[Catalyst] Dispatching based on path and host/domain

[Curtis Fletcher]

Hi again guys.

I've got a moderate sized Catalyst App in production now which I'm
almost happy with :)
It responds to one domain at the moment, and I'm pondering how to break
out into two or more doing mostly the same thing on the same codebase
and hopefully the same app instance.

The app has a few "usual" controllers that handle specifics like the
e-commerce, admin and soon, some database product access stuff. Any URI
that fails to match a action defaults to the root controller and is then
stripped and handled with a few calls to my model which builds the
closest page from CMS style content.

E.G.

http://mydomain.com/cart/view
Ends up calling the Local "view" method of myapp::Controller::Cart as
you might expect but
http://mydomain.com/businessunit1/product1/specialofferpage

Ends up in the root controller and queries tables that holds dynamic
URI-to-page content object mappings which then uses common code to
render the page

So for the CMS style data, if I add another domain "mydomain2" to the
apache config for my myapp and another field to the UriPage table for
"domain" and I'm almost there.
But I'm at a bit of a loss at to what to do about:
http://mydomain2.com/cart/view
Ending up at myapp::Controller::Cart->view because that domain isn't
supposed to have the e-commerce bit.

I've been pondering how to make this distinction, maybe there is
something I could get the dispatcher to do like:

package myapp::Controller::Cart;

sub view : Local Domain('mydomain.com')
{
}

Or something with the namespaces so that 
http://mydomain.com/cart/view got mapped to
myapp::mydomain::Controller::Cart->view and
http://mydomain2.com/search got mapped to
myapp::mydomain2::Controller::Search

still making sure that anything that didn't match still ended up in the
root controller unmangled.

What I think I'd like if to be able to do is opt a namespace out of a
particular domain's dispatcher
Something like:
__PACKAGE__->config->{'opt_out'}->
{
	'mydomain2.com' => ['/cart',],
	'mydomain.com' => ['/search',],
}

That way common actions still work on both domains. Worst comes to the
worst I'll set config options that disable methods based on ENV
variables then run two app instances on the same codebase but I'd prefer
to avoid that.

Is this approach even sane? any suggestions/pointers/thoughts are
welcomed.