从URL而不是http_referer获取重定向

Question

I am redirecting request from server A to B.

On server B I can get referer from http_referer variable as it is from A when someone clicks on the link.

What if someone redirecting from A -> B via .htaccess or similar like this, http_referer is empty.

I need to identify from which server request coming.

I am doing the CURL request internally but this is a very heavy process.

Any suggestions?

RedirectPermanent A.com/test 'http://B.com/shop/?ref=123'