@@ -0,0 +1,26 @@
+import type { Session } from "next-auth";
+
+type ValidationFailure = {
+  err: Error;
+  data: null;
+};
+
+type ValidationSuccess<T> = {
+  err: null;
+  data: T;
+};
+
+type Validated<T> = ValidationFailure | ValidationSuccess<T>;
+
+export const isStaff = (email?: string): boolean =>
+  !!email && email.endsWith("@freecodecamp.org");
+
+export const getEmailFromSession = (
+  session: Session | null
+): Validated<{ email: string }> => {
+  if (!session) return { err: Error("No session"), data: null };
+  if (!session.user) return { err: Error("No user"), data: null };
+  if (!session.user.email) return { err: Error("No email"), data: null };
+
+  return { err: null, data: { email: session.user.email } };
+};

src/pages/api/revalidate.ts

@@ -0,0 +1,24 @@
+import { getServerSession } from "next-auth/next";
+
+import { getEmailFromSession, isStaff } from "@/lib/session-utils";
+import { authOptions } from "@/pages/api/auth/[...nextauth]";
+import type { NextApiRequest, NextApiResponse } from "next";
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  const session = await getServerSession(req, res, authOptions);
+  const { email } = getEmailFromSession(session).data ?? {};
+
+  if (isStaff(email)) {
+    try {
+      await res.revalidate("/");
+      return res.json({ revalidated: true });
+    } catch (err) {
+      return res.status(500).json({ message: "Could not revalidate" });
+    }
+  } else {
+    res.status(403).end();
+  }
+}