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       Catalyst::Manual::Tutorial::09_AdvancedCRUD::09_FormHandler - Catalyst
       Tutorial	- Chapter 9: Advanced CRUD - FormHandler

       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

       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.

       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/

	   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' );


   Add Action to Display and Save the Form
       At the top of the lib/MyApp/Controller/ add:

	  use MyApp::Form::Book;

       Add the following methods:

	   =head2 create

	   Use HTML::FormHandler to create a new book


	   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


	   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
		   {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:

	       <a href="[% c.uri_for(c.controller.action_for('create'))	%]">Create</a>

       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/

       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/ 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/

       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

   Create the 'edit' method
       Edit lib/MyApp/Controller/ and add the following	method:

	   =head2 edit

	   Edit	an existing book with  FormHandler


	   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:

	       [% # Add	a link to delete a book	%]
	       <a href="[% c.uri_for(c.controller.action_for('delete'),	[]) %]">Delete</a>
	       [% # Add	a link to edit a book %]
	       <a href="[% c.uri_for(c.controller.action_for('edit'), []) %]">Edit</a>

   Try Out the Edit/Update Feature
       Press "Ctrl-C" to kill the previous server instance (if it's still
       running)	and restart it:

	   $ script/

       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


	  #formhandler on

	  mailing list:


       Gerda Shank, ""

       Copyright 2009, Gerda Shank, Perl Artistic License

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