[Catalyst] Cascading action dispatching

[John Napiorkowski]

--- Matt S Trout <dbix-class at trout.me.uk> wrote:

> On Tue, Oct 23, 2007 at 07:40:36AM -0700, John
> Napiorkowski wrote:
> > 
> > --- Matt S Trout <dbix-class at trout.me.uk> wrote:
> > 
> > > On Sun, Oct 21, 2007 at 10:20:20AM -0400,
> Matthew
> > > Pitts wrote:
> > > > On Fri, 2007-10-19 at 17:16 -0400, Matthew
> Pitts
> > > wrote:
> > > > > 
> > > > > I'm trying to figure out a way to have my
> Cat
> > > app dispatch in a way
> > > > > that
> > > > > would allow multiple actions in the same
> > > namespace and have them
> > > > > called
> > > > > in succession until one of them actually
> handles
> > > the request.
> > > > > 
> > > > > I have a client that really likes base-level
> > > URLs, like
> > > > > "/shoppingmallxyz", and wants to use them
> for
> > > landing pages that are
> > > > > functionally different. In some of these
> cases
> > > the base-level URL
> > > > > paths
> > > > > are really just monikers for things that are
> > > retrieved from the DB and
> > > > > if it exists, then a page is rendered.
> > > > 
> > > > I guess another, maybe more elegant, way to
> > > accomplish this same effect
> > > > would be to override register_actions in the
> > > Controllers where I want to
> > > > do this and have a call to a
> > > register_dynamic_actions method like so:
> > > > 
> > > > package MyApp::Controller::Center;
> > > > 
> > > > sub register_actions {
> > > >     my $self = shift;
> > > >     my ( $c ) = @_;
> > > > 
> > > >     $self->register_dynamic_actions($c);
> > > > 
> > > >     return $self->SUPER::register_actions(@_);
>   
> > > # or NEXT?
> > > > }
> > > > 
> > > > sub register_dynamic_actions {
> > > >     my $self = shift;
> > > >     my ( $c ) = @_;
> > > > 
> > > >     my $centers = $c->model('Center')->all;
> > > > 
> > > >     while ( my $center = $centers->next ) {
> > > >         my $action =
> $self->create_action(...);
> > > >         $c->dispatcher->register($c, $action);
> > > >     }
> > > > }
> > > > 
> > > > 1;
> > > > 
> > > > An obvious side-effect (AFAIK) of doing it
> this
> > > way is that the app has
> > > > to be restarted for new dynamic actions to
> take
> > > affect. The benefit,
> > > > however, is that the root-level pseudo-actions
> I
> > > was trying to achieve
> > > > with on-the-fly DB lookups are now first class
> > > actions and would not
> > > > require a DB call on each request.
> > > > 
> > > > I may be crazy... anybody got any thoughts on
> > > this?
> > > 
> > > Yes, you're crazy.
> > > 
> > > OTOH you appear to be the same same sort of
> crazy I
> > > was when I wrote
> > > register_actions and intentionally factored the
> > > process in such a way
> > > that it was overridable, so don't let that stop
> you
> > > implementing this.
> > > 
> > > The only better solution I can think of is to
> handle
> > > whether you accept the
> > > action via an action class, but we need to add a
> > > $action->match_captures for
> > > chain mid-points to make that elegant, currently
> you
> > > only get a match on the
> > > end point which would be a bit messy to
> implement.
> > > 
> > > I plan to add such a method for 5.80
> > 
> > Matt,
> > 
> > I actually started playing with this a few months
> ago
> > (wrote some tests for the expected behavior, etc)
> but
> > had a little trouble getting it to work correctly.
> 
> > Did you actually start on this?  Because if you
> have a
> > plan I would be happen to be the implementation
> > monkey.  --John
> 
> You'd need to build up the ActionChain object so
> when you call match_captures
> on $midpoint_action it sees the rest of the actions
> already in the chain.
> 
> If you fancy throwing up a 5.80 branch and putting
> in your tests I can have
> a dig around, I really doing think the
> implementation will be much work.

I'll give it a shot.  I really think this is something
needed.  I'll set it up (after I get you that DBIC
patch I still owe, regarding that bytea problem ;)

--john

> 
> -- 
>       Matt S Trout       Need help with your
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