proxy_cache not honoring pragma/cache-control settings

[pk899]

Hi, from the documentation I understand that proxy_cache will NOT be
activated for pages that have pragma to "no-cache" or Cache-control to
"no-cache", or even Expires to an old date. 

I have the following in my Location settings: 

   proxy_cache_bypass          $http_pragma  $http_authorization;
   proxy_no_cache              $http_pragma  $http_authorization;


And this at the top of my PHP pages that I do not want cached, as they
change often and for the logged in user: 


   header("Cache-control: private, no-cache, must-revalidate");
   header("Expires: Mon, 24 Sep 1997 05:00:00 GMT"); # Past date
   header("Pragma: no-cache");


However, these pages are still being cached. 

Any insight on what I am missing? 

Thanks!

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,204026,204026#msg-204026