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Catalyst::View::TT(3) User Contributed Perl DocumentationCatalyst::View::TT(3)

NAME
       Catalyst::View::TT - Template View Class

SYNOPSIS
       # use the helper	to create your View

	   myapp_create.pl view	Web TT

       # add custom configuration in View/Web.pm

	   __PACKAGE__->config(
	       # any TT	configuration items go here
	       TEMPLATE_EXTENSION => '.tt',
	       CATALYST_VAR => 'c',
	       TIMER	    => 0,
	       ENCODING	    => 'utf-8'
	       # Not set by default
	       PRE_PROCESS	  => 'config/main',
	       WRAPPER		  => 'site/wrapper',
	       render_die => 1,	# Default for new apps,	see render method docs
	       expose_methods => [qw/method_in_view_class/],
	   );

       # add include path configuration	in MyApp.pm

	   __PACKAGE__->config(
	       'View::Web' => {
		   INCLUDE_PATH	=> [
		       __PACKAGE__->path_to( 'root', 'src' ),
		       __PACKAGE__->path_to( 'root', 'lib' ),
		   ],
	       },
	   );

       # render	view from lib/MyApp.pm or
       lib/MyApp::Controller::SomeController.pm

	   sub message : Global	{
	       my ( $self, $c )	= @_;
	       $c->stash->{template} = 'message.tt2';
	       $c->stash->{message}  = 'Hello World!';
	       $c->forward( $c->view('Web') );
	   }

       # access	variables from template

	   The message is: [% message %].

	   # example when CATALYST_VAR is set to 'Catalyst'
	   Context is [% Catalyst %]
	   The base is [% Catalyst.req.base %]
	   The name is [% Catalyst.config.name %]

	   # example when CATALYST_VAR isn't set
	   Context is [% c %]
	   The base is [% base %]
	   The name is [% name %]

DESCRIPTION
       This is the Catalyst view class for the Template	Toolkit.  Your
       application should defined a view class which is	a subclass of this
       module. Throughout this manual it will be assumed that your application
       is named	MyApp and you are creating a TT	view named Web;	these names
       are placeholders	and should always be replaced with whatever name
       you've chosen for your application and your view. The easiest way to
       create a	TT view	class is through the myapp_create.pl script that is
       created along with the application:

	   $ script/myapp_create.pl view Web TT

       This creates a MyApp::View::Web.pm module in the	lib directory (again,
       replacing "MyApp" with the name of your application) which looks
       something like this:

	   package FooBar::View::Web;
	   use Moose;

	   extends 'Catalyst::View::TT';

	   __PACKAGE__->config(DEBUG =>	'all');

       Now you can modify your action handlers in the main application and/or
       controllers to forward to your view class.  You might choose to do this
       in the end() method, for	example, to automatically forward all actions
       to the TT view class.

	   # In	MyApp or MyApp::Controller::SomeController

	   sub end : Private {
	       my( $self, $c ) = @_;
	       $c->forward( $c->view('Web') );
	   }

       But if you are using the	standard auto-generated	end action, you	don't
       even need to do this!

	   # in	MyApp::Controller::Root
	   sub end : ActionClass('RenderView') {} # no need to change this line

	   # in	MyApp.pm
	   __PACKAGE__->config(
	       ...
	       default_view => 'Web',
	   );

       This will Just Work.  And it has	the advantages that:

       o   If you want to use a	different view for a given request, just set
	   << $c->stash->{current_view}	>>.  (See Catalyst's "$c->view"	method
	   for details.

       o   << $c->res->redirect	>> is handled by default.  If you just forward
	   to "View::Web" in your "end"	routine, you could break this by
	   sending additional content.

       See Catalyst::Action::RenderView	for more details.

   CONFIGURATION
       There are a three different ways	to configure your view class.  The
       first way is to call the	"config()" method in the view subclass.	 This
       happens when the	module is first	loaded.

	   package MyApp::View::Web;
	   use Moose;
	   extends 'Catalyst::View::TT';

	   __PACKAGE__->config({
	       PRE_PROCESS  => 'config/main',
	       WRAPPER	    => 'site/wrapper',
	   });

       You may also override the configuration provided	in the view class by
       adding a	'View::Web' section to your application	config.

       This should generally be	used to	inject the include paths into the view
       to avoid	the view trying	to load	the application	to resolve paths.

