NAME CGI::Application::Plugin::AnyTemplate - Use any templating system from within CGI::Application using a unified interface VERSION Version 0.08 SYNOPSIS In your CGI::Application-based webapp: use base 'CGI::Application'; use CGI::Application::Plugin::AnyTemplate; sub cgiapp_init { my $self = shift; # Set template options $self->template->config( default_type => 'TemplateToolkit', ); } Later on, in a runmode: sub my_runmode { my $self = shift; my %template_params = ( name => 'Winston Churchill', age => 7, ); $self->template->fill('some_template', \%template_params); } DESCRIPTION Template-Independence "CGI::Application::Plugin::AnyTemplate" allows you to use any supported Perl templating system using a single consistent interface. Currently supported templating systems include HTML::Template, HTML::Template::Expr, Template::Toolkit and Petal. You can access any of these templating systems using the same interface. In this way, you can use the same code and switch templating systems on the fly. This approach has many uses. For instance, it can be useful in migrating your application from one templating system to another. Embedded Components In addition to template abstraction, "AnyTemplate" also provides a *embedded component mechanism*. For instance, you might include a *header* component at the top of every page and a *footer* component at the bottom of every page. These components are actually full CGI::Application run modes, and can do anything normal run mode can do, including processing form parameters and filling in their own templates. See below under "EMBEDDED COMPONENTS" for details. Multiple Named Template Configurations You can set up multiple named template configurations and select between them at run time. sub cgiapp_init { my $self = shift; # Can't use Template::Toolkit any more - # The boss wants everything has to be XML, # so we switch to Petal # Set old-style template options (legacy scripts) $self->template('oldstyle')->config( default_type => 'TemplateToolkit', TemplateToolkit => { POST_CHOMP => 1, } ); # Set new-style template options as default $self->template->config( default_type => 'Petal', auto_add_template_extension => 0, ); } sub old_style_runmode { my $self = shift; # ... # use TemplateToolkit to fill template edit_user.tmpl $self->template('oldstyle')->fill('edit_user', \%params); } sub new_style_runmode { my $self = shift; # ... # use Petal to fill template edit_user.xhml $self->template->fill('edit_user.xhtml', \%params); } Flexible Syntax The syntax is pretty flexible. Pick a style that's most comfortable for you. CGI::Application::Plugin::TT style syntax $self->template->process('edit_user', \%params); or (with slightly less typing): $self->template->fill('edit_user', \%params); CGI::Application load_tmpl style syntax my $template = $self->template->load('edit_user'); $template->param('foo' => 'bar'); $template->output; Verbose syntax (for complete control) my $template = $self->template('named_config')->load( file => 'edit_user' type => 'TemplateToolkit' add_include_path => '.', ); $template->param('foo' => 'bar'); $template->output; See also below under "CHANGING THE NAME OF THE 'template' METHOD". METHODS config Initialize the "AnyTemplate" system and provide the default configuration. $self->template->config( default_type => 'HTMLTemplate', ); You can keep multiple configurations handy at the same time by passing a value to "template": $self->template('oldstyle')->config( default_type => 'HTML::Template', ); $self->template('newstyle')->config( default_type => 'HTML::Template::Expr', ); Then in a runmode you can mix and match configurations: $self->template('oldstyle')->load # loads an HTML::Template driver object $self->template('newstyle')->load # loads an HTML::Template::Expr driver object The configuration passed to "config" is divided into three areas: *plugin configuration*, *driver configuration*, and *native configuration*: Config Type What it Configures ----------- ------------------ Plugin Config AnyTemplate itself Driver Config AnyTemplate Driver (e.g. HTMLTemplate) Native Config Actual template module (e.g. HTML::Template) These are described in more detail below. Plugin Configuration These configuration params are specific to the "CGI::Application::Plugin::AnyTemplate" itself. They are included at the top level of the configuration hash passed to "config". For instance: $self->template->config( default_type => 'HTMLTemplate', auto_add_template_extension => 0, ); The *plugin configuration* parameters and their defaults are as follows: default_type