public function sendFile($file, $name=NULL, $contentType='application/octet-stream', $contentDisposition='attachment'){
        if($name == NULL){
            $name= basename($file);
        }
        header('Content-Description: File Transfer');
        header('Content-Type: '.$contentType);
        header('Content-Disposition: '.$contentDisposition.'; filename="'.$name.'"');
        header('Pragma: public');
        header('Content-Length: ' . filesize($file));
        readfile($file);        
    }