(PHP 5 >= 5.4.0, PHP 7, PHP 8)
The callback should accept up to three arguments: the current item, the current key and the iterator, respectively.
Example #1 Available callback arguments
<?php
/**
* Callback for RecursiveCallbackFilterIterator
*
* @param $current Current item's value
* @param $key Current item's key
* @param $iterator Iterator being filtered
* @return boolean TRUE to accept the current item, FALSE otherwise
*/
function my_callback($current, $key, $iterator) {
// Your filtering code here
}
?>
Filtering a recursive iterator generally involves two conditions.
The first is that, to allow recursion, the callback function should return true
if the current iterator item has children.
The second is the normal filter condition, such as a file size or extension
check as in the example below.
Example #2 Recursive callback basic example
<?php
$dir = new RecursiveDirectoryIterator(__DIR__);
// Filter large files ( > 100MB)
$files = new RecursiveCallbackFilterIterator($dir, function ($current, $key, $iterator) {
// Allow recursion
if ($iterator->hasChildren()) {
return TRUE;
}
// Check for large file
if ($current->isFile() && $current->getSize() > 104857600) {
return TRUE;
}
return FALSE;
});
foreach (new RecursiveIteratorIterator($files) as $file) {
echo $file->getPathname() . PHP_EOL;
}
?>