The temp folder is a “nonundoing” storage (meaning you cannot undo transactions which take place within it) because accesses to transient data containers are very write-intensive, and undoability adds unnecessary overhead.
However, if you simply visit some other pages and then return within 20 minutes or so, it still remembers the last time you viewed it.
See the section at the end of this document for things to watch out for while accessing Zope’s Session Manager “naively”.
When a session data object is invalidated, it will be flushed from the system. If you invalidate the session object in a script then you must obtain a fresh copy of the session object by calling get Session Data and not by reference (REQUEST. Here is an example using DTML:: Manual invalidation of session data is useful when you need a “fresh” copy of a session data object.
If an “on Delete” event is defined for a session data object, the on Delete method will be called before the data object is invalidated.
You can use sessions in Page Templates and DTML Documents, too.