NAME

CGI::Application::Plugin::AnyTemplate::Driver::TemplateToolkit - Template::Toolkit plugin to AnyTemplate

DESCRIPTION

This is a driver for CGI::Application::Plugin::AnyTemplate, which provides the implementation details specific to rendering templates via the Template::Toolkit templating system.

All "AnyTemplate" drivers are designed to be used the same way. For general usage instructions, see the documentation of CGI::Application::Plugin::AnyTemplate.

EMBEDDED COMPONENT SYNTAX (Template::Toolkit)

The Template::Toolkit syntax for embedding components is:

    [% CGIAPP.embed("some_run_mode", param1, param2, 'literal string3') %]

This can be overridden by the following configuration variables:

    embed_tag_name       # default 'CGIAPP'

For instance by setting the following values in your configuration file:

    embed_tag_name       'MYAPP'

Then the embedded component tag will look like:

    [% MYAPP.embed("some_run_mode") %]

TT OBJECT CACHING (singleton support)

Introduction

In a persistent environment, rather than creating a Template::Toolkit object each time you fill a template, it is much more efficient to load a single Template::Toolkit object and use this object to render all of your templates.

However, in a persistent environment, you may have several different applications running, and they all might need to set different Template::Toolkit options (such as "POST_CHOMP", etc.).

By default, when the "TemplateToolkit" driver creates a Template::Toolkit object, it caches it. From that point on, whenever the same application needs a Template::Toolkit object, the driver uses the cached object rather than creating a new one.

Multiple Applications in a Shared Persistent Environment

An attempt is made to prevent different applications from sharing the same TT object.

Internally, the TT objects are stored in a private hash keyed by the web application's class name.

You can explicitly specify the class name when you call "config":

        $self->template->config(
            type          => 'TemplateToolkit',
            TemplateToolkit => {
                storage_class => 'My::Project',
            },
        );

If you don't specify the class name, then the package containing the subroutine that called "config" is used. For instance:

    package My::Project;
    sub setup {
        my $self = shift;
        $self->template->config(                 # My::Project is used to store
            type          => 'TemplateToolkit',  # cached TT object
        );
    }

A typical "CGI::Application" module hierarchy looks like this:

    CGI::Application
        My::Project
            My::Webapp

In this hierarchy, it makes sense to store the cached TT object in "My::Project". To make this happen, either call "$self->template->config" from within "My::Project", or explicitly name the "storage_class" when you call "$self->template->config".

Disabling TT Object Caching

You can disable Template::Toolkit object caching entirely by providing a false value to the "object_caching" driver config parameter:

        $self->template->config(
            type          => 'TemplateToolkit',
            TemplateToolkit => {
                object_caching => 0,
            },
        );

TT Object Caching and Include Paths

The "include_paths" driver config parameter is not cached; it is set every time you call "$self->template->load". So you can safely used cached TT objects even if the applications sharing the TT object need different "include_paths".

CONFIGURATION

The CGI::Application::Plugin::AnyTemplate::Driver::TemplateToolkit driver accepts the following config parameters:

embed_tag_name

The name of the tag used for embedding components. Defaults to "CGIAPP".

template_extension

If "auto_add_template_extension" is true, then CGI::Application::Plugin::AnyTemplate will append the value of "template_extension" to "filename". By default the "template_extension" is ".xhtml".

emulate_associate_query

This feature is now deprecated and will be removed in a future release.

If this config parameter is true, then CGI::Application::Plugin::AnyTemplate::Driver::TemplateToolkit will copy all of the webapp's query params into the template.

This is similar to what would happen if you used HTML::Template's "associate" feature with the webapp's query object:

    my $driver = HTML::Template->new(
        associate => $self->query,
    );

By default "emulate_associate_query" is false.

object_caching

Whether or not to cache the Template::Toolkit object in a persistent environment

By default, "object_caching" is enabled.

See "TT OBJECT CACHING (singleton support)", above.

storage_class

What class to use as the storage key when object caching is enabled.

By default, "storage_class" defaults to the package containing the subroutine that called "$self->template->config".

See "TT OBJECT CACHING (singleton support)", above.

All other configuration parameters are passed on unchanged to Template::Toolkit.

CONFIGURING UTF-8 TEMPLATES

"AnyTemplate" does NOT support Template::Toolkit's "binmode" option at runtime:

    # not possible with AnyTemplate
    $tt->process($infile, $vars, $outfile, { binmode => 1 })
        || die $tt->error(), "\n";
    
    # not possible with AnyTemplate
    $tt->process($infile, $vars, $outfile, binmode => 1)
        || die $tt->error(), "\n";
    
    # not possible with AnyTemplate
    $tt->process($infile, $vars, $outfile, binmode => ':utf8')
        || die $tt->error(), "\n";

Instead, use the "ENCODING" option in the initial config:

    $self->template->config(
        default_type => 'TemplateToolkit',
        TemplateToolkit => { 
            ENCODING => 'UTF-8' 
        }
    );

If you have a mix of encodings in your templates, use a separate "AnyTemplate" configuration for each encoding:

    $self->template('ascii')->config(
        default_type => 'TemplateToolkit',
    );
    $self->template('utf-8')->config(
        default_type => 'TemplateToolkit',
        TemplateToolkit => { 
            ENCODING => 'UTF-8' 
        }
    );

required_modules

The "required_modules" function returns the modules required for this driver to operate. In this case: "Template".

DRIVER METHODS

initialize

Initializes the "TemplateToolkit" driver. See the docs for CGI::Application::Plugin::AnyTemplate::Base for details.

render_template

Fills the Template::Toolkit object with "$self->param"

If the param "emulate_associate_query" is true, then set params for each of $self->{'webapp'}->query, mimicking HTML::Template's associate mechanism.

Also set up a CGI::Application::Plugin::AnyTemplate::ComponentHandler object so that the "CGIAPP.embed" callback will work.

Returns the output of the filled template as a string reference.

See the docs for CGI::Application::Plugin::AnyTemplate::Base for details.

ACKNOWLEDGEMENTS

Thanks to Cees Hek for discussing the issues of caching in a persistent environment. And also for his excellent CGI::Application::Plugin::TT module, from which I stole ideas and some code: especially the bit about how to change the include path in a TT object after you've initialized it.

AUTHOR

Michael Graham, "<mgraham@cpan.org>"

COPYRIGHT & LICENSE

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.