def handle_headers(frame, request, response): resource_url = request.GET.first(b"resource-url").decode() link_header_value = "<{}>; rel=preload; as=script".format(resource_url) early_hints = [ (b":status", b"103"), (b"link", link_header_value), ] response.writer.write_raw_header_frame(headers=early_hints, end_headers=True) response.status = 200 response.headers[b"content-type"] = "text/html" if b"x-frame-options" in request.GET: x_frame_options = request.GET.first(b"x-frame-options").decode() response.headers[b"x-frame-options"] = x_frame_options response.write_status_headers() def main(request, response): content = "" response.writer.write_data(item=content, last=True)