[Seaside] expiring pages

[Avi Bryant]

On Jul 18, 2004, at 3:47 PM, radoslav hodnicak wrote:

> I'm doing a sort of hierarchy/tree editor (it just displays boxes
> connected with lines) and for some actions, I want to set the previous
> pages as expired, so that the user can't use the back button to change
> things.
>
> I know about session isolate: [] but I can't quite figure out how to 
> use
> it here. This is seaside 2.3. The component works like
>
> -render all nodes
> -action to add/delete node
> -repeat until save/cancel
>
> So for example after the user deletes a node I want to make the 
> previous
> pages expired so that they can't go back and work with the deleted 
> node.

This sounds like a variation on #once:, which will expire each page 
immediately - you'd want to wrap it around the call to your editor 
component, so,

self session once: [self call: HierarchyEditor new].

But that wouldn't do quite what you want, since you only want the 
expiry to happen after certain actions.  So I think you need to 
implement your own filter, using WAOnce as an example.  Unlike WAOnce, 
which records all the actionKeys it sees and then complains if it ever 
sees them a second time, you'd want to keep a list of "expiredKeys", 
and a list of "currentKeys", and have some message telling it to move 
all the currentKeys into the expired list, that would be sent after 
node deletion etc.

This is probably a common enough requirement that a filter/decoration 
like this should be in the base.  So let us know how it goes.

Avi