Marcus Ramberg > Catalyst-View-TT-0.30 > Catalyst::View::TT

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Module Version: 0.30   Source   Latest Release: Catalyst-View-TT-0.41

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') );
    }

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

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.

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.

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.

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