How to use PHP instead of Twig for Templates

Even if Symfony2 defaults to Twig for its template engine, you can still use plain PHP code if you want. Both templating engines are supported equally in Symfony2. Symfony2 adds some nice features on top of PHP to make writing templates with PHP more powerful.

Rendering PHP Templates

If you want to use the PHP templating engine, first, make sure to enable it in your application configuration file:

  • YAML
    # app/config/config.yml
framework:
    # ...
    templating:    { engines: ['twig', 'php'] }
  • XML
    <!-- app/config/config.xml -->
<framework:config ... >
    <!-- ... -->
    <framework:templating ... >
        <framework:engine id="twig" />
        <framework:engine id="php" />
    </framework:templating>
</framework:config>
  • PHP
    $container->loadFromExtension('framework', array(
    // ...
    'templating'      => array(
        'engines' => array('twig', 'php'),
    ),
));

You can now render a PHP template instead of a Twig one simply by using the .php extension in the template name instead of .twig. The controller below renders the index.html.php template:

// src/Acme/HelloBundle/Controller/HelloController.php

public function indexAction($name)
{
    return $this->render('AcmeHelloBundle:Hello:index.html.php', array('name' => $name));
}

Decorating Templates

More often than not, templates in a project share common elements, like the well-known header and footer. In Symfony2, we like to think about this problem differently: a template can be decorated by another one.

The index.html.php template is decorated by layout.html.php, thanks to the extend() call:

<!-- src/Acme/HelloBundle/Resources/views/Hello/index.html.php -->
<?php $view->extend('AcmeHelloBundle::layout.html.php') ?>

Hello <?php echo $name ?>!

The AcmeHelloBundle::layout.html.php notation sounds familiar, doesn’t it? It is the same notation used to reference a template. The :: part simply means that the controller element is empty, so the corresponding file is directly stored under views/.

Now, let’s have a look at the layout.html.php file:

<!-- src/Acme/HelloBundle/Resources/views/layout.html.php -->
<?php $view->extend('::base.html.php') ?>

<h1>Hello Application</h1>

<?php $view['slots']->output('_content') ?>

The layout is itself decorated by another one (::base.html.php). Symfony2 supports multiple decoration levels: a layout can itself be decorated by another one. When the bundle part of the template name is empty, views are looked for in the app/Resources/views/ directory. This directory store global views for your entire project:

<!-- app/Resources/views/base.html.php -->
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title><?php $view['slots']->output('title', 'Hello Application') ?></title>
    </head>
    <body>
        <?php $view['slots']->output('_content') ?>
    </body>
</html>

For both layouts, the $view['slots']->output('_content') expression is replaced by the content of the child template, index.html.php and layout.html.php respectively (more on slots in the next section).

As you can see, Symfony2 provides methods on a mysterious $view object. In a template, the $view variable is always available and refers to a special object that provides a bunch of methods that makes the template engine tick.

Working with Slots

A slot is a snippet of code, defined in a template, and reusable in any layout decorating the template. In the index.html.php template, define a title slot:

<!-- src/Acme/HelloBundle/Resources/views/Hello/index.html.php -->
<?php $view->extend('AcmeHelloBundle::layout.html.php') ?>

<?php $view['slots']->set('title', 'Hello World Application') ?>

Hello <?php echo $name ?>!

The base layout already has the code to output the title in the header:

<!-- app/Resources/views/base.html.php -->
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title><?php $view['slots']->output('title', 'Hello Application') ?></title>
</head>

The output() method inserts the content of a slot and optionally takes a default value if the slot is not defined. And _content is just a special slot that contains the rendered child template.

For large slots, there is also an extended syntax:

<?php $view['slots']->start('title') ?>
    Some large amount of HTML
<?php $view['slots']->stop() ?>

Including other Templates

The best way to share a snippet of template code is to define a template that can then be included into other templates.

Create a hello.html.php template:

<!-- src/Acme/HelloBundle/Resources/views/Hello/hello.html.php -->
Hello <?php echo $name ?>!

And change the index.html.php template to include it:

<!-- src/Acme/HelloBundle/Resources/views/Hello/index.html.php -->
<?php $view->extend('AcmeHelloBundle::layout.html.php') ?>

<?php echo $view->render('AcmeHelloBundle:Hello:hello.html.php', array('name' => $name)) ?>

The render() method evaluates and returns the content of another template (this is the exact same method as the one used in the controller).

Embedding other Controllers

And what if you want to embed the result of another controller in a template? That’s very useful when working with Ajax, or when the embedded template needs some variable not available in the main template.

If you create a fancy action, and want to include it into the index.html.php template, simply use the following code:

<!-- src/Acme/HelloBundle/Resources/views/Hello/index.html.php -->
<?php echo $view['actions']->render('AcmeHelloBundle:Hello:fancy', array('name' => $name, 'color' => 'green')) ?>

Here, the AcmeHelloBundle:Hello:fancy string refers to the fancy action of the Hello controller:

// src/Acme/HelloBundle/Controller/HelloController.php

class HelloController extends Controller
{
    public function fancyAction($name, $color)
    {
        // create some object, based on the $color variable
        $object = ...;

        return $this->render('AcmeHelloBundle:Hello:fancy.html.php', array('name' => $name, 'object' => $object));
    }

    // ...
}

But where is the $view['actions'] array element defined? Like $view['slots'], it’s called a template helper, and the next section tells you more about those.

Using Template Helpers

The Symfony2 templating system can be easily extended via helpers. Helpers are PHP objects that provide features useful in a template context. actions and slots are two of the built-in Symfony2 helpers.

Using Assets: images, JavaScripts, and stylesheets

What would the Internet be without images, JavaScripts, and stylesheets? Symfony2 provides the assets tag to deal with them easily:

<link href="<?php echo $view['assets']->getUrl('css/blog.css') ?>" rel="stylesheet" type="text/css" />

<img src="<?php echo $view['assets']->getUrl('images/logo.png') ?>" />

The assets helper’s main purpose is to make your application more portable. Thanks to this helper, you can move the application root directory anywhere under your web root directory without changing anything in your template’s code.

Output Escaping

When using PHP templates, escape variables whenever they are displayed to the user:

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

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

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