NAME
Catalyst::View::TT - Template View Class
SYNOPSIS
# use the helper to create your View
myapp_create.pl view TT TT
# configure in lib/MyApp.pm (Could be set from configfile instead)
MyApp->config(
name => 'MyApp',
root => MyApp->path_to('root'),
'View::TT' => {
# any TT configurations items go here
INCLUDE_PATH => [
MyApp->path_to( 'root', 'src' ),
MyApp->path_to( 'root', 'lib' ),
],
TEMPLATE_EXTENSION => '.tt',
CATALYST_VAR => 'c',
TIMER => 0,
# Not set by default
PRE_PROCESS => 'config/main',
WRAPPER => 'site/wrapper',
},
);
# 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('TT') );
}
# 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. The easiest way to achieve this is using the myapp_create.pl
script (where myapp should be replaced with whatever your application is
called). This script is created as part of the Catalyst setup.
$ script/myapp_create.pl view TT TT
This creates a MyApp::View::TT.pm module in the lib directory (again,
replacing "MyApp" with the name of your application) which looks
something like this:
package FooBar::View::TT;
use strict;
use warnings;
use base '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('TT') );
}
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 => 'TT',
);
This will Just Work. And it has the advantages that:
* 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.
* << $c->res->redirect >> is handled by default. If you just forward
to "View::TT" in your "end" routine, you could break this by sending
additional content.
See Catalyst::Action::RenderView for more details.
CONFIGURATION
There are a three different ways to configure your view class. The first
way is to call the "config()" method in the view subclass. This happens
when the module is first loaded.
package MyApp::View::TT;
use strict;
use base 'Catalyst::View::TT';
MyApp::View::TT->config({
INCLUDE_PATH => [
MyApp->path_to( 'root', 'templates', 'lib' ),
MyApp->path_to( 'root', 'templates', 'src' ),
],
PRE_PROCESS => 'config/main',
WRAPPER => 'site/wrapper',
});
The second way is to define a "new()" method in your view subclass. This
performs the configuration when the view object is created, shortly
after being loaded. Remember to delegate to the base class "new()"
method (via "$self->next::method()" in the example below) after
performing any configuration.
sub new {
my $self = shift;
$self->config({
INCLUDE_PATH => [
MyApp->path_to( 'root', 'templates', 'lib' ),
MyApp->path_to( 'root', 'templates', 'src' ),
],
PRE_PROCESS => 'config/main',
WRAPPER => 'site/wrapper',
});
return $self->next::method(@_);
}
The final, and perhaps most direct way, is to define a class item in
your main application configuration, again by calling the ubiquitous
"config()" method. The items in the class hash are added to those
already defined by the above two methods. This happens in the base class
new() method (which is one reason why you must remember to call it via
"MRO::Compat" if you redefine the "new()" method in a subclass).
package MyApp;
use strict;
use Catalyst;
MyApp->config({
name => 'MyApp',
root => MyApp->path_to('root'),
'View::TT' => {
INCLUDE_PATH => [
MyApp->path_to( 'root', 'templates', 'lib' ),
MyApp->path_to( 'root', 'templates', 'src' ),
],
PRE_PROCESS => 'config/main',
WRAPPER => 'site/wrapper',
},
});
Note that any configuration items defined by one of the earlier methods
will be overwritten by items of the same name provided by the latter
methods.
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('TT')->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('TT')->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 additonal
directories to search. See "CAPTURING TEMPLATE OUTPUT" for an example
showing this.
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('TT') );
}
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('TT') );
}
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 Catalyst::Plugin::Email and the render method:
sub send_email : Local {
my ($self, $c) = @_;
$c->email(
header => [
To => 'me@localhost',
Subject => 'A TT Email',
],
body => $c->view('TT')->render($c, 'email.tt', {
additional_template_paths => [ $c->config->{root} . '/email_templates'],
email_tmpl_param1 => 'foo'
}
),
);
# Redirect or display a message
}
TEMPLATE PROFILING
See "TIMER" property of the config method.
METHODS
new
The constructor for the TT view. Sets up the template provider, and
reads the application config.
process($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:
$c->forward('View::TT');
N.B. This is usually done automatically by Catalyst::Action::RenderView.
render($c, $template, \%args)
Renders the given template and returns output, or a Template::Exception
object upon error.
The template variables are set to %$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::TT", "render", $template_name, $c->stash->{fragment_data});
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.
"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:
MyApp->config({
name => 'MyApp',
root => MyApp->path_to('root'),
'View::TT' => {
CATALYST_VAR => 'Catalyst',
},
});
message.tt2:
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 sufix 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::TT' => {
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
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 TT TT
$ script/myapp_create.pl view TT 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"
COPYRIGHT
This program is free software. You can redistribute it and/or modify it
under the same terms as Perl itself.