Symfony
a SensioLabs product
DOWNLOAD NOW

Table of Contents

Creative Commons License
This work is licensed under a
Creative Commons
Attribution-Share Alike 3.0
Unported License.

Master Symfony2 fundamentals

Be trained by SensioLabs experts (2 to 6 day sessions -- French or English).
trainings.sensiolabs.com

Symfony hosting done right

ServerGrove, outstanding support at the right price for your Symfony hosting needs.
servergrove.com

Discover the SensioLabs Support

Access to the SensioLabs Competency Center for an exclusive and tailor-made support on Symfony
sensiolabs.com
Home » Documentation » The Cookbook » Templating » How to write a custom Twig Extension
2.0 version

How to write a custom Twig Extension

Caution: You are browsing the documentation for Symfony version 2.0 which is not maintained anymore. If some of your projects are still using this version, consider upgrading.

How to write a custom Twig Extension

The main motivation for writing an extension is to move often used code into a reusable class like adding support for internationalization. An extension can define tags, filters, tests, operators, global variables, functions, and node visitors.

Creating an extension also makes for a better separation of code that is executed at compilation time and code needed at runtime. As such, it makes your code faster.

Tip

Before writing your own extensions, have a look at the Twig official extension repository.

Create the Extension Class

To get your custom functionality you must first create a Twig Extension class. As an example you'll create a price filter to format a given number into price:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
// src/Acme/DemoBundle/Twig/AcmeExtension.php
namespace Acme\DemoBundle\Twig;

class AcmeExtension extends \Twig_Extension
{
    public function getFilters()
    {
        return array(
            'price' => new \Twig_Filter_Method($this, 'priceFilter'),
        );
    }

    public function priceFilter($number, $decimals = 0, $decPoint = '.', $thousandsSep = ',')
    {
        $price = number_format($number, $decimals, $decPoint, $thousandsSep);
        $price = '$' . $price;

        return $price;
    }

    public function getName()
    {
        return 'acme_extension';
    }
}

Tip

Along with custom filters, you can also add custom functions and register global variables.

Register an Extension as a Service

Now you must let the Service Container know about your newly created Twig Extension:

  • YAML
    1
2
3
4
5
6
    # src/Acme/DemoBundle/Resources/config/services.yml
services:
    acme.twig.acme_extension:
        class: Acme\DemoBundle\Twig\AcmeExtension
        tags:
            - { name: twig.extension }
  • XML
    1
2
3
4
5
6
    <!-- src/Acme/DemoBundle/Resources/config/services.xml -->
<services>
    <service id="acme.twig.acme_extension" class="Acme\DemoBundle\Twig\AcmeExtension">
        <tag name="twig.extension" />
    </service>
</services>
  • PHP
    1
2
3
4
5
6
    // src/Acme/DemoBundle/Resources/config/services.php
use Symfony\Component\DependencyInjection\Definition;

$acmeDefinition = new Definition('\Acme\DemoBundle\Twig\AcmeExtension');
$acmeDefinition->addTag('twig.extension');
$container->setDefinition('acme.twig.acme_extension', $acmeDefinition);

Note

Keep in mind that Twig Extensions are not lazily loaded. This means that there's a higher chance that you'll get a CircularReferenceException or a ScopeWideningInjectionException if any services (or your Twig Extension in this case) are dependent on the request service. For more information take a look at How to work with Scopes.

Using the custom Extension

Using your newly created Twig Extension is no different than any other:

1
2
{# outputs $5,500.00 #}
{{ '5500'|price }}

Passing other arguments to your filter:

1
2
{# outputs $5500,2516 #}
{{ '5500.25155'|price(4, ',', '') }}

Learning further

For a more in-depth look into Twig Extensions, please take a look at the Twig extensions documentation.

« How to use PHP instead of Twig for Templates | How to render a Template without a custom Controller »

NEWS FROM THE BLOG

Visit Symfony's blog

IN THE NEWS

Announcing the next Symfony Live Conference 2013 in Portland

UPCOMING TRAINING SESSIONS

View all sessions

sf - Symfony is a trademark of Fabien Potencier. All rights reserved.

What is Symfony?

Get Started

Learn Symfony

Marketplace

Community

Services

Blog

About