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.. index::
   single: Templating
   single: Components; Templating

The Templating Component

The Templating Component provides all the tools needed to build any kind of template system.

It provides an infrastructure to load template files and optionally monitor them for changes. It also provides a concrete template engine implementation using PHP with additional tools for escaping and separating templates into blocks and layouts.

Installation

You can install the component in 2 different ways:

Usage

The :class:`Symfony\\Component\\Templating\\PhpEngine` class is the entry point of the component. It needs a template name parser (:class:`Symfony\\Component\\Templating\\TemplateNameParserInterface`) to convert a template name to a template reference (:class:`Symfony\\Component\\Templating\\TemplateReferenceInterface`). It also needs a template loader (:class:`Symfony\\Component\\Templating\\Loader\\LoaderInterface`) which uses the template reference to actually find and load the template:

use Symfony\Component\Templating\PhpEngine;
use Symfony\Component\Templating\TemplateNameParser;
use Symfony\Component\Templating\Loader\FilesystemLoader;

$loader = new FilesystemLoader(__DIR__.'/views/%name%');

$templating = new PhpEngine(new TemplateNameParser(), $loader);

echo $templating->render('hello.php', array('firstname' => 'Fabien'));

<!-- views/hello.php -->
Hello, <?php echo $firstname ?>!

The :method:`Symfony\\Component\\Templating\\PhpEngine::render` method parses the views/hello.php file and returns the output text. The second argument of render is an array of variables to use in the template. In this example, the result will be Hello, Fabien!.

The $view variable

In all templates parsed by the PhpEngine, you get access to a mysterious variable called $view. That variable holds the current PhpEngine instance. That means you get access to a bunch of methods that make your life easier.

Including Templates

The best way to share a snippet of template code is to create a template that can then be included by other templates. As the $view variable is an instance of PhpEngine, you can use the render method (which was used to render the template originally) inside the template to render another template:

<?php $names = array('Fabien', ...) ?>
<?php foreach ($names as $name) : ?>
    <?php echo $view->render('hello.php', array('firstname' => $name)) ?>
<?php endforeach ?>

Output Escaping

When you render variables, you should probably escape them so that HTML or JavaScript code isn't written out to your page. This will prevent things like XSS attacks. To do this, use the :method:`Symfony\\Component\\Templating\\PhpEngine::escape` method:

<?php echo $view->escape($firstname) ?>

By default, the escape() method assumes that the variable is outputted within an HTML context. The second argument lets you change the context. For example, to output something inside JavaScript, use the js context:

<?php echo $view->escape($var, 'js') ?>

The component comes with an HTML and JS escaper. You can register your own escaper using the :method:`Symfony\\Component\\Templating\\PhpEngine::setEscaper` method:

$templating->setEscaper('css', function ($value) {
    // ... all CSS escaping

    return $escapedValue;
});

Helpers

The Templating component can be easily extended via helpers. The component has 2 built-in helpers:

Before you can use these helpers, you need to register them using :method:`Symfony\\Component\\Templating\\PhpEngine::set`:

use Symfony\Component\Templating\Helper\AssetsHelper;
// ...

$templating->set(new AssetsHelper());

Custom Helpers

You can create your own helpers by creating a class which implements :class:`Symfony\\Component\\Templating\\Helper\\HelperInterface`. However, most of the time you'll extend :class:`Symfony\\Component\\Templating\\Helper\\Helper`.

The Helper has one required method: :method:`Symfony\\Component\\Templating\\Helper\\HelperInterface::getName`. This is the name that is used to get the helper from the $view object.