	   .. inside MyApp.pm ..
	   __PACKAGE__->config(
	       'View::Web' => {
		   INCLUDE_PATH	=> [
		       __PACKAGE__->path_to( 'root', 'templates', 'lib'	),
		       __PACKAGE__->path_to( 'root', 'templates', 'src'	),
		   ],
	       },
	   );

       You can also configure your view	from within your config	file if	you're
       using Catalyst::Plugin::ConfigLoader. This should be reserved for
       deployment-specific concerns. For example:

	   # MyApp_local.conf (Config::General format)

	   <View Web>
	     WRAPPER "custom_wrapper"
	     INCLUDE_PATH __path_to('root/templates/custom_site')__
	     INCLUDE_PATH __path_to('root/templates')__
	   </View>

       might be	used as	part of	a simple way to	deploy different instances of
       the same	application with different themes.

   DYNAMIC INCLUDE_PATH
       Sometimes it is desirable to modify INCLUDE_PATH	for your templates at
       run time.

       Additional paths	can be added to	the start of INCLUDE_PATH via the
       stash as	follows:

	   $c->stash->{additional_template_paths} =
	       [$c->config->{root} . '/test_include_path'];

       If you need to add paths	to the end of INCLUDE_PATH, there is also an
       include_path() accessor available:

	   push( @{ $c->view('Web')->include_path }, qw/path/ );

       Note that if you	use include_path() to add extra	paths to INCLUDE_PATH,
       you MUST	check for duplicate paths. Without such	checking, the above
       code will add "path" to INCLUDE_PATH at every request, causing a	memory
       leak.

       A safer approach	is to use include_path() to overwrite the array	of
       paths rather than adding	to it. This eliminates both the	need to
       perform duplicate checking and the chance of a memory leak:

	   @{ $c->view('Web')->include_path } =	qw/path	another_path/;

       If you are calling "render" directly then you can specify dynamic paths
       by having a "additional_template_paths" key with	a value	of additional
       directories to search. See "CAPTURING TEMPLATE OUTPUT" for an example
       showing this.

   Unicode (pre	Catalyst v5.90080)
       NOTE Starting with Catalyst v5.90080 unicode and	encoding has been
       baked into core,	and the	default	encoding is UTF-8.  The	following
       advice is for older versions of Catalyst.

       Be sure to set "ENCODING	=> 'utf-8'" and	use
       Catalyst::Plugin::Unicode::Encoding if you want to use non-ascii
       characters (encoded as utf-8) in	your templates.	 This is only needed
       if you actually have UTF8 literals in your templates and	the BOM	is not
       properly	set.  Setting encoding here does not magically encode your
       template	output.	 If you	are using this version of Catalyst you need to
       all the Unicode plugin, or upgrade (preferred)

   Unicode (Catalyst v5.90080+)
       This version of Catalyst	will automatically encode your body output to
       UTF8. This means	if your	variables contain multibyte characters you
       don't need top do anything else to get UTF8 output.  However if your
       templates contain UTF8 literals (like, multibyte	characters actually in
       the template text), then	you do need to either set the BOM mark on the
       template	file or	instruct TT to decode the templates at load time via
       the ENCODING configuration setting.  Most of the	time you can just do:

	   MyApp::View::HTML->config(
	       ENCODING	=> 'UTF-8');

       and that	will just take care of everything.  This configuration setting
       will force Template to decode all files correctly, so that when you hit
       the finalize_encoding step we can properly encode the body as UTF8.  If
       you fail	to do this you will get	double encoding	issues in your output
       (but again, only	for the	UTF8 literals in your actual template text.)

       Again, this ENCODING configuration setting only instructs template
       toolkit how (and	if) to decode the contents of your template files when
       reading them from disk.	It has no other	effect.

   RENDERING VIEWS
       The view	plugin renders the template specified in the "template"	item
       in the stash.

	   sub message : Global	{
	       my ( $self, $c )	= @_;
	       $c->stash->{template} = 'message.tt2';
	       $c->forward( $c->view('Web') );
	   }

       If a stash item isn't defined, then it instead uses the stringification
       of the action dispatched	to (as defined by $c->action) in the above
       example,	this would be "message", but because the default is to append
       '.tt', it would load "root/message.tt".

