[Catalyst] Program the logic

[Nilson Santos Figueiredo Junior]

On 6/29/06, Brandon Black <blblack at gmail.com> wrote:
> The approach I'm attempting lately (and I haven't gotten it all
> working right yet...) is to make Controller base-classes that
> implement generic concepts for things like paging and sorting tables
> of data (complete with handling form args like ?page=3&count=50 or
> ?sortby=foo:desc silently for the controller), which makes it
> effortless for the controller to apply those sorts of things to the
> resultset before its sent to the view.  These bits of controller
> functionality are of course View-agnostic.

It's View-agnostic but then the View still isn't Controller-agnostic.

Actually, after some thought this might be the real question that'd
solve my issues: how to properly decouple Controller from Views?

I'll give you a real world example that's actually already in use in
an implemented (but evolving) system. I've got a somewhat generic
table widget. This table contains items that can be either active or
closed. Sometimes the closed items should be displayed along the
active, other times they shouldn't, but there's always a button
"show/hide closed items". It's currently implemented entirely in the
View, since the controller IMO shouldn't really need to know if the
closed items should or shouldn't be displayed.

That involves doing bad things such as using c.param() from the View
but it really was the only practical way (i.e. DRY) I could think of.
So, any suggestions are welcome. ;-)

> They (the base controllers implementing these features) basically boil
> down to: Check for some standardized GET form parameters, provide some
> data to the controller in the form of a paging object or some DBIC
> sorting hashref stuff, and also directly set stash variables for the
> views to see, regarding paging and sorting.  There are template
> includes that go along with these meta controller actions (displaying
> the << < 1 2 3 > >> paging clickies and whatnot, based on those stash
> vars...).

But how do you specify which actions are supposed to get the wanted behaviour?
How do you handle pages with multiple resultsets being displayed? I
think the convention could quickly become ugly. If you threw in some
AJAX stuff in the mix it might even get uglier still.

But I'd be *very, very* happy if you showed me I was wrong. ;-)

-Nilson Santos F. Jr.