Hot-link protection

const HOMEPAGE_URL = 'https://tutorial.cloudflareworkers.com/';
const PROTECTED_TYPE = 'image/';

async function handleRequest(request) {
  // Fetch the original request
  const response = await fetch(request);

  // If it's an image, engage hotlink protection based on the
  // Referer header.
  const referer = request.headers.get('Referer');
  const contentType = response.headers.get('Content-Type') || '';

  if (referer && contentType.startsWith(PROTECTED_TYPE)) {
    // If the hostnames don't match, it's a hotlink
    if (new URL(referer).hostname !== new URL(request.url).hostname) {
      // Redirect the user to your website
      return Response.redirect(HOMEPAGE_URL, 302);
    }
  }

  // Everything is fine, return the response normally.
  return response;
}

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