---
name: "Dancer::Template::Abstract"
section: "3pm"
platform: "linux"
package: "libdancer-perl"
version: "1.3521+dfsg-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Dancer::Template::Abstract"
---

# Dancer::Template::Abstract(3pm)

abstract class for Dancer's template engines

## NAME

Dancer::Template::Abstract - abstract class for Dancer's template engines

## VERSION

version 1.3521

## DESCRIPTION

This class is provided as a base class for each template engine. Any template engine must inherit from it and provide a set of methods described below.

## TEMPLATE TOKENS

By default Dancer injects some tokens (or variables) to templates. The available tokens are:

- "perl\_version"

  The current running Perl version.

- "dancer\_version"

  The current running Dancer version.

- "settings"

  Hash to access current application settings.

- "request"

  Hash to access your current request.

- "params"

  Hash to access your request parameters.

- "vars"

  Hash to access your defined variables (using `"vars"`).

- "session"

  Hash to access your session (if you have session enabled)

## INTERFACE

- **init()**

  The template engine can overload this method if some initialization stuff has to be done before the template engine is used.

  The base class provides a plain **init()** method that only returns true.

- **default\_tmpl\_ext()**

  Template class that inherits this class should override this method to return a default template extension, example: for Template::Toolkit it returns "tt" and for HTML::Mason it returns "mason". So when you call `"template 'index';"` in your dispatch code, Dancer will look for a file 'index.tt' or 'index.mason' based on the template you use.

  Note 1: when returning the extension string, please do not add a dot in front of the extension as Dancer will do that.

  Note 2: for backwards compatibility abstract class returns "tt" instead of throwing an exception 'method not implemented'.

  User would be able to change the default extension using the `"<extension"`\> configuration variable on the template configuration. For example, for the default (`"Simple"`) engine:

  ```
       template: "simple"
       engines:
         simple:
           extension: 'tmpl'
  ```

- **view($view)**

  The default behavior of this method is to return the path of the given view, appending the default template extension (either the value of the `"extension"` setting in the configuration, or the value returned by `"default_tmpl_ext"`) if it is not present in the view name given and no layout template with that exact name existed.  (In other words, given a layout name `"main"`, if `"main"` exists in the layouts dir, it will be used; if not, `"main.tmpl"` (where `"tmpl"` is the value of the `"extension"` setting, or the value returned by `"default_tmpl_ext"`) will be looked for.)

- **view\_exists($view\_path)**

  By default, Dancer::Template::Abstract checks to see if it can find the view file calling `"view_exists($path_to_file)"`. If not, it will generate a nice error message for the user.

  If you are using extending Dancer::Template::Abstract to use a template system with multiple document roots (like Text::XSlate or Template), you can override this method to always return true, and therefore skip this check.

- **layout($layout, $tokens, $content)**

  The default behavior of this method is to merge a content with a layout.  The layout file is looked for with similar logic as per `"view"` - an exact match first, then attempting to append the default template extension, if the view name given did not already end with it.

- **render($self, $template, $tokens)**

  This method must be implemented by the template engine. Given a template and a set of tokens, it returns a processed string.

  If `$template` is a reference, it's assumed to be a reference to a string that contains the template itself. If it's not a reference, it's assumed to be the path to template file, as a string. The render method will then have to open it and read its content (Dancer::FileUtils::read\_file\_content does that job).

  This method's return value must be a string which is the result of the interpolation of `$tokens` in `$template`.

  If an error occurs, the method should trigger an exception with `"die()"`.

  Examples :

  ```
      # with a template as a file
      $content = $engine->render('/my/template.txt', { var => 42 };
      # with a template as a scalar
      my $template = "here is <% var %>";
      $content = $engine->render(\$template, { var => 42 });
  ```

## AUTHOR

This module has been written by Alexis Sukrieh, see Dancer for details.

## AUTHOR

Dancer Core Developers

## COPYRIGHT AND LICENSE

This software is copyright (c) 2010 by Alexis Sukrieh.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.