NAME

CGI::FormBuilder::Template - Template adapters for FormBuilder

SYNOPSIS

# Define a template engine
package CGI::FormBuilder::Template::Whatever;
use base 'Whatever::Template::Module';
sub new {
    my $self  = shift;
    my $class = ref($self) || $self;
    my %opt   = @_;
    # override some options
    $opt{some_setting} = 0;
    $opt{another_var}  = 'Some Value';
    # instantiate the template engine
    $opt{engine} = Whatever::Template::Module->new(%opt);
    return bless \%opt, $class;
}
sub render {
    my $self = shift;
    my $form = shift;   # only arg is form object
    # grab any manually-set template params
    my %tmplvar = $form->tmpl_param;
    # example template manipulation
    my $html = $self->{engine}->do_template(%tmplvar);
    return $html;       # scalar HTML is returned
}

DESCRIPTION

This documentation describes the usage of FormBuilder templates, as well as how to write your own template adapter.

The template engines serve as adapters between CPAN template modules and FormBuilder. A template engine is invoked by using the "template" option to the top-level new() method:

my $form = CGI::FormBuilder->new(
                template => 'filename.tmpl'
           );

This example points to a filename that contains an "HTML::Template" compatible template to use to layout the HTML. You can also specify the "template" option as a reference to a hash, allowing you to further customize the template processing options, or use other template engines.

For example, you could turn on caching in "HTML::Template" with something like the following:

my $form = CGI::FormBuilder->new(
                fields => \@fields,
                template => {
                    filename => 'form.tmpl',
                    shared_cache => 1
                }
           );

As mentioned, specifying a hashref allows you to use an alternate template processing system like the "Template Toolkit". A minimal configuration would look like this:

my $form = CGI::FormBuilder->new(
                fields => \@fields,
                template => {
                    type => 'TT2',      # use Template Toolkit
                    template => 'form.tmpl',
                },
           );

The "type" option specifies the name of the engine. Currently accepted types are:

Builtin -  Included, default rendering if no template specified
Div     -  Render form using <div> (no tables)
HTML    -  HTML::Template
Text    -  Text::Template
TT2     -  Template Toolkit
Fast    -  CGI::FastTemplate
CGI_SSI -  CGI::SSI

In addition to one of these types, you can also specify a complete package name, in which case that module will be autoloaded and its new() and render() routines used. For example:

my $form = CGI::FormBuilder->new(
                fields => \@fields,
                template => {
                    type => 'My::Template::Module',
                    template => 'form.tmpl',
                },
           );

All other options besides "type" are passed to the constructor for that templating system verbatim, so you'll need to consult those docs to see what all the different options do. Skip down to "SEE ALSO".

SUBCLASSING TEMPLATE ADAPTERS

In addition to the above included template engines, it is also possible to write your own rendering module. If you come up with something cool, please let the mailing list know!

To do so, you need to write a module which has a sub called render(). This sub will be called by FormBuilder when "$form->render" is called. This sub can do basically whatever it wants, the only thing it has to do is return a scalar string which is the HTML to print out.

This is actually not hard. Here's a simple adapter which would manipulate an "HTML::Template" style template:

# This file is My/HTML/Template.pm
package My::HTML::Template;
use CGI::FormBuilder::Template::HTML;
use base 'CGI::FormBuilder::Template::HTML';
sub render {
    my $self = shift;    # class object
    my $form = shift;    # $form as only argument
    # the template object (engine) lives here
    my $tmpl = $self->engine;
    # setup vars for our fields (objects)
    for ($form->field) {
        $tmpl->param($_ => $_->value);
    }
    # render output
    my $html = $tmpl->output;
    # return scalar;
    return $html;
}
1;  # close module

Then in FormBuilder:

use CGI::FormBuilder;
use My::HTML::Template;   # your module
my $tmpl = My::HTML::Template->new;
my $form = CGI::FormBuilder->new(
                fields   => [qw(name email)],
                header   => 1,
                template => $tmpl   # pass template object
           );
# set our company from an extra CGI param
my $co = $form->cgi_param('company');
$tmpl->engine->param(company => $co);
# and render like normal
print $form->render;

That's it! For more details, the best thing to do is look through the guts of one of the existing template engines and go from there.

REVISION

$Id: Template.pm 97 2007-02-06 17:10:39Z nwiger $

AUTHOR

This module is free software; you may copy this under the terms of the GNU General Public License, or the Artistic License, copies of which should have accompanied your Perl kit.

2023-07-25

perl v5.38.0