Catalyst 5.80 - the new major version allows you lots of new ways to build applications. This talk looks at some of the technologies you may want to use, and points out some examples and other modules you might want to look at on CPAN.

1. Herding a Cat with
Antlers
New toys for writing a modern Catalyst application
Tomas Doran (t0m) <bobtfish@bobtfish.net>

2. Who am I?
(Mostly)

3. “Catalyst 5.80
Chainsaw delegate”

4. Said mst
(I’m sure he’s regretted this a time or two)

5. So, basically:
I add all the bugs..
Got it?
Great!

6. This talk
• 25% rant / ramble about Catalyst 5.80
• 50% rapid run through new Catalyst
extensions and Moose features
• 25% new developments and the future.
• NOT a Catalyst intro, sorry.

7. Theme fail
This doesn’t really fit into ‘beginning perl’.
I’ll be happy to try for ‘Beginning being a
Catalyst dev’ by handing commit bits out later

8. Catalyst 5.80
• Released April 2009
• Next major release series - 18 months
work
• 15 stable releases this year
• Backward compatible with 5.71, 5.70 etc..
• New features! Less bugs!?!

9. Moose port
• Catalyst is not designed for trivial
applications.
• Serious apps (iPlayer, rambler.ru, youporn),
serious OO. Needs a serious framework.
• Class::Accessor::Doesn’t::Cut::The::Mustard
• Antlers are awesome!!

10. Extensions!
• Catalyst is all about customisation.
• Moose Roles are much better than multiple
inheritance.
• Catalyst without CatalystX == perl5
without CPAN - not so useful.
• Getting (even) more extensible == big win.

11. Moose
• Attributes (automatically filled from config)
• Type constraints (config validation)
• Method modifiers
• Powerful delegation
• Did I mention roles?

12. Component attributes
• Models/Views/Controllers can require
attributes (with types).
• This data is supplied from config
• Access it as $self->attribute
• YES - you could do this before!

13. Component attributes

14. Delegation
• Attributes and the ‘handles’ feature are as
powerful, if not more powerful than roles.
• Delegation is often better than inheritance
or composition
• Delegate all of the methods required in an
‘interface’ role

15. Delegation

16. Roles Roles Roles
• Application class roles
• Controller roles (with method attributes)
• Request / Response roles
• Action roles
• CPAN modules to help with most of these.
• Prior art to steal!

17. Method modifiers
• Run code before / after methods, or wrap
them with around.
• Composable

18. Method modifiers

19. Another example

20. App class roles
• Things which used to be plugins can now
be roles.
• Affect things application wide as they
change the $c object.
• Useful, but don’t make a god object!

21. App class roles

22. New CPAN shiny!
• Catalyst::Controller::ActionRole
• CatalystX::RoleApplicator
• MooseX::MethodAttributes::Role
• CatalystX::Components::Traits
• Catayst::Traitfor::XXX::YYY

23. Action Roles
• Everyone has seen :ActionClass(‘RenderView’)
• You can only have 1 ActionClass
• This sucks
• Catalyst::Controller::ActionRole gives
you :Does(‘ActionRoleName’)
• (You don’t really need action classes at all)

24. Catalyst::Controller::ActionRole

25. CatalystX::RoleApplicator
• Use it in your app to apply roles to
Request/Response/Engine/Dispatcher etc
• Use it in your components/plugins rather
than monkey patching or subclassing.

26. CatalystX::RoleApplicator

27. MooseX::MethodAttributes::Role
• Controller actions can be in roles.
• Use for common path end-points (E.g.
CRUD)
• Use for common controller functionality

28. MooseX::MethodAttributes::Role

29. MooseX::MethodAttributes::Role

30. CatalystX::Components::Traits
• Apply (or remove) roles for your
application components with config.
• E.g. Change ACLs applied in different
environments.

31. CatalystX::Component:

32. Catalyst::TraitFor::XXX:YYY
• CatalystX::SimpleLogin::TraitFor::Controller::Login::WithRedirect
• Catalyst::TraitFor::Model::DBIC::Schema::Replicated
• Catalyst::TraitFor::Controller::DBIC::DoesPaging
• Don’t have to use CatalystX::Component::Traits - just roles, with
is fine if you don’t need to set them via config..

33. That’s what we did
this year!

34. This week
• I’m pleased to announce Catalyst-Runtime
5.80015 and Catalyst-Devel 1.22
• New scripts system from the Google
Summer of code.
• Moose ‘native’ application generation

35. The future
• More docs (yes, the tutorial still needs
updating)
• More deprecations (sorry!)
• Continual improvement of the 5.80XXX
series.
• Core features - Action roles? Unicode
handling?
• 5.81 - App / ctx split - branch underway

36. Thanks
Tomas Doran (t0m) <bobtfish@bobtfish.net>
#catalyst

37. Redux
• Sorry, I was lieing.
• I haven’t finished.

38. U R DOIN IT RONG
• I’ve just shown off lots of fancy tricks.
• This DOES NOT MEAN you use only
those.
• This DOES NOT MEAN all your logic
goes in Catalyst, especially not in
controllers.

39. Beware your app
getting too fat

40. CATALYST IS JUST
GLUE
• ALL of your business logic should exist
OUTSIDE CATALYST
• If you’re doing heavy lifting, it should
happen outside your web application
process.
• Your availability being AT BEST that of
remote services is a bad world.

41. This does mean
• You develop independent components
using Moose / Roles / etc
• You tie these into Catalyst as models with a
thin layer of glue.
• You reuse common workflows in Catalyst
between your apps

42. Obligatory pony