async function handleRequest(req) {
  // Set up the regular expression
  const hostRegex = new RegExp("^(.+?\.){2}fiddle\.", "g");
  // Check if the host matches the regular expression
  const hostMatch = hostRegex.exec(req.headers.get("Host").toLowerCase());

  // Check if the host has a subdomain
  if (hostMatch) {
    // This host has a subdomain
    // Parse the URL from client request
    let url = new URL(req.url);
    // Alter the URL to a sub-folder
    url.pathname = "/subcontent/" + url.pathname;
    req = new Request(url, req);
  }

  const backendResponse = fetch(req, {
    backend: "origin_0"
  });

  return backendResponse;
}

addEventListener("fetch", (event) => event.respondWith(handleRequest(event.request)))