PHP readfile() causing corrupt file downloads

Question

I am using php script to provide download from my website after a requisite javascript timer this php script is included which causes the download. But the downloaded file i

Answer 1

           ob_start();//add this to the beginning of your code 

      if (file_exists($filepath) && is_readable($filepath) ) {
header('Content-Description: File Transfer');
 header("Content-Type: application/octet-stream");
 header("Content-Disposition: attachment; filename=$files");
 header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
   header('Pragma: public');
 header("content-length=".filesize($filepath));
 header("Content-Transfer-Encoding: binary");

   /*add while (ob_get_level()) {
       ob_end_clean();
         }  before readfile()*/
  while (ob_get_level()) {
ob_end_clean();
   }
    flush();
   readfile($filepath);