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diff --git a/posts/2009-05-18-a-simple-feed-aggregator-with-modern-perl-part-4.1.md b/posts/2009-05-18-a-simple-feed-aggregator-with-modern-perl-part-4.1.md new file mode 100644 index 0000000..baeba5c --- /dev/null +++ b/posts/2009-05-18-a-simple-feed-aggregator-with-modern-perl-part-4.1.md @@ -0,0 +1,151 @@ +You can thanks [bobtfish](http://github.com/bobtfish) for being such a pedantic guy, 'cause now you will have a better chained examples. He forked my repository from GitHub and fix some code that I'll explain here. + +### lib/MyFeedReader.pm + +``` perl + package MyFeedReader; + +use Moose; + +use namespace::autoclean; + + -use strict; + -use warnings; + - + -use Catalyst::Runtime '5.70'; + +use Catalyst::Runtime '5.80'; + + -use parent qw/Catalyst/; + +extends 'Catalyst'; +``` + +You can see that he use [Moose](http://search.cpan.org/perldoc?Moose), so we can remove + +``` perl + use strict; + use warnings; +``` + +and have a more elegant way to inherit from [Catalyst](http://search.cpan.org/perldoc?Catalyst) with + +``` perl + extends 'Catalyst'; +``` + +instead of + +``` perl + use parent qw/Catalyst/; +``` + +He also have updated the **Catalyst::Runtime** version, and added **namespace::autoclean**. The purpose of this module is to keep imported methods out of you namespace. Take a look at the "documentation":<http://search.cpan.org/perldoc?namespace>::autoclean, it's easy to understand how and why it's usefull. + +### lib/MyFeedReader/Controller/Root.pm + +``` perl + -use strict; + -use warnings; + -use parent 'Catalyst::Controller'; + +use Moose; + +use namespace::autoclean; + +BEGIN { extends 'Catalyst::Controller' } + + -sub index :Path :Args(0) { + +sub root : Chained('/') PathPart() CaptureArgs(0) {} + + + +sub index : Chained('root') PathPart('') Args(0) { + my ( $self, $c ) = @_; + + # Hello World + $c->response->body( $c->welcome_message ); + } + + -sub default :Path { + +sub default : Private { + my ( $self, $c ) = @_; + $c->response->body( 'Page not found' ); + $c->response->status(404); +``` + +A new method, `root`, that will be the root path for our application. All our methods will be chained from this action. If start you catalyst server and go to \*<http://localhost:3000/*> you will be served with the Catalyst's welcome message as before. + +### lib/MyFeedReader/Controller/Entry.pm + +``` perl + -use warnings; + +use Moose; + use MyAggregator::Entry; + -use parent 'Catalyst::Controller'; + - + -__PACKAGE__->config->{namespace} = 'entry'; + +use namespace::autoclean; + +BEGIN { extends 'Catalyst::Controller'; } + + -sub view : Chained('/') : PathPart('entry') : Args(1) { + +sub view : Chained('/root') : PathPart('entry') : Args(1) { + my ( $self, $c, $id ) = @_; + + $c->stash->{entry} = $c->model('KiokuDB')->lookup($id); + } + + -1; + - + +__PACKAGE__->meta->make_immutable; +``` + +We extends the **Catalyst::Controller** in a Moose way, and the `make_immutable` instruction is a Moose recommanded best practice (you can alsa add `no Moose` after the make\_immutable). + +### lib/MyFeedreader/Controller/Feed.pm + +``` perl + +use Moose; + +use namespace::autoclean; + +BEGIN { extends 'Catalyst::Controller' } + + -use strict; + -use warnings; + -use parent 'Catalyst::Controller'; + +sub feed : Chained('/root') PathPart('feed') CaptureArgs(0) {} + + -__PACKAGE__->config->{namespace} = 'feed'; + - + -sub index : Path : Args(0) { + +sub index : Chained('feed') PathPart('') Args(0) { + my ( $self, $c ) = @_; + + $c->stash->{feeds} + = [ $c->model('MyModel')->resultset('Feed')->search() ]; + } + + -sub view : Chained('/') : PathPart('feed/view') : Args(1) { + +sub view : Chained('feed') : PathPart('view') : Args(1) { + my ( $self, $c, $id ) = @_; + + $c->stash->{feed} + = $c->model('MyModel')->resultset('Feed')->find($id); + } + + -1; + +__PACKAGE__->meta->make_immutable; +``` + +We got `feed` which is chained to root. `index` is chained to feed, and take no arguments. This method display the list of our feeds. And we got the `view` method, chained to feed too, but with one argument, that display the content of an entry. + +If you start the application, you will see the following routes: + +``` example + .-------------------------------------+--------------------------------------. + | Path Spec | Private | + +-------------------------------------+--------------------------------------+ + | /root/entry/* | /root (0) | + | | => /entry/view | + | /root/feed | /root (0) | + | | -> /feed/feed (0) | + | | => /feed/index | + | /root/feed/view/* | /root (0) | + | | -> /feed/feed (0) | + | | => /feed/view | + | /root | /root (0) | + | | => /index | + '-------------------------------------+--------------------------------------' +``` + +I hope you got a better idea about chained action in catalyst now. And again, thanks to bobtfish for the code. |