if ($request_method = 'OPTIONS') {
    more_set_headers 'Access-Control-Allow-Origin: $http_origin';
    more_set_headers 'Access-Control-Allow-Credentials: true';
    more_set_headers 'Access-Control-Allow-Methods: GET, POST, OPTIONS, PUT, DELETE';
    more_set_headers 'Access-Control-Allow-Headers: DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
    more_set_headers 'Access-Control-Max-Age: 1728000';
    more_set_headers 'Content-Type: text/plain; charset=utf-8';
    more_set_headers 'Content-Length: 0';
    return 204;
}

more_set_headers 'Access-Control-Allow-Origin: $http_origin';
more_set_headers 'Access-Control-Allow-Credentials: true';
more_set_headers 'Access-Control-Allow-Methods: GET, POST, OPTIONS, PUT, DELETE';
more_set_headers 'Access-Control-Allow-Headers: DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
more_set_headers 'Access-Control-Expose-Headers: Content-Length,Content-Range,Skynet-File-Metadata,Skynet-Skylink,Skynet-Portal-Api';