php如何向上移动目录直到特定文件

Question

lets say i have a directory structure like this

____
|  Root
    |_____
       Folder1
    |_____
       Folder2
         |_____
            Subfolder2.1
            Subfolder2.2
                 |______
                    Subfolder2.2.1

if i wanted to move upwards from Subfolder2.1 to the Root folder i would have to do ../../ and if i have to move from Subfolder2.2.1 to Root i would have to do ../../../ is there a way in php or in regular expression to write an expression that goes back up the directory until it finds a specific file name (root)

currently in symfony framework i'm doing something like $defaultTemplate = '::../../../../../app/Resources/views/'.$input->getOption('mytwigdest') to create a template inside a directroy

ofcourse this only works for one level of folders not its subfolders or its parent folder, what expression do i need to put in instead of the ../ so that it goes up the directories until it finds a specific directory name

__ DIR __ and symfony's $this->container->getParameter('kernel.root_dir') would not work as it would give me the current file's path which is entirely different from where i'm creating a template using $defaultTemplate

Answer 1

Although I'm not sure why you need to go with such a way to solve your problem, this will calculate number of parent directories ../ to a custom directory. You only want to change the name. Here it is Root :

str_repeat("../", count(explode(DIRECTORY_SEPARATOR , __FILE__)) - (1 + array_flip(explode(DIRECTORY_SEPARATOR , __FILE__))['Root']));

Put all things together:

$defaultTemplate = '::'.str_repeat("../", count(explode(DIRECTORY_SEPARATOR , __FILE__)) - (1 + array_flip(explode(DIRECTORY_SEPARATOR , __FILE__))['Root'])).'app/Resources/views/'.$input->getOption('mytwigdest');

Answer 2

 include($_SERVER['DOCUMENT_ROOT'].'/index.php');

Will always find the direct to root folder. Note you need / after $_SERVER.