Sure. Here's the help system one (no longer used since intercom now supports permissions, and I opened up the help system anyway):

    addEventListener('fetch', event => {
       event.respondWith(handleRequest(event.request))
     })

    async function handleRequest(request) {
       const cookie = request.headers.get('Cookie');
       if (cookie && cookie.includes('foo=bar')) {
         return await fetch(request);
       } else {
         return new Response('You must log in before accessing this content');
       }
     }

The encrypted URL script is actually a bit longer than "5 lines" (it has been a while) so here's a gist:

https://gist.github.com/stickfigure/af592b1ce7f888c5b8a4efbe...