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diff --git a/posts/2009-05-18-a-simple-feed-aggregator-with-modern-perl-part-4.1.org b/posts/2009-05-18-a-simple-feed-aggregator-with-modern-perl-part-4.1.org new file mode 100644 index 0000000..41c5526 --- /dev/null +++ b/posts/2009-05-18-a-simple-feed-aggregator-with-modern-perl-part-4.1.org @@ -0,0 +1,169 @@ +You can thanks [[http://github.com/bobtfish][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 + +#+BEGIN_SRC 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'; +#+END_SRC + +You can see that he use [[http://search.cpan.org/perldoc?Moose][Moose]], +so we can remove + +#+BEGIN_SRC perl + use strict; + use warnings; +#+END_SRC + +and have a more elegant way to inherit from +[[http://search.cpan.org/perldoc?Catalyst][Catalyst]] with + +#+BEGIN_SRC perl + extends 'Catalyst'; +#+END_SRC + +instead of + +#+BEGIN_SRC perl + use parent qw/Catalyst/; +#+END_SRC + +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 + +#+BEGIN_SRC 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); +#+END_SRC + +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 + +#+BEGIN_SRC 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; +#+END_SRC + +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 + +#+BEGIN_SRC 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; +#+END_SRC + +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: + +#+BEGIN_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 | + '-------------------------------------+--------------------------------------' +#+END_EXAMPLE + +I hope you got a better idea about chained action in catalyst now. And +again, thanks to bobtfish for the code. |