Arlo

Hi all. I have a website where most of my webpages automatically redirect the viewer to a PHP file on my site, and that PHP file needs to know which page redirected them there. But the problem is, $_SERVER['HTTP_REFERER'] and $_SERVER['REDIRECT_URL'] are only set when the user clicks a link to go to a different page, not when they're redirected. But surely there must be some way for pages to know which webpage redirected them there, no? Does anyone know how to do this?