Hot-link protection

const handler: ExportedHandler = {
  async fetch(request) {
    const HOMEPAGE_URL = "https://tutorial.cloudflareworkers.com/";
    const PROTECTED_TYPE = "image/";

    // 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;
  },
};

export default handler;