type The default type of template for this named configuration. Should be the name of a driver in the "CGI::Application::Plugin::AnyTemplate::Driver" namespace: Type Driver ---- ------ HTMLTemplate CGI::Application::Plugin::AnyTemplate::Driver::HTMLTemplate HTMLTemplateExpr CGI::Application::Plugin::AnyTemplate::Driver::HTMLTemplateExpr TemplateToolkit CGI::Application::Plugin::AnyTemplate::Driver::TemplateToolkit Petal CGI::Application::Plugin::AnyTemplate::Driver::Petal include_paths Include Paths (sometimes called search paths) are used by the various template backends to find filenames that aren't fully qualified by an absolute path. Each directory is searched in turn until the template file is found. Can be a single string or a reference to a list. auto_add_template_extension Add a template-system specific extension to template filenames. So, if this feature is enabled and you provide the filename "myfile", then the actual filename will depend on the current template driver: Driver Template ------ -------- HTMLTemplate myfile.html HTMLTemplateExpr myfile.html TemplateToolkit myfile.tmpl Petal myfile.xhtml The per-type extension is controlled by the driver config for each "AnyTemplate" driver (see below under "Driver and Native Configuration" for how to set this). The "auto_add_template_extension" feature is on by default. To disable it, pass a value of zero: $self->template->config( auto_add_template_extension => 0, ); component_handler_class Normally, component embedding is handled by CGI::Application::Plugin::AnyTemplate::ComponentHandler. If you want to use a different class for this purpose, specify the class name as the value of this paramter. It still has to provide the same interface as CGI::Application::Plugin::AnyTemplate::ComponentHandler. See the source code of that module for details. Driver and Native Configuration You can configure all the drivers at once with a single call to "config", by including subsections for each driver type: $self->template->config( default_type => 'HTMLTemplate', HTMLTemplate => { cache => 1, global_vars => 1, die_on_bad_params => 0, template_extension => '.html', }, HTMLTemplateExpr => { cache => 1, global_vars => 1, die_on_bad_params => 0, template_extension => '.html', }, TemplateToolkit => { POST_CHOMP => 1, template_extension => '.tmpl', }, Petal => { error_on_undef => 0, template_extension => '.xhtml', }, ); Each driver knows how to separate its own configuration from the configuration belonging to the underlying template system. For instance in the example above, the "HTMLTemplate" driver knows that "template_extension" is a driver config parameter, but "cache_global_vars" and "die_on_bad_params" are all HTML::Template configuration parameters. Similarly, The "TemplateToolkit" driver knows that template_extension is a driver config parameter, but "POST_CHOMP" is a "Template::Toolkit" configuration parameter. For details on driver configuration, see the docs for the individual drivers: CGI::Application::Plugin::AnyTemplate::Driver::HTMLTemplate CGI::Application::Plugin::AnyTemplate::Driver::HTMLTemplateExpr CGI::Application::Plugin::AnyTemplate::Driver::TemplateToolkit CGI::Application::Plugin::AnyTemplate::Driver::Petal Copying Query data into Templates By default, all data in "$self->query" are copied into the template object before the template is processed. For the "HTMLTemplate" and "HTMLTemplateExpr" drivers this is done with the "associate" feature of HTML::Template and HTML::Template::Expr, respectively: my $template = HTML::Template->new( associate => $self->query, ); For the other systems, this feature is emulated, by copying the query params into the template params before the template is processed. To disable this feature, pass a false value to "associate_query" or "emulate_associate_query" (depending on the template system): $self->template->config( default_type => 'HTMLTemplate', HTMLTemplate => { associate_query => 0, }, HTMLTemplateExpr => { associate_query => 0, }, TemplateToolkit => { emulate_associate_query => 0, }, Petal => { emulate_associate_query => 0, }, ); load Create a new template object and configure it. This can be as simple (and magical) as: my $template = $self->template->load; When you call "load" with no parameters, it uses the default template type, the default template configuration, and it determines the name of the template based on the name of the current run mode. If you call "load" with one paramter, it is taken to be either the filename or a reference to a string containing the template text: my $template = $self->template->load('somefile'); my $template = $self->template->load(\$some_text); If the parameter "auto_add_template_exension" is true, then the appropriate extension will be added for this template type. If you call "load" with more than one parameter, then you can specify filename and configuration paramters directly: my $template = $self->template->load( file => 'some_file.tmpl', type => 'HTMLTemplate', auto_add_template_extension => 0, add_inlcude_path => '..', HTMLTemplate => { die_on_bad_params => 1, }, ); To initialize the template from a string rather than a file, use: my $template = $self->template->load( string => \$some_text, ); The configuration parameters you pass to "load" are merged with the configuration that was passed to "config". You can include any of the configuration parameters that you can pass to config, plus the following extra parameters: file If you are loading the template from a file, then the "file" parameter contains the template's filename. string If you are loading the template from a string, then the "string" parameter contains the text of the template. It can be either a scalar or a reference to a scalar. Both of the following will work: # passing a string my $template = $self->template->load( string => $some_text, ); # passing a reference to a string my $template = $self->template->load( string => \$some_text, ); add_include_paths Additional include paths. These will be merged with "include_paths" before being passed to the template driver. The "load" method returns a template driver object. See below under "DRIVER METHODS", for how to use this object. fill Fill is a convenience method which in a single step creates the template, fills it with the template paramters and returns its output. You can call it with or without a filename (or string ref). The code: $self->template->fill('filename', \%params); is equivalent to: my $template = $self->template->load('filename'); $template->output(\%params); And the code: $self->template->fill(\$some_text, \%params); is equivalent to: my $template = $self->template->load(\$some_text); $template->output(\%params); And the code: $self->template->fill(\%params); is equivalent to: my $template = $self->template->load; $template->output(\%params); process "process" is an alias for "fill". DRIVER METHODS These are the most commonly used methods of the "AnyTemplate" driver object. The driver is what you get back from calling "$self->template->load". param The "param" method gets and sets values within the template. my $template = $self->template->load; my @param_names = $template->param(); my $value = $template->param('name'); $template->param('name' => 'value'); $template->param( 'name1' => 'value1', 'name2' => 'value2' ); It is designed to behave similarly to the "param" method in other modules like CGI and HTML::Template. get_param_hash Returns the template variables as a hash of names and values. my %params = $self->template->get_param_hash; In a scalar context, returns a reference to the hash used internally to contain the values: my $params_ref = $self->template->get_param_hash; $params_ref->{'foo'} = 'bar'; # directly change parameter 'foo' output Returns the template with all the values filled in. return $template->output; You can also supply names and values to the template at this stage: return $template->output('name' => 'value', 'name2' => 'value2'); PRE- AND POST- PROCESS Before the template output is generated, your application's "$self->template_pre_process" method is called. This method is passed a reference to the $template object. It can modify the parameters passed into the template by using the "param" method: sub template_pre_process { my ($self, $template) = @_; # Change the internal template parameters by reference my $params = $template->get_param_hash; foreach my $key (keys %$params) { $params{$key} = to_piglatin($params{$key}); } # Can also set values using the param method $template->param('foo', 'bar'); } After the template output is generated, your application's "$self->template_post_process" method is called. This method is passed a reference to the template object and a reference to the output generated by the template. You can modify this output: sub template_post_process { my ($self, $template, $output_ref) = @_; $$output_ref =~ s/foo/bar/; } When you call the "output" method, any components embedded in the template are run. See "EMBEDDED COMPONENTS", below. EMBEDDED COMPONENTS Introduction "CGI::Application::Plugin::AnyTemplate" allows you to include application components within your