       The items defined in the	stash are passed to the	Template Toolkit for
       use as template variables.

	   sub default : Private {
	       my ( $self, $c )	= @_;
	       $c->stash->{template} = 'message.tt2';
	       $c->stash->{message}  = 'Hello World!';
	       $c->forward( $c->view('Web') );
	   }

       A number	of other template variables are	also added:

	   c	  A reference to the context object, $c
	   base	  The URL base,	from $c->req->base()
	   name	  The application name,	from $c->config->{ name	}

       These can be accessed from the template in the usual way:

       <message.tt2>:

	   The message is: [% message %]
	   The base is [% base %]
	   The name is [% name %]

       The output generated by the template is stored in "$c->response->body".

   CAPTURING TEMPLATE OUTPUT
       If you wish to use the output of	a template for some other purpose than
       displaying in the response, e.g.	for sending an email, this is possible
       using other views, such as Catalyst::View::Email::Template.

   TEMPLATE PROFILING
       See ""TIMER"" property of the "config" method.

METHODS
   new
       The constructor for the TT view.	Sets up	the template provider, and
       reads the application config.

   process($c)
       Renders the template specified in "$c->stash->{template}" or
       "$c->action" (the private name of the matched action).  Calls render to
       perform actual rendering. Output	is stored in "$c->response->body".

       It is possible to forward to the	process	method of a TT view from
       inside Catalyst like this:

	   $c->forward('View::Web');

       N.B. This is usually done automatically by
       Catalyst::Action::RenderView.

   render($c, $template, \%args)
       Renders the given template and returns output. Throws a
       Template::Exception object upon error.

       The template variables are set to %$args	if $args is a hashref, or
       "$c->stash" otherwise. In either	case the variables are augmented with
       "base" set to "$c->req->base", "c" to $c, and "name" to
       "$c->config->{name}". Alternately, the "CATALYST_VAR" configuration
       item can	be defined to specify the name of a template variable through
       which the context reference ($c)	can be accessed. In this case, the
       "c", "base", and	"name" variables are omitted.

       $template can be	anything that Template::process	understands how	to
       process,	including the name of a	template file or a reference to	a test
       string.	See Template::process for a full list of supported formats.

       To use the render method	outside	of your	Catalyst app, just pass	a
       undef context.  This can	be useful for tests, for instance.

       It is possible to forward to the	render method of a TT view from	inside
       Catalyst	to render page fragments like this:

	   my $fragment	= $c->forward("View::Web", "render", $template_name, $c->stash->{fragment_data});

       Backwards compatibility note

       The render method used to just return the Template::Exception object,
       rather than just	throwing it. This is now deprecated and	instead	the
       render method will throw	an exception for new applications.

       This behaviour can be activated (and is activated in the	default
       skeleton	configuration) by using	"render_die => 1". If you rely on the
       legacy behaviour	then a warning will be issued.

       To silence this warning,	set "render_die	=> 0", but it is recommended
       you adjust your code so that it works with "render_die => 1".

       In a future release, "render_die	=> 1" will become the default if
       unspecified.

   template_vars
       Returns a list of keys/values to	be used	as the catalyst	variables in
       the template.

   config
       This method allows your view subclass to	pass additional	settings to
       the TT configuration hash, or to	set the	options	as below:

   paths
       The list	of paths TT will look for templates in.

   expose_methods
       The list	of methods in your View	class which should be made available
       to the templates.

       For example:

	 expose_methods	=> [qw/uri_for_css/],

	 ...

	 sub uri_for_css {
	   my ($self, $c, $filename) = @_;

	   # additional	complexity like	checking file exists here

	   return $c->uri_for('/static/css/' . $filename);
	 }

       Then in the template:

	 [% uri_for_css('home.css') %]

   content_type
       This lets you override the default content type for the response.  If
       you do not set this and if you do not set the content type in your
       controllers, the	default	is "text/html; charset=utf-8".

       Use this	if you are creating alternative	view responses,	such as	text
       or JSON and want	a global setting.

       Any content type	set in your controllers	before calling this view are
       respected and have priority.

   "CATALYST_VAR"
       Allows you to change the	name of	the Catalyst context object. If	set,
       it will also remove the base and	name aliases, so you will have access
       them through <context>.

