Provided by: libcatalyst-manual-perl_5.9009-1_all 
NAME
Catalyst::Manual::Tutorial::09_AdvancedCRUD::09_FormHandler - Catalyst Tutorial - Chapter
9: Advanced CRUD - FormHandler
OVERVIEW
This is Chapter 9 of 10 for the Catalyst tutorial.
Tutorial Overview
1. Introduction
2. Catalyst Basics
3. More Catalyst Basics
4. Basic CRUD
5. Authentication
6. Authorization
7. Debugging
8. Testing
9. 09_Advanced CRUD::09_FormHandler
10. Appendices
DESCRIPTION
This portion of the tutorial explores HTML::FormHandler and how it can be used to manage
forms, perform validation of form input, and save and restore data to or from the
database. This was written using HTML::FormHandler version 0.28001.
See Catalyst::Manual::Tutorial::09_AdvancedCRUD for additional form management options
other than HTML::FormHandler.
Install HTML::FormHandler
Use the following command to install HTML::FormHandler::Model::DBIC directly from CPAN:
sudo cpan HTML::FormHandler::Model::DBIC
It will install HTML::FormHandler as a prerequisite.
Also, add:
requires 'HTML::FormHandler::Model::DBIC';
to your "Makefile.PL".
HTML::FormHandler FORM CREATION
This section looks at how HTML::FormHandler can be used to add additional functionality to
the manually created form from Chapter 4.
Using FormHandler in your controllers
FormHandler doesn't have a Catalyst base controller, because interfacing to a form is only
a couple of lines of code.
Create a Book Form
Create the directory "lib/MyApp/Form". Create "lib/MyApp/Form/Book.pm":
package MyApp::Form::Book;
use HTML::FormHandler::Moose;
extends 'HTML::FormHandler::Model::DBIC';
use namespace::autoclean;
has '+item_class' => ( default =>'Books' );
has_field 'title';
has_field 'rating' => ( type => 'Integer' );
has_field 'authors' => ( type => 'Multiple', label_column => 'last_name' );
has_field 'submit' => ( type => 'Submit', value => 'Submit' );
__PACKAGE__->meta->make_immutable;
1;
Add Action to Display and Save the Form
At the top of the "lib/MyApp/Controller/Books.pm" add:
use MyApp::Form::Book;
Add the following methods:
=head2 create
Use HTML::FormHandler to create a new book
=cut
sub create : Chained('base') PathPart('create') Args(0) {
my ($self, $c ) = @_;
my $book = $c->model('DB::Book')->new_result({});
return $self->form($c, $book);
}
=head2 form
Process the FormHandler book form
=cut
sub form {
my ( $self, $c, $book ) = @_;
my $form = MyApp::Form::Book->new;
# Set the template
$c->stash( template => 'books/form.tt2', form => $form );
$form->process( item => $book, params => $c->req->params );
return unless $form->validated;
# Set a status message for the user & return to books list
$c->response->redirect($c->uri_for($self->action_for('list'),
{mid => $c->set_status_msg("Book created")}));
}
These two methods could be combined at this point, but we'll use the 'form' method later
when we implement 'edit'.
Create a Template Page To Display The Form
Open "root/src/books/form.tt2" in your editor and enter the following:
[% META title = 'Create/Update Book' %]
[%# Render the HTML::FormHandler Form %]
[% form.render %]
<p><a href="[% c.uri_for(c.controller.action_for('list')) %]">Return to book list</a></p>
Add Link for Create
Open "root/src/books/list.tt2" in your editor and add the following to the bottom of the
existing file:
...
<p>
HTML::FormHandler:
<a href="[% c.uri_for(c.controller.action_for('create')) %]">Create</a>
</p>
This adds a new link to the bottom of the book list page that we can use to easily launch
our HTML::FormHandler-based form.
Test The HTML::FormHandler Create Form
Press "Ctrl-C" to kill the previous server instance (if it's still running) and restart
it:
$ script/myapp_server.pl
Login as "test01" (password: mypass). Once at the Book List page, click the new
HTML::Formhandler "Create" link at the bottom to display the form. Fill in the following
values:
Title = "Internetworking with TCP/IP Vol. II"
Rating = "4"
Author = "Comer"
Click the Submit button, and you will be returned to the Book List page with a "Book
created" status message displayed.
Note that because the 'Author' column is a Select list, only the authors in the database
can be entered. The 'ratings' field will only accept integers.
Add Constraints
Open "lib/MyApp/Form/Book.pm" in your editor.
Restrict the title size and make it required:
has_field 'title' => ( minlength => 5, maxlength => 40, required => 1 );
Add range constraints to the 'rating' field:
has_field 'rating' => ( type => 'Integer', range_start => 1, range_end => 5 );
The 'authors' relationship is a 'many-to-many' pseudo-relation, so this field can be set
to Multiple to allow the selection of multiple authors; also, make it required:
has_field 'authors' => ( type => 'Multiple', label_column => 'last_name',
required => 1 );
Note: FormHandler automatically strips whitespace at the beginning and end of fields. If
you want some other kind of stripping (or none) you can specify it explicitly; see
HTML::FormHandler::Manual.
Try Out the Updated Form
Press "Ctrl-C" to kill the previous server instance (if it's still running) and restart
it:
$ script/myapp_server.pl
Make sure you are still logged in as "test01" and try adding a book with various errors:
title less than 5 characters, non-numeric rating, a rating of 0 or 6, etc. Also try
selecting one, two, and zero authors.
Create the 'edit' method
Edit "lib/MyApp/Controller/Books.pm" and add the following method:
=head2 edit
Edit an existing book with FormHandler
=cut
sub edit : Chained('object') PathPart('edit') Args(0) {
my ( $self, $c ) = @_;
return $self->form($c, $c->stash->{object});
}
Update the "root/src/books/list.tt2", adding an 'edit' link below the "Delete" link to use
the FormHandler edit method:
<td>
[% # Add a link to delete a book %]
<a href="[% c.uri_for(c.controller.action_for('delete'), [book.id]) %]">Delete</a>
[% # Add a link to edit a book %]
<a href="[% c.uri_for(c.controller.action_for('edit'), [book.id]) %]">Edit</a>
</td>
Try Out the Edit/Update Feature
Press "Ctrl-C" to kill the previous server instance (if it's still running) and restart
it:
$ script/myapp_server.pl
Make sure you are still logged in as "test01" and go to the
<http://localhost:3000/books/list> URL in your browser. Click the "Edit" link next to
"Internetworking with TCP/IP Vol. II", change the rating to a 3, the "II" at end of the
title to the number "2", add Stevens as a co-author (control-click), and click Submit.
You will then be returned to the book list with a "Book edited" message at the top in
green. Experiment with other edits to various books.
See additional documentation on FormHandler
HTML::FormHandler::Manual
HTML::FormHandler
#formhandler on irc.perl.org
mailing list: http://groups.google.com/group/formhandler
code: http://github.com/gshank/html-formhandler/tree/master
AUTHOR
Gerda Shank, "gshank@cpan.org"
Copyright 2009, Gerda Shank, Perl Artistic License
perl v5.20.2 Catalyst::Manual::Tutorial::09_AdvancedCRUD::09_FormHandler(3pm)