PHP Web Output File

<?php

 function FunctionName($file)
 {
  if (file_exists($file)) {
   header('Content-Description: File Transfer');
   header('Content-Type: application/octet-stream');
   header('Content-Disposition: attachment; filename="' . basename($file) . '"');
   header('Expires: 0');
   header('Cache-Control: must-revalidate');
   header('Pragma: public');
   header('Content-Length: ' . filesize($file));
   readfile($file);
   exit;
  }
 }
?>