Amazon s3 sdk return folders only via prefix

Amazon s3 sdk return folders only via prefix
function getPlaylist($id){
	   
	   $bucket = 'bucket-name';
	   $s3 = $this->awslib->loader();
	   $response = $s3->list_objects($bucket, array(
	          'delimiter' => '/',
	          'prefix' => $id . '/'
			));
		
		//print_r($response);
	   $playlist = array();	
	   foreach ($response->body as $object) {
		   if($object->Prefix){
		   $playlist[]  = array('folder' => $this->xmldecode($object->Prefix));
		   }
	   }

       return $playlist;
	
	}	
	
	function xmldecode($txt){
		$txt = str_replace('&',		'&',	$txt);
		$txt = str_replace('&lt;',		'<',	$txt);
		$txt = str_replace('&gt;',		'>',	$txt);
		$txt = str_replace('&apos;',	"'",	$txt);
		$txt = str_replace('&quot;', 	'"',	$txt);
		return $txt;
	}