Formating results of a directory using jstree

Question 1

I found what I was doing wrong, the sctructure of array (that I was building JSON) was wrong. I was doing this:

$listDir = array(
   'data' => basename($dir),
   'attr' => array (
      'rel' => 'folder'
    ),
    'metadata' => array (
       'id' => $dir
    ),
    'children' => array()
);

But the correct structure (in version 3.0 of jstree) is:

$listDir = array(
   'id' => basename($dir),
   'text' => basename($dir),
   'children' => array()
);

So, my php file (dir2json.php) looks like this:

header("Content-Type: application/json");
echo json_encode(dir_to_jstree_array("/var/www/html/images"));

function dir_to_jstree_array($dir, $order = "a", $ext = array()) {      
  if(empty($ext)) {
     $ext = array (
        "jpg", "gif", "jpeg", "png", "doc", "xls", "pdf", "tif", "ico", "xcf", "gif87", "scr"
     );
  }

  $listDir = array(
            'id' => basename($dir),
            'text' => basename($dir),
        'children' => array()
  );

  $files = array();
  $dirs = array();

  if($handler = opendir($dir)) {
     while (($sub = readdir($handler)) !== FALSE) {
        if ($sub != "." && $sub != "..") {
           if(is_file($dir."/".$sub)) {
              $extension = pathinfo($dir."/".$sub, PATHINFO_EXTENSION);
              if(in_array($extension, $ext)) {
                 $files []= $sub;
              }
           } 
           elseif (is_dir($dir."/".$sub)) {
              $dirs []= $dir."/".$sub;
           }
        }
     }
     if($order === "a") {
       asort($dirs);
     } 
     else {
        arsort($dirs);
     }

     foreach($dirs as $d) {
        $listDir['children'][]= dir_to_jstree_array($d);
     }

     if($order === "a") {
        asort($files);
     } 
     else {
        arsort($files);
     }

     foreach($files as $file) {
        $listDir['children'][]= $file;
     }

     closedir($handler);
  }
  return $listDir;
}

Question 2

for add icon to your file you can use this code :

last code :

foreach($files as $file) {
    $listDir['children'][]= $file;
 }

new code :

foreach($files as $file) {
            $exten = pathinfo($file, PATHINFO_EXTENSION);
            if(in_array($exten, $ext)) {
                $icon = '';
                if($exten == 'jpg' or $exten == 'png' or $exten == 'jpeg' or $exten == 'gif' or $exten == 'ico'){
                    $icon = 'fa fa fa-file-image-o';
                }// end if
                if($exten == 'doc' or $exten == 'docx'){
                    $icon = 'fa fa-file-word-o';
                }
                if ($exten == 'txt'){
                    $icon = 'fa fa-file-text-o';
                }
                if ($exten == 'pdf'){
                    $icon = 'fa fa-file-pdf-o';
                }
                if ($exten == 'xls'){
                    $icon = 'fa fa-file-excel-o';
                }
                if ($exten == 'zip'){
                    $icon = 'fa fa-file-archive-o';
                }
            }
            $listDir['children'][]= array('id' => $dir.'/'.$file , 'text' => $file , 'icon' => $icon);
        }