NAME¶
CGI::Application::Plugin::TT - Add Template Toolkit support to CGI::Application
SYNOPSIS¶
use base qw(CGI::Application);
use CGI::Application::Plugin::TT;
sub myrunmode {
my $self = shift;
my %params = (
email => 'email@company.com',
menu => [
{ title => 'Home', href => '/home.html' },
{ title => 'Download', href => '/download.html' },
],
session_obj => $self->session,
);
return $self->tt_process('template.tmpl', \%params);
}
DESCRIPTION¶
CGI::Application::Plugin::TT adds support for the popular Template Toolkit
engine to your CGI::Application modules by providing several helper methods
that allow you to process template files from within your runmodes.
It compliments the support for HTML::Template that is built into
CGI::Application through the
load_tmpl method. It also provides a few
extra features than just the ability to load a template.
METHODS¶
tt_process¶
This is a simple wrapper around the Template Toolkit process method. It accepts
zero, one or two parameters; an optional template filename, and an optional
hashref of template parameters (the template filename is optional, and will be
autogenerated by a call to $self->tt_template_name if not provided). The
return value will be a scalar reference to the output of the template.
package My::App::Browser
sub myrunmode {
my $self = shift;
return $self->tt_process( 'Browser/myrunmode.tmpl', { foo => 'bar' } );
}
sub myrunmode2 {
my $self = shift;
return $self->tt_process( { foo => 'bar' } ); # will process template 'My/App/Browser/myrunmode2.tmpl'
}
tt_config¶
This method can be used to customize the functionality of the
CGI::Application::Plugin::TT module, and the Template Toolkit module that it
wraps. The recommended place to call "tt_config" is as a class
method in the global scope of your module (See SINGLETON SUPPORT for an
explanation of why this is a good idea). If this method is called after a call
to tt_process or tt_obj, then it will die with an error message.
It is not a requirement to call this method, as the module will work without any
configuration. However, most will find it useful to set at least a path to the
location of the template files ( or you can set the path later using the
tt_include_path method).
our $TEMPLATE_OPTIONS = {
COMPILE_DIR => '/tmp/tt_cache',
DEFAULT => 'notfound.tmpl',
PRE_PROCESS => 'defaults.tmpl',
};
__PACKAGE__->tt_config( TEMPLATE_OPTIONS => $TEMPLATE_OPTIONS );
The following parameters are accepted:
- TEMPLATE_OPTIONS
- This allows you to customize how the Template object is created by
providing a list of options that will be passed to the Template
constructor. Please see the documentation for the Template module for the
exact syntax of the parameters, or see below for an example.
- TEMPLATE_NAME_GENERATOR
- This allows you to provide your own method for auto-generating the
template filename. It requires a reference to a function that will be
passed the $self object as it's only parameter. This function will be
called everytime $self->tt_process is called without providing the
filename of the template to process. This can standardize the way
templates are organized and structured by making the template filenames
follow a predefined pattern.
The default template filename generator uses the current module name, and
the name of the calling function to generate a filename. This means your
templates are named by a combination of the module name, and the
runmode.
- TEMPLATE_PRECOMPILE_DIR
- This options allows you to specify a directory (or an array of
directories) to search when this module is loaded and then compile all
files found into memory. This provides a speed boost in persistent
environments (mod_perl, fast-cgi) and can improve memory usage in
environments that use shared memory (mod_perl).
- TEMPLATE_PRECOMPILE_FILETEST
- This option allows you to specify exactly which files will get compiled
when using the TEMPLATE_PRECOMPILE_DIR option. You can provide it with one
of 3 different variable types:
- STRING
- A filename extension that can specify what type of files will be loaded
(eg 'tmpl').
- REGEXP
- Filenames that match the regular expression will be precompiled ( eg
qr/\.(tt|tmpl|html)$/ ).
- CODEREF
- A code reference that will be called once for each filename and directory
found, and if it returns true, the template will be precompiled (eg sub {
my $file = shift; ... } ).
tt_obj¶
This method will return the underlying Template Toolkit object that is used
behind the scenes. It is usually not necessary to use this object directly, as
you can process templates and configure the Template object through the
tt_process and tt_config methods. Every call to this method will return the
same object during a single request.
It may be useful for debugging purposes.
tt_params¶
This method will accept a hash or hashref of parameters that will be included in
the processing of every call to tt_process. It is important to note that the
parameters defined using tt_params will be passed to every template that is
processed during a given request cycle. Usually only one template is processed
per request, but it is entirely possible to call tt_process multiple times
with different templates. Everytime tt_process is called, the hashref of
parameters passed to tt_process will be merged with the parameters set using
the tt_params method. Parameters passed through tt_process will have
precidence in case of duplicate parameters.
