我怎样才能制作一个Nodejs express呢?js(代理)服务器只能用于特定的域吗?

I have developed a small images proxy in node.js (expressjs). This proxy should reduce all images, which come from my website "www.myUrl.com". This also works well so far. But I would like to protect the proxy against unauthorized access. That is, as soon as an image is loaded via the proxy from another url, an error message "unauthorized" or null ... is to be returned. I have already tried to read the header "origin" via I have developed a small images proxy in node.j