Dazed & Confused

I’ve been trying to wrap my head around JAAS authentication lately. I need the container to retrieve information from LDAP in a non-standard way, especially groups.

This library supports many ways of authenticating, including Windows domains. At first glanc I can’t see if it supports LDAP, but it might be a good example to understand JAAS.

Blah, multipage forms suck. 😉 Alright, I’m not making it a lot easier for myself by insisting on using DispatchActions, but hell, it should support it.

Problem 1 – One action mapping can only have one input. This doesn’t matter when everything looks fine, but suddenly you get a validation error, and Struts tries to redirect to the first inputpage, even though the validation error occurred on page 2. With two action mappings this would of course be solved.

Problem 2 – Whenever validation fails it will redirect back to the input page. This is without touching the Action. This means that any setup you do, and things you put in the request before the page is displayed is gone. Big problem with dropdown select boxes. After failed vaildation the collection used to populate it in the request is gone and the tags fail with an Exception screaming about not finding it.

Solution – Turn off validation in the mapping and call form.validate() explicitly at the beginning of your next action step. If the validation returns errors, setup the necessary content in the request, and then forward to the page again. Not too nice. I’d rather have the Action implement a setupForm method or something.


// Validate input from previous form
ActionMessages ae = form.validate(mapping, req);
if (!ae.isEmpty()) {
this.saveErrors(req, ae);
setupStep1(req);
return mapping.getInputForward();
}


Maybe there’s some features I’m overlooking, but I’ve tried to find any info. There are lots of old posts on the mailinglists about especially problem 2, but the solution I found was to turn off validation. This seems to be an old problem, and one I have encountered several times, so I’m a bit surprised it hasn’t been incorporated into Struts yet. Or maybe it is?

Drop me a line if you have got some more info.

Update: Seems Rick Reumann has encountered the same problem here. He reaches pretty much the same conclusion as me. I’m not sure I like the solution yet, but one thing it lead me to was to structure my code better by separating out the setup code for the form in each action method.