This can be useful to add global values to your templates, for example passing
the user's name automatically if they are logged in.
sub cgiapp_prerun {
my $self = shift;
$self->tt_params(username => $ENV{REMOTE_USER}) if $ENV{REMOTE_USER};
}
tt_clear_params¶
This method will clear all the currently stored parameters that have been set
with tt_params.
tt_pre_process¶
This is an overridable method that works in the spirit of cgiapp_prerun. The
method will be called just before a template is processed, and will be passed
the template filename, and a hashref of template parameters. It can be used to
make last minute changes to the template, or the parameters before the
template is processed.
sub tt_pre_process {
my ($self, $file, $vars) = @_;
$vars->{user} = $ENV{REMOTE_USER};
return;
}
If you are using CGI::Application 4.0 or greater, you can also register this as
a callback.
__PACKAGE__->add_callback('tt_pre_process', sub {
my ($self, $file, $vars) = @_;
$vars->{user} = $ENV{REMOTE_USER};
return;
});
tt_post_process¶
This, like it's counterpart cgiapp_postrun, is called right after a template has
been processed. It will be passed a scalar reference to the processed
template.
sub tt_post_process {
my ($self, $htmlref) = shift;
require HTML::Clean;
my $h = HTML::Clean->new($htmlref);
$h->strip;
my $newref = $h->data;
$$htmlref = $$newref;
return;
}
If you are using CGI::Application 4.0 or greater, you can also register this as
a callback (See tt_pre_process for an example of how to use it).
tt_template_name¶
This method will generate a template name for you based on two pieces of
information: the method name of the caller, and the package name of the
caller. It allows you to consistently name your templates based on a directory
hierarchy and naming scheme defined by the structure of the code. This can
simplify development and lead to more consistent, readable code.
If you do not want the template to be named after the method that called
tt_template_name, you can pass in an integer, and the method used to generate
the template name will be that many levels above the caller. It defaults to
zero.
For example:
package My::App::Browser
sub dummy_call {
my $self = shift;
return $self->tt_template_name(1); # parent callers name
}
sub view {
my $self = shift;
my $template;
$template = $self->tt_template_name; # returns 'My/App/Browser/view.tmpl'
$template = $self->dummy_call; # also returns 'My/App/Browser/view.tmpl'
return $self->tt_process($template, { var1 => param1 });
}
To simplify things even more, tt_process automatically calls
$self->tt_template_name for you if you do not pass a template name, so the
above can be reduced to this:
package MyApp::Example
sub view {
my $self = shift;
return $self->tt_process({ var1 => param1 }); # process template 'MyApp/Example/view.tmpl'
}
Since the path is generated based on the name of the module, you could place all
of your templates in the same directory as your perl modules, and then pass
@INC as your INCLUDE_PATH parameter. Whether that is actually a good idea is
left up to the reader.
$self->tt_include_path(\@INC);
tt_include_path¶
This method will allow you to set the include path for the Template Toolkit
object after the object has already been created. Normally you set the
INCLUDE_PATH option when creating the Template Toolkit object, but sometimes
it can be useful to change this value after the object has already been
created. This method will allow you to do that without needing to create an
entirely new Template Toolkit object. This can be especially handy when using
the Singleton support mentioned below, where a Template Toolkit object may
persist across many request. It is important to note that a call to
tt_include_path will change the INCLUDE_PATH for all subsequent calls to this
object, until tt_include_path is called again. So if you change the
INCLUDE_PATH based on the user that is connecting to your site, then make sure
you call tt_include_path on every request.
my $root = '/var/www/';
$self->tt_include_path( [$root.$ENV{SERVER_NAME}, $root.'default'] );
When called with no parameters tt_include_path returns an arrayref containing
the current INCLUDE_PATH.
DEFAULT PARAMETERS¶
By default, the TT plugin will automatically add a parameter 'c' to the template
that will return to your CGI::Application object $self. This allows you to
access any methods in your CGI::Application module that you could normally
call on $self from within your template. This allows for some powerful actions
in your templates. For example, your templates will be able to access query
parameters, or if you use the CGI::Application::Plugin::Session module, you
can access session parameters.
Hello [% c.session.param('username') || 'Anonymous User' %]
<a href="[% c.query.self_url %]">Reload this page</a>
Another useful plugin that can use this feature is the
CGI::Application::Plugin::HTMLPrototype plugin, which gives easy access to the
very powerful prototype.js JavaScript library.
[% c.prototype.define_javascript_functions %]
<a href="#" onclick="javascript:[% c.prototype.visual_effect( 'Appear', 'extra_info' ) %] return false;">Extra Info</a>
<div style="display: none" id="extra_info">Here is some more extra info</div>
With this extra flexibility comes some responsibilty as well. It could lead down
a dangerous path if you start making alterations to your object from within
the template. For example you could call c.header_add to add new outgoing
headers, but that is something that should be left in your code, not in your
template. Try to limit yourself to pulling in information into your templates
(like the session example above does).
