Req #40686 [Opn]: Overly restrictive/invalid headers sent as session cache limiters

Edit report at https://bugs.php.net/bug.php?id=40686&edit=1 ID: 40686 Updated by: cmb@php.net Reported by: spam02 at pornel dot net Summary: Overly restrictive/invalid headers sent as session cache limiters Status: Open Type: Feature/Change Request -Package: Feature/Change Request +Package: *General Issues Operating System: * PHP Version: 4CVS-2007-03-01 (snap) Block user comment: N Private report: N New Comment: JFTR: the IE specific directives are removed as of PHP 7.0.0. Previous Comments: ------------------------------------------------------------------------ [2007-03-01 22:52:30] spam02 at pornel dot net Description: ------------ Currently, *by default*, PHP sends *the most restrictive* anti-caching directives possible. * no-store is intended as a security measure, not regular cache-control * must-revalidate alone doesn't prevent caching, just requires browser to revalidate it after it expires. This however, with no-cache prevents use of "offline browsing" feature. * pre-check and post-check are non-standard directives that let Internet Explorer revalidate cached objects less frequently and/or asynchronously. Please don't use these directives in the default configuration (called "nocache" cache_limiter), as their use in majority of cases is either unjustified or invalid and causes performance and usability problems (for example: https://bugzilla.mozilla.org/show_bug.cgi?id=261312). BTW: it turns out that Opera (and most likely other browser vendors) do not fully support these directives *because* PHP abuses them (http://my.opera.com/yngve/blog/2007/02/27/introducing-cache-contexts-or-why-the "This abuse is the reason why must-revalidate is only obeyed for secure sites.") Reproduce code: --------------- <?php session_start(); Expected result: ---------------- Cache-control: no-cache Actual result: -------------- Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=40686&edit=1