Fix for some variables($_SERVER['HTTPS'], $_SERVER['SERVER_PORT'], $_SERVER['REQUEST_URI']) for Wordpress based site, which prevents 'Too many redirects' error. · Issue #545 · nginx/unit · GitHub
Global Variables - Superglobals Several predefined variables in PHP are "superglobals", which means that they are always accessible, regardless of scope. - ppt download
PHP header - Phppot
PHP: get relevant URL of the current page using $_SERVER array - YouTube