templates. For instance, you might include a *header* component a the top of every page and a *footer* component at the bottom of every page. These componenets are actually first-class run modes. When the template engine finds a special tag marking an embedded component, it passes control to the run mode of that name. That run mode can then do whatever a normal run mode could do. But typically it will load its own template and return the template's output. This output returned from the embedded run mode is inserted into the containing template. The syntax for embed components is specific to each type of template driver. Syntax HTML::Template syntax: HTML::Template::Expr syntax: Template::Toolkit syntax: [% CGIAPP.embed("some_run_mode") %] Petal syntax: this text gets replaced by the output of some_run_mode Getting Template Variables from the Containing Template The component run mode is passed a reference to the template object that contained the component. The component run mode can use this object to access the params that were passed to the containing template. For instance: sub header { my ($self, $containing_template, @other_params) = @_; my %tmplvars = ( 'title' => 'My glorious home page', ); my $template = $self->template->load; $template->param(%tmplvars, $containing_template->get_param_hash); return $template->output; } In this example, the template values of the enclosing template would override any values set by the embedded component. Passing Parameters The template can pass parameters to the target run mode. These are passed in after the reference to the containing template object. Parameters can either be literal strings, specified within the template text, or they can be keys that will be looked up in the template's params. Literal strings are enclosed in double or single quotes. Param keys are barewords. HTML::Template syntax: *Note that HTML::Template doesn't support this type of callback natively* *and that this behaviour is emulated by the HTMLTemplate driver* *see the docs to* CGI::Application::Plugin::AnyTemplate::Driver::HTMLTemplate *for limitations to the emulation*. HTML::Template::Expr syntax: Template::Toolkit syntax: [% CGIAPP.embed("some_run_mode", param1, 'literal string2' ) %] Petal syntax: this text gets replaced by the output of some_run_mode CHANGING THE NAME OF THE 'template' METHOD If you want to access the features of this module using a method other than "template", you can do so via Anno Siegel's Exporter::Renaming module (available on CPAN). For instance, to use syntax similar to CGI::Application::Plugin::TT: use Exporter::Renaming; use CGI::Application::Plugin::AnyTemplate Renaming => [ template => tt]; sub cgiapp_init { my $self = shift; my %params = ( ... ); # Set config file and other options $self->tt->config( default_type => 'TemplateToolkit', ); } sub my_runmode { my $self = shift; $self->tt->process('file', \%params); } And to use syntax similar to CGI::Application's "load_tmpl" mechanism: use Exporter::Renaming; use CGI::Application::Plugin::AnyTemplate Renaming => [ template => tmpl]; sub cgiapp_init { my $self = shift; # Set config file and other options $self->tmpl->config( default_type => 'HTMLTemplate', ); } sub my_runmode { my $self = shift; my %params = ( ... ); my $template = $self->tmpl->load('file'); $template->param(\%params); $template->output; } AUTHOR Michael Graham, "" ACKNOWLEDGEMENTS I originally wrote this to be a subsystem in Richard Dice's CGI::Application-based framework, before I moved it into its own module. Various ideas taken from CGI::Application (Jesse Erlbaum), CGI::Application::Plugin::TT (Cees Hek) and "Text::Boilerplate" (Stephen Nelson). "Template::Toolkit" singleton support code stolen from CGI::Application::Plugin::TT. BUGS Please report any bugs or feature requests to "bug-cgi-application-plugin-anytemplate@rt.cpan.org", or through the web interface at . I will be notified, and then you'll automatically be notified of progress on your bug as I make changes. SEE ALSO CGI::Application::Plugin::AnyTemplate::Base CGI::Application::Plugin::AnyTemplate::ComponentHandler CGI::Application::Plugin::AnyTemplate::Driver::HTMLTemplate CGI::Application::Plugin::AnyTemplate::Driver::HTMLTemplateExpr CGI::Application::Plugin::AnyTemplate::Driver::TemplateToolkit CGI::Application::Plugin::AnyTemplate::Driver::Petal CGI::Application Template::Toolkit HTML::Template Petal Exporter::Renaming CGI::Application::Plugin::TT COPYRIGHT & LICENSE Copyright 2005 Michael Graham, All Rights Reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.