Slides given as part of a talk for the Atlanta Perl Mongers, December 2, 2010.

1. Practical Catalyst An Introduction to a cutting edge Web Framework

2. In the beginning there was HTML <a href=”http://www.cnn.com”>CNN</a> And it was good. But it didn't change..

3. HTML was a response to the “ Tower of Babel” problem. Computers had trouble talking in ways that were independent of the operating systems and applications on which they were based. HTML and browsers were a way around that.

4. CGI – dynamic HTML With forms and content that users could interact with, the tools were built to give us things like ecommerce, web mail, etc.

6. Leonard Stein's CGI.pm

7. Templating systems

9. Jifty

10. Catalyst

12. Separation of function.

13. Let computers do more.

14. Let programmers do more with less.

17. The “A List Apart” web site.

20. Environment – Module::Starter

21. Test Harness - Test::More

22. Class Mgmt/Business Logic – Moose

23. ORM – DBIx::Class

24. Views – Templates, JSON, Email

25. Plugins to Attach Functionality

26. NonCatalyst Code -> Catalyst::Model::Adapter

29. Catalyst mailing list.

30. Perl Monks

32. Fedora – It's in the repository (older than apt-get)

33. “Definitive Guide to Catalyst” recommends vendor Perl plus local::lib plus per user CPAN install.

34. Or, install modern Perl in an alternate location and use alternate CPAN tree.

35. Starting a Project catalyst.pl ProjectName This creates a directory structure just off your home dir.

36. Model Controller “ The Cloud” Model View Model

37. A Typical Controller Method sub intro : Local { my ( $self, $c ) = @_; my $params = $c->req->params; $c->stash( current_view => 'TT' ); $c->stash( template => 'draft/intro.tt' ); }

39. Local – URL = controller name + method name

40. Private – only accessible internally

41. Path – (Literal URL)

42. Arg – Only suck down this many arguments

46. $c->response or $c->res

47. $c->log

48. $c->stash

49. $c->session

51. Take factored data and pass it to the right view.

53. Flash: longer term. Used often with the flash_to_stash config set. Useful for storage when handling forms.

54. Session: lasts some time. Can last longer than visitor's login, 2 hrs by default. Don't use same data names as stash, because they interact.

57. script/nflanalyze_create.pl model DB DBIC::Schema NflAnalyze::Schema

58. create=static components=TimeStamp,EncodedColumn

59. 'dbi:Pg:dbname=DB_NAME' 'user' 'password' '{ AutoCommit => 1 }'

61. These instantiate “has many”, “belongs to”, and “many to many” relationships.

62. Some databases better at this than others.

65. These return objects unless you export row hashes.

66. You might want to export row hashes if you're working with JSON views (broken with objects).

67. Consider letting the databases do your sorts here.

68. ResultSet returning AoH sub position_array { my ( $self, $sport_id ) = @_; my @rows = $self->search( sport_id => $sport_id, { order_by => { -asc => 'id'}} ); my @positions; for (@rows) { my %row = $_->get_columns; push @positions, row; } return positions; }

70. use parent 'Catalyst::Model';

71. use Moose;

72. use MyApp::Model::DB;

73. my $model = new MyApp::Model::DB;

74. $model->resultset('Table')->search('etc');

76. Use Catalayst::Model::Adaptor or Catalyst::Model::Factory to hook into Catalyst.

77. Advantage is the model can be tested and used outside of Catalyst (cmd line apps).

78. Typical Ajax request via jQuery function savesession() { clearstatus(); clearerror(); var lhcoll=$(&quot;#sortable&quot;).sortable(&quot;serialize&quot;); var rhcoll=$(&quot;#sortable2&quot;).sortable(&quot;serialize&quot;); var data = {}; data.ajax = 1; data.savesession = 1; data.lhcoll = lhcoll; data.rhcoll = rhcoll; jQuery.post(&quot;[% c.uri_for( c.controller.action_for('topplayer')) -%]&quot;, data, function ( hash ) { addstatus( hash.status_msg ); }, 'json' ); };

79. Catalyst Ajax dispatching my %tp_dispatch = ( savesession => 'do_save_tpl', clearsession => 'do_clear_tpl', save_db_session => 'do_save_db_tpl', load_db_session => 'do_load_db_tpl', ); # code code code if ( $params->{ajax} ) { for ( keys %tp_dispatch ) { $c->forward( $tp_dispatch{$_} ) if ( $params->{$_} ); } }

80. Output to a view (composite) if ( $params->{ajax} ) { $c->stash( current_view => 'JSON' ); } else { $c->stash( lh => $lists->{lh} ); $c->stash( rh => $lists->{rh} ); $c->stash( current_view => 'TT' ); $c->stash( template => 'draft/topplayer.tt' ); }

82. Formbuilder allows you to use a YAML file to build a form.

83. Has its own web site:

84. Because of the transition of Cat to Moose, some changes to instantiation are required now.

87. # __PACKAGE__->meta->make_immutable;

89. Tends to use short, purposeful scripts

90. Often overloaded (working @ 110%)

91. Often being asked to automate tasks formerly done through sheer numbers.

92. Often asked to provide some functions, but not all, that would normally be handled by root.

94. Scripts plus restricted shell logins.

95. Teaching power users to handle script libraries.

96. All the above require logins.

97. All the above tied to specific hardware.

98. This leads to the idea of using web interfaces as automation components

100. Better access control

101. Cross platform

102. More control over data presentation.

104. Higher order skills required

105. Presentation code can suck up time

106. Languages (php) aren't compatible with scripting tools.

108. Lower barrier of entry

109. Relatively straightforward method to take code from scripts to web tools.

110. Resultant tools can be designed to be multipurpose, both web and command line enabled.

111. Catalyst methology supports code reuse.

114. Export functionality to users.

115. Refactor as required.