在没有硬编码的情况下获取dev和prod的网站root

My dev server is http://localhost/mygreatapp and my production server is http://www.myawesomesite.com but maybe someday it will migrate to http://www.myawesomesite.com/mygreatapp

In these cases mygreatapp is a virtual directory.

I would like a php function to return the correct website roots without having to hard-code anything (e.g., mygreatapp), regardless if it's off the default website or a virtual directory. In either case, that's where all the relative paths to the files begins.

I have looked at the similar questions and not found a solution that does not involve hard-coding, which would then involve having to update the value for each environment, painful and error prone.

This will get my by for now, but I'll need to adjust it if I go into a subfolder on a linux machine.

public static function WebRoot(){
        $virtualdir = '';
        if(isset($_SERVER['APPL_MD_PATH'])){
            $virtualdir = substr($_SERVER['APPL_MD_PATH'], strpos($_SERVER['APPL_MD_PATH'], '/ROOT/') + strlen('/ROOT/'));
        }
        return 'https://'.$_SERVER['SERVER_NAME'].'/'.$virtualdir.'/';
}