initialize project with basic structure and dependencies

server/api/courses/index.post.ts

@@ -1,8 +1,13 @@
 import { db } from "../../db/index";
 import { courses } from "../../db/schema";
 import { randomUUID } from "crypto";
+import { verifyLicenseKey } from "../../utils/license";
 
-export default defineEventHandler(async () => {
+export default defineEventHandler(async (event) => {
+  const key = getHeader(event, "x-license-key") ?? "";
+  if (!verifyLicenseKey(key)) {
+    throw createError({ statusCode: 401, message: "Invalid or expired license key" });
+  }
   const id = randomUUID();
 
   await db.insert(courses).values({

server/utils/license.ts

@@ -0,0 +1,31 @@
+import { createPublicKey, verify } from "crypto";
+
+function getPublicKey() {
+  const b64 = process.env.LICENSE_PUBLIC_KEY;
+  if (!b64) throw createError({ statusCode: 500, message: "License system not configured" });
+
+  return createPublicKey({
+    key: Buffer.from(b64, "base64"),
+    format: "der",
+    type: "spki",
+  });
+}
+
+export function verifyLicenseKey(key: string): boolean {
+  try {
+    const pubKey = getPublicKey();
+    const now = Math.floor(Date.now() / 1000 / 300);
+
+    const sig = Buffer.from(key, "base64url");
+
+    // accept current window and the one before (edge case tolerance)
+    for (const window of [now, now - 1]) {
+      const msg = Buffer.from(String(window));
+      if (verify(null, msg, pubKey, sig)) return true;
+    }
+
+    return false;
+  } catch {
+    return false;
+  }
+}