From:             pornel at despammed dot com
Operating system: *
PHP version:      Irrelevant
PHP Bug Type:     Documentation problem
Bug description:  Some of suggested no-cache headers are useless

Description:
------------
In http://php.net/header

// Date in the past
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
// always modified
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
// HTTP/1.1
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
// HTTP/1.0
header("Pragma: no-cache");


Despite disclaimer under this example I think useless headers should be
removed.

last-modified is last resort in finding freshness of an object, and is not
needed when expires and cache-control are present.

post-check and pre-check headers are always ignored when no-cache is
specified. 

on most proxies no-cache and no-store make no difference, but the latter
may impose extra restrictions in handling "sensitive information" and
should not be abused just for any dynamic data.



Expected result:
----------------
header("Cache-Control: no-cache, must-revalidate");
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");

Actual result:
--------------
abuse of http by clueless copy'n'pasters.
backtraces to these lines in php docs :)


-- 
Edit bug report at http://bugs.php.net/?id=34223&edit=1
-- 
Try a CVS snapshot (php4):   http://bugs.php.net/fix.php?id=34223&r=trysnapshot4
Try a CVS snapshot (php5.0): 
http://bugs.php.net/fix.php?id=34223&r=trysnapshot50
Try a CVS snapshot (php5.1): 
http://bugs.php.net/fix.php?id=34223&r=trysnapshot51
Fixed in CVS:                http://bugs.php.net/fix.php?id=34223&r=fixedcvs
Fixed in release:            http://bugs.php.net/fix.php?id=34223&r=alreadyfixed
Need backtrace:              http://bugs.php.net/fix.php?id=34223&r=needtrace
Need Reproduce Script:       http://bugs.php.net/fix.php?id=34223&r=needscript
Try newer version:           http://bugs.php.net/fix.php?id=34223&r=oldversion
Not developer issue:         http://bugs.php.net/fix.php?id=34223&r=support
Expected behavior:           http://bugs.php.net/fix.php?id=34223&r=notwrong
Not enough info:             
http://bugs.php.net/fix.php?id=34223&r=notenoughinfo
Submitted twice:             
http://bugs.php.net/fix.php?id=34223&r=submittedtwice
register_globals:            http://bugs.php.net/fix.php?id=34223&r=globals
PHP 3 support discontinued:  http://bugs.php.net/fix.php?id=34223&r=php3
Daylight Savings:            http://bugs.php.net/fix.php?id=34223&r=dst
IIS Stability:               http://bugs.php.net/fix.php?id=34223&r=isapi
Install GNU Sed:             http://bugs.php.net/fix.php?id=34223&r=gnused
Floating point limitations:  http://bugs.php.net/fix.php?id=34223&r=float
No Zend Extensions:          http://bugs.php.net/fix.php?id=34223&r=nozend
MySQL Configuration Error:   http://bugs.php.net/fix.php?id=34223&r=mysqlcfg

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