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diff --git a/posts/2009-05-13-a-simple-feed-aggregator-with-modern-perl-part-4.md b/posts/2009-05-13-a-simple-feed-aggregator-with-modern-perl-part-4.md new file mode 100644 index 0000000..c6c60ce --- /dev/null +++ b/posts/2009-05-13-a-simple-feed-aggregator-with-modern-perl-part-4.md @@ -0,0 +1,175 @@ +We have the model, the aggregator (and some tests), now we can do a basic frontend to read our feed. For this I will create a webapp using [Catalyst](http://www.catalystframework.org). + +[Catalyst::Devel](http://search.cpan.org/perldoc?Catalyst::Devel) is required for developping catalyst application, so we will install it first: + +``` perl + % cpan Catalyst::Devel +``` + +Now we can create our catalyst application using the helper: + +``` perl + % catalyst.pl MyFeedReader +``` + +This command initialise the framework for our application **MyFeedReader**. A number of files are created, like the structure of the MVC directory, some tests, helpers, ... + +We start by creating a view, using [TTSite](http://search.cpan.org/perldoc?Catalyst::View::TT). TTSite generate some templates for us, and the configuration for this template. We will also have a basic CSS, a header, footer, etc. + +``` example + cd MyFeedReader + perl script/myfeedreader_create.pl view TT TTSite +``` + +TTSite files are under **root/src** and **root/lib**. A **MyAggregator/View/TT.pm** file is also created. We edit it to make it look like this: + +``` perl + __PACKAGE__->config({ + INCLUDE_PATH => [ + MyFeedReader->path_to( 'root', 'src' ), + MyFeedReader->path_to( 'root', 'lib' ) + ], + PRE_PROCESS => 'config/main', + WRAPPER => 'site/wrapper', + ERROR => 'error.tt2', + TIMER => 0, + TEMPLATE_EXTENSION => '.tt2', + }); +``` + +Now we create our first template, in **root/src/index.tt2** + +``` example + to <a href="/feed/">your feeds</a> +``` + +If you start the application (using `perl script/myfeedreader_server.pl`) and point your browser on <http://localhost:3000/>, this template will be rendered. + +We need two models, one for KiokuDB and another one for MyModel: + +**lib/MyFeedReader/Model/KiokuDB.pm** + +``` perl + package MyFeedReader::Model::KiokuDB; + use Moose; + BEGIN { extends qw(Catalyst::Model::KiokuDB) } + 1; +``` + +we edit the configuration file (**myfeedreader.conf**), and set the dsn for our kiokudb backend + +``` example + <Model KiokuDB> + dsn dbi:SQLite:../MyAggregator/foo.db + </Model> +``` + +**lib/MyFeedReader/Model/MyModel.pm** + +``` perl + package MyFeedReader::Model::MyModel; + use base qw/Catalyst::Model::DBIC::Schema/; + 1; +``` + +and the configuration: + +``` example + <Model MyModel> + connect_info dbi:SQLite:../MyModel/model.db + schema_class MyModel + </Model> +``` + +We got our view and our model, we can do the code for the controller. We need 2 controller, one for the feed, and one for the entries. The Feed controller will list them and display entries titles for a given feed. The Entry controller will just display them. + +**lib/MyFeedReader/Controller/Feed.pm** + +``` perl + package MyFeedReader::Controller::Feed; + use strict; + use warnings; + use parent 'Catalyst::Controller'; + + __PACKAGE__->config->{namespace} = 'feed'; + + sub index : Path : Args(0) { + my ( $self, $c ) = @_; + $c->stash->{feeds} + = [ $c->model('MyModel')->resultset('Feed')->search() ]; + } + + sub view : Chained('/') : PathPart('feed/view') : Args(1) { + my ( $self, $c, $id ) = @_; + $c->stash->{feed} + = $c->model('MyModel')->resultset('Feed')->find($id); + } + + 1; +``` + +The function `index` list the feeds, while the function `view` list the entries for a give feed. We use the chained action mechanism to dispatch this url, so we can have urls like this **/feed/\*** + +We create our 2 templates (for index and view): + +**root/src/feed/index.tt2** + +``` example + <ul> + [% FOREACH feed IN feeds %] + <li><a href="/feed/view/[% feed.id %]">[% feed.url %]</a></li> + [% END %] + </ul> +``` + +**root/src/feed/vew.tt2** + +``` example + <h1>[% feed.url %]</h1> + + <h3>entries</h3> + <ul> + [% FOREACH entry IN feed.entries %] + <li><a href="/entry/[% entry.id %]">[% entry.permalink %]</a></li> + [% END %] + </ul> +``` + +If you point your browser to <http://localhost:3000/feed/> you will see this: + +Now the controller for displaying the entries: + +``` perl + package MyFeedReader::Controller::Entry; + use strict; + use warnings; + use MyAggregator::Entry; + use parent 'Catalyst::Controller'; + + __PACKAGE__->config->{namespace} = 'entry'; + + sub view : Chained('/') : PathPart('entry') : Args(1) { + my ( $self, $c, $id ) = @_; + $c->stash->{entry} = $c->model('KiokuDB')->lookup($id); + } + + 1; +``` + +The function **view** fetch an entry from the kiokudb backend, and store it in the stash, so we can use it in our template. + +**root/src/entry/view.tt2** + +``` example + <h1><a href="[% entry.permalink %]">[% entry.title %]</a></h1> + <span>Posted [% entry.date %] by [% entry.author %]</span> + <div id="content"> + [% entry.content %] + </div> +``` + +If you point your browser to an entry (something like \*<http://localhost:3000/entry/somesha256value*>), you will see an entry: + +Et voila, we are done with a really basic feed reader. You can add methods to add or delete feed, mark an entry as read, ... + +[The code is available on my git server](http://git.lumberjaph.net/p5-ironman-myfeedreader.git/). |