Web Mashups With Catalyst

8/14/2019 Web Mashups With Catalyst

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Web Mashups with Catalyst

Jon Allen (JJ)

http://perl.jonallen.info - [email protected]


2/23

perl.jonallen.info

The Plan

Build a blended search application using CatalystAggregate search results from:

Twitter Google Blog Search Flickr



3/23

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About Catalyst

Perl-based web framework MVC architecture Flexible URL dispatcher

Self-contained, no external file Philosophy / coding practices

DRY Dont Repeat Yourself Glue Thin Controllers / Model Wrappers Maintainability, maintainability, and maintainability



4/23

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Create the application


$ catalyst.pl MyApp

MyApp/lib/

MyApp.pmMyApp/

Model/View/Controller/

Root.pmroot/

static/

script/myapp.conf


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$ catalyst.pl MyApp

MyApp/lib/

MyApp.pmMyApp/


Root.pmroot/

static/

script/myapp.conf

Core applicationMyApp.pm

Setup, plugins,default config

Root.pmRoot controller


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perl.jonallen.info



$ catalyst.pl MyApp

MyApp/lib/

MyApp.pmMyApp/


Root.pmroot/

static/

script/myapp.conf

DataStatic files

CSS, images,JavaScript, etc

TemplatesForm definitions


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perl.jonallen.info



$ catalyst.pl MyApp

MyApp/lib/

MyApp.pmMyApp/


Root.pmroot/

static/

script/myapp.conf

ScriptsDevelopment serverProduction serverComponent creation

Models, Views,Controllers


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perl.jonallen.info



$ catalyst.pl MyApp

MyApp/lib/

MyApp.pmMyApp/


Root.pmroot/

static/

script/myapp.conf

ExtrasConfig fileTests (t/ directory)Makefile.PLDependenciesREADME / Changes


9/23

perl.jonallen.info

Install Catalyst::View::TT

Edit "lib/MyApp.pm"

Create a view


__PACKAGE__->config->{default_view} = 'TT';

__PACKAGE__->config('View::TT' => {

INCLUDE_PATH =>__PACKAGE__->path_to('root','templates'),

});

$ script/myapp_create.pl view TT TT$ mkdir root/templates


10/23

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Set up the homepage

Create "root/templates/homepage.tt" Text box that submits query to "/search"

Edit "lib/MyApp/Controller/Root.pm"


sub index :Path :Args(0) {my ( $self, $c ) = @_;

$c->stash->{template} = 'homepage.tt';}

Stash = per-requeststorage$c = Catalystcontext object

Attributes controlsURL dispatcher


11/23

perl.jonallen.info

Create a search controller


$ script/myapp_create.pl controller Search

sub index :Path :Args(0) {my ( $self, $c ) = @_;

my $q = $c->request->param('q') or do {$c->response->redirect($c->uri_for('/'));return;

};

$c->stash->{query} = $q;$c->stash->{template} = 'results.tt';$c->stash->{tweets} = $c->model('Twitter')->search($q);

$c->stash->{blogs} = $c->model('Google')->search($q);$c->stash->{photos} = $c->model('Flickr')->search($q);}

Edit "lib/MyApp/Controller/Search.pm"

"Thin Controller"no business logic


12/23

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Models

We don't have any (yet), but we have defined aninterface Single method (search), returns data structure containing

list of objects Create "root/templates/results.tt"


[% FOREACH tweet IN tweets.results %]

[% tweet.from_user %][% tweet.text %]

[% END %]

Stash availablein templates


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Model wrappers

Model = thin wrapper around an existing class Makes business logic available for use in other systems

Helper modules Catalyst::Model::Adaptor Catalyst::Model::Factory Catalyst::Model::Factory::PerRequest

Which one should you use? Depends when you want the class instantiated



14/23

perl.jonallen.info

Building the Twitter model

Net::Twitter::Search Existing module from CPAN Has a "search" method, gives the output we need


$ script/myapp_create.pl model Twitter \Adaptor Net::Twitter::Search

New Model Called "Twitter"

Use helper moduleCatalyst::Model::Adaptor Based onNet::Twitter::Search


15/23

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Twitter model done!

But we haven't written any code!All done by Catalyst::Model::Adaptor Net::Twitter::Search already has the interface we

want (search method), so it will just work



16/23

perl.jonallen.info

Creating the Google model

REST::Google::Search::Blogs Different interface, needs config (API key) We need to build our own model

Edit "lib/MyApp.pm"

Can override this in "myapp.conf"Web Mashups with Catalyst

$ script/myapp_create.pl model Google

__PACKAGE__->config('Model::Google' => {referer => 'http://yoursite.com'

});


17/23

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Coding the Google model

Edit "lib/MyApp/Model/Google.pm"


use REST::Google::Search::Blogs;

sub search {my ($self, $query) = @_;

REST::Google::Search::Blogs->http_referer($self->{referer}

);return REST::Google::Search::Blogs->new(

q => $query,rsz => 'large',

);}


18/23

perl.jonallen.info

Displaying the Google results

Edit "root/templates/results.tt"


[% FOREACH blog IN blogs.responseData.results %]

[% blog.titleNoFormatting %] by [% blog.author %]

[% blog.content %]

[% END %]


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perl.jonallen.info

Unicode

Twitter and Google APIs both return Unicode We need to enable Unicode support in Catalyst Install Catalyst::Plugin::Unicode from CPAN Edit "lib/MyApp.pm" and add "Unicode" to the list of

plugins


use Catalyst qw/ConfigLoaderStatic::SimpleUnicode

/;


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perl.jonallen.info

Flickr

Flickr::Embed Flickr::API Same concept as the Google API

Store our API key in config Create model with a "search" method to return the

results Enough code, let's see the app!



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Screenshot



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perl.jonallen.info

Summary

Catalyst is a great way to turn existing code into aweb application Mainly config, very little programming involved! Easy to extend and maintain

Models can be any source of business logic or data Not just databases!

Where possible, models should be a thin wrapperaround an external class Supports code reuse



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perl.jonallen.infoWeb Mashups with Catalyst

KTHKSBYE!

Thank you for listening!

Any questions?

http://perl.jonallen.info/talks

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Web Mashups With Catalyst