Q: session_start() messes up PDF download through PHP in IE8 I use this code to send an PDF through PHP to the visitor ([link][1]):
session_start();

$fileName = '0-1.pdf';
$file = '../invoices/'. $fileName;
if (file_exists($file)) {
  $size = filesize($file);  
  header('Content-Disposition: attachment; filename="'. $fileName .'"');
  header('Content-Length: '.$size);  
  header('Content-type: application/octetstream');
  #header('Content-type: application/pdf');
  echo file_get_contents($file);
}

It works well on Chrome, FF and IE 9 but fails on IE 8.
The reason it fails is
session_start();

If I leave it out, it will work in IE 8 as well.
Unfortunately I need the session. Since the whole reason for passing the PDF through PHP is to perform an authentication check. So I need the session ID to check if the current user is allowed to access the PDF.
Any ideas how to get the download to work in IE 8 with the headers session_start() sends?

A: Just found the solution.
Aftter session_start() I have to set theese headers to get it to work with IE 8:
header("Cache-Control: must-revalidate, post-check=0, pre-check=0"); 
header("Pragma: public");

Strange behaviour... But it works now :-)
