Change headers

async function handleRequest(request: Request) {
  const proxyHeader = request.headers.get("x-swarmd-proxy");

  if (proxyHeader == null) {
    return new Response("Nothing to see here", { status: 404 })
  } else {
    // We check that it's a proper URL.
    if (URL.canParse(proxyHeader)) {
      const url = new URL(proxyHeader);
      const now = performance.now();
      const response = await fetch(url);
      const elapsed = performance.now() - now;

      // Headers are immutable on the fetch response
      const newResponse = new Response(response.body, response);

      // Time to fetch the expected ressource
      newResponse.headers.append("x-swarmd-response", `${elapsed}ms`);
      return newResponse;
    }
    return new Response("Not an URL", { status: 500 });
  }
}

async function onRequest({ req }) {
  const request = req.request;

  if (request.method !== "GET") return new Response("Not Allowed", {
    status: 405,
    header: {
      Allow: "GET"
    }
  });

  req.respondWith(await handleRequest(request))
}

export { onRequest }