EXAMPLE¶
In a CGI::Application module:
package My::App
use CGI::Application::Plugin::TT;
use base qw(CGI::Application);
# configure the template object once during the init stage
sub cgiapp_init {
my $self = shift;
# Configure the template
$self->tt_config(
TEMPLATE_OPTIONS => {
INCLUDE_PATH => '/path/to/template/files',
POST_CHOMP => 1,
FILTERS => {
'currency' => sub { sprintf('$ %0.2f', @_) },
},
},
);
}
sub cgiapp_prerun {
my $self = shift;
# Add the username to all templates if the user is logged in
$self->tt_params(username => $ENV{REMOTE_USER}) if $ENV{REMOTE_USER};
}
sub tt_pre_process {
my $self = shift;
my $template = shift;
my $params = shift;
# could add the username here instead if we want
$params->{username} = $ENV{REMOTE_USER}) if $ENV{REMOTE_USER};
return;
}
sub tt_post_process {
my $self = shift;
my $htmlref = shift;
# clean up the resulting HTML
require HTML::Clean;
my $h = HTML::Clean->new($htmlref);
$h->strip;
my $newref = $h->data;
$$htmlref = $$newref;
return;
}
sub my_runmode {
my $self = shift;
my %params = (
foo => 'bar',
);
# return the template output
return $self->tt_process('my_runmode.tmpl', \%params);
}
sub my_otherrunmode {
my $self = shift;
my %params = (
foo => 'bar',
);
# Since we don't provide the name of the template to tt_process, it
# will be auto-generated by a call to $self->tt_template_name,
# which will result in a filename of 'Example/my_otherrunmode.tmpl'.
return $self->tt_process(\%params);
}
SINGLETON SUPPORT¶
Creating a Template Toolkit object can be an expensive operation if it needs to
be done for every request. This startup cost increases dramatically as the
number of templates you use increases. The reason for this is that when TT
loads and parses a template, it generates actual perlcode to do the rendering
of that template. This means that the rendering of the template is extremely
fast, but the initial parsing of the templates can be inefficient. Even by
using the builting caching mechanism that TT provides only writes the
generated perl code to the filesystem. The next time a TT object is created,
it will need to load these templates from disk, and eval the sourcecode that
they contain.
So to improve the efficiency of Template Toolkit, we should keep the object (and
hence all the compiled templates) in memory across multiple requests. This
means you only get hit with the startup cost the first time the TT object is
created.
All you need to do to use this module as a singleton is to call tt_config as a
class method instead of as an object method. All the same parameters can be
used when calling tt_config as a class method.
When creating the singleton, the Template Toolkit object will be saved in the
namespace of the module that created it. The singleton will also be inherited
by any subclasses of this module. So in effect this is not a traditional
Singleton, since an instance of a Template Toolkit object is only shared by a
module and it's children. This allows you to still have different
configurations for different CGI::Application modules if you require it. If
you want all of your CGI::Application applications to share the same Template
Toolkit object, just create a Base class that calls tt_config to configure the
plugin, and have all of your applications inherit from this Base class.
SINGLETON EXAMPLE¶
package My::App;
use base qw(CGI::Application);
use CGI::Application::Plugin::TT;
My::App->tt_config(
TEMPLATE_OPTIONS => {
POST_CHOMP => 1,
},
);
sub cgiapp_prerun {
my $self = shift;
# Set the INCLUDE_PATH (will change the INCLUDE_PATH for
# all subsequent requests as well, until tt_include_path is called
# again)
my $basedir = '/path/to/template/files/',
$self->tt_include_path( [$basedir.$ENV{SERVER_NAME}, $basedir.'default'] );
}
sub my_runmode {
my $self = shift;
# Will use the same TT object across multiple request
return $self->tt_process({ param1 => 'value1' });
}
package My::App::Subclass;
use base qw(My::App);
sub my_other_runmode {
my $self = shift;
# Uses the TT object from the parent class (My::App)
return $self->tt_process({ param2 => 'value2' });
}
AUTHOR¶
Cees Hek <ceeshek@gmail.com>
BUGS¶
Please report any bugs or feature requests to
"bug-cgi-application-plugin-tt@rt.cpan.org", or through the web
interface at <
http://rt.cpan.org>. I will be notified, and then you'll
automatically be notified of progress on your bug as I make changes.
CONTRIBUTING¶
Patches, questions and feedback are welcome.
SEE ALSO¶
CGI::Application, Template,
perl(1)
LICENSE¶
Copyright (C) 2005 Cees Hek, All Rights Reserved.
This library is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.