       For example, if CATALYST_VAR has	been set to "Catalyst",	a template
       might contain:

	   The base is [% Catalyst.req.base %]
	   The name is [% Catalyst.config.name %]

   "TIMER"
       If you have configured Catalyst for debug output, and turned on the
       TIMER setting, "Catalyst::View::TT" will	enable profiling of template
       processing (using Template::Timer). This	will embed HTML	comments in
       the output from your templates, such as:

	   <!--	TIMER START: process mainmenu/mainmenu.ttml -->
	   <!--	TIMER START: include mainmenu/cssindex.tt -->
	   <!--	TIMER START: process mainmenu/cssindex.tt -->
	   <!--	TIMER END: process mainmenu/cssindex.tt	(0.017279 seconds) -->
	   <!--	TIMER END: include mainmenu/cssindex.tt	(0.017401 seconds) -->

	   ....

	   <!--	TIMER END: process mainmenu/footer.tt (0.003016	seconds) -->

   "TEMPLATE_EXTENSION"
       a suffix	to add when looking for	templates bases	on the "match" method
       in Catalyst::Request.

       For example:

	 package MyApp::Controller::Test;
	 sub test : Local { .. }

       Would by	default	look for a template in <root>/test/test. If you	set
       TEMPLATE_EXTENSION to '.tt', it will look for <root>/test/test.tt.

   "PROVIDERS"
       Allows you to specify the template providers that TT will use.

	   MyApp->config(
	       name	=> 'MyApp',
	       root	=> MyApp->path_to('root'),
	       'View::Web' => {
		   PROVIDERS =>	[
		       {
			   name	   => 'DBI',
			   args	   => {
			       DBI_DSN => 'dbi:DB2:books',
			       DBI_USER=> 'foo'
			   }
		       }, {
			   name	   => '_file_',
			   args	   => {}
		       }
		   ]
	       },
	   );

       The 'name' key should correspond	to the class name of the provider you
       want to use.  The _file_	name is	a special case that represents the
       default TT file-based provider.	By default the name is will be
       prefixed	with 'Template::Provider::'.  You can fully qualify the	name
       by using	a unary	plus:

	   name	=> '+MyApp::Provider::Foo'

       You can also specify the	'copy_config' key as an	arrayref, to copy
       those keys from the general config, into	the config for the provider:

	   DEFAULT_ENCODING    => 'utf-8',
	   PROVIDERS =>	[
	       {
		   name	   => 'Encoding',
		   copy_config => [qw(DEFAULT_ENCODING INCLUDE_PATH)]
	       }
	   ]

       This can	prove useful when you want to use the
       additional_template_paths hack in your own provider, or if you need to
       use Template::Provider::Encoding

   "CLASS"
       Allows you to specify a custom class to use as the template class
       instead of Template.

	   package MyApp::View::Web;
	   use Moose;
	   extends 'Catalyst::View::TT';

	   use Template::AutoFilter;

	   __PACKAGE__->config({
	       CLASS =>	'Template::AutoFilter',
	   });

       This is useful if you want to use your own subclasses of	Template, so
       you can,	for example, prevent XSS by automatically filtering all	output
       through "| html".

   HELPERS
       The Catalyst::Helper::View::TT and Catalyst::Helper::View::TTSite
       helper modules are provided to create your view module.	There are
       invoked by the myapp_create.pl script:

	   $ script/myapp_create.pl view Web TT

	   $ script/myapp_create.pl view Web TTSite

       The Catalyst::Helper::View::TT module creates a basic TT	view module.
       The Catalyst::Helper::View::TTSite module goes a	little further.	 It
       also creates a default set of templates to get you started.  It also
       configures the view module to locate the	templates automatically.

NOTES
       If you are using	the CGI	module inside your templates, you will
       experience that the Catalyst server appears to hang while rendering the
       web page. This is due to	the debug mode of CGI (which is	waiting	for
       input in	the terminal window). Turning off the debug mode using the
       "-no_debug" option solves the problem, eg.:

	   [% USE CGI('-no_debug') %]

SEE ALSO
       Catalyst, Catalyst::Helper::View::TT, Catalyst::Helper::View::TTSite,
       Template::Manual

AUTHORS
       Sebastian Riedel, "sri@cpan.org"

       Marcus Ramberg, "mramberg@cpan.org"

       Jesse Sheidlower, "jester@panix.com"

       Andy Wardley, "abw@cpan.org"

       Luke Saunders, "luke.saunders@gmail.com"

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

perl v5.32.1			  2020-07-20		 Catalyst::View::TT(3)

NAME | SYNOPSIS | DESCRIPTION | METHODS | NOTES | SEE ALSO | AUTHORS | COPYRIGHT

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