I am trying to implement the checkscript feature of uploadify in an asp.net mvc view but i can't determine what the key is i should be using on the controller side. Below is the php script but i am not very familiar with php and can't determine what php is scraping out of the httprequest. Has anyone implemented this? The documentation is a little sparse (as in nonexistent).

$fileArray = array();
foreach ($_POST as $key => $value) {
    if ($key != 'folder') {
    	if (file_exists($_SERVER['DOCUMENT_ROOT'] . $_POST['folder'] . '/' . $value)) {
    		$fileArray[$key] = $value;
    	}
    }
}
echo json_encode($fileArray);
?>