[Catalyst-dev] Plugin or controller?

[Kiki]

Matthias Dietrich wrote:
> Don't get me wrong, I don't want to create this as a plugin under all 
> circumstances.  I just want to figure out when a module is a plugin, 
> when a model and when a controller.  But I'm getting closer to the 
> truth ;).
>
> matt 
Disclaimer: IANACD (Core Developer) but here's my take.

A plugin changes fundamental functionality. By fundamental I mean mostly 
the request dispatch. For example C::P::Static skips the whole dispatch 
process, it just serves static files when the path prefix matches. And, 
as pointed out before, C::P::Authorization::* also alters the dispatch 
if the authz conditions are not matched. A plugin is loaded in the main 
app module (lib/MyApp.pm).

A controller base adds functionality. C::C::HTML::FormFu allows you to 
extend one or more of your controllers with HTML::FormFu functionality 
(displaying, processing and validating forms). C::C::RequestToken 
extends your controllers with token generating functionality. A 
controller base class is mostly used as a parent/base to the actual 
controller class and usually provides new methods to $self.

Finally, a model provides data. Be it from a database, XML feed, 
(XML)RPC, etc. it will supply data on demand. A model is accessed 
explicitly by: $c->model('MyModel'). A model's data source can (and 
sometimes will) be used outside the web framework too (from a command 
line script, cron job, etc.)

HTH