Redirect response

async function handleRequest(request) {
  const url = new URL(request.url)
  let image_url = url.searchParams.get("sub_url")

  if (!image_url) return new Response("Error. No sub_url URL param detected", { status: 500 })

  // Rewrite request to point to API url. This also makes the request mutable
  // so we can add the correct Origin header to make the API server think
  // that this request isn't cross-site.
  request = new Request(sub_url, request);
  request.headers.set("Origin", new URL(sub_url).origin);
  request.headers.set("user-agent", "1337 User Agent");
  request.headers.set("Referer", new URL(sub_url).origin);

  let response = await fetch(request)

  // Recreate the response so we can modify the headers
  response = new Response(response.body, response)

  // Set CORS headers
  response.headers.set("Cross-Origin-Resource-Policy", "cross-origin")

  // Append to/Add Vary header so browser will cache response correctly
  response.headers.append("Vary", "Origin")
  return response
}

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

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

  const response = await handleRequest(request);
  req.respondWith(response);
}

export { onRequest }