Create an array of folders in a directory, recursively.

get_folders_recursive.php

<?php 
function add_folders($root) {
    $local_folders_array = array();
    foreach (glob("$root/*", GLOB_ONLYDIR) as $folder) {
        array_push($local_folders_array, ['foldername' => $folder]);
        $arr2 = add_folders($folder);
        if (count($arr2) > 0) foreach($arr2 as $subfolder) array_push($local_folders_array, ['foldername' => $subfolder['foldername']]);
    }
    return $local_folders_array;
}