I'm building a database-backed workflow/job tasking system. The problem I'm having is that when a user goes from a main screen to the detail screen, if they hit the back button on their browser, they'll get a 'this page has expired' message.
When I set caching to private, sometimes when they go back properly (by clicking on the link) they'll get a page that's -way- old, even with cache_expire set to "0" or "1" in php.ini.
So the question would be, how do I keep the "This page has expired" screen from displaying, yet display a somewhat recent page? What determines whether a page has expired or not? The PHP manual is less than clear on these issues.
