|
| 1 | +.. index:: |
| 2 | + single: Twig extensions |
| 3 | + |
| 4 | +How to write a custom Twig extension |
| 5 | +============================================ |
| 6 | + |
| 7 | +The main motivation for writing an extension is to move often used code into a reusable class like adding support for internationalization. |
| 8 | +An extension can define tags, filters, tests, operators, global variables, functions, and node visitors. |
| 9 | + |
| 10 | +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. |
| 11 | + |
| 12 | +.. tip:: |
| 13 | + |
| 14 | + Before writing your own extensions, have a look at the `Twig official extension repository`_. |
| 15 | + |
| 16 | +Create the extension class |
| 17 | +-------------------------- |
| 18 | + |
| 19 | +To get your custom functionality you must first create a Twig Extension class. |
| 20 | +As an example we will create a price filter to format a given number into price. |
| 21 | + |
| 22 | + .. code-block:: php |
| 23 | +
|
| 24 | + <?php |
| 25 | + |
| 26 | + // src/Acme/DemoBundle/Twig/AcmeExtension.php |
| 27 | +
|
| 28 | + namespace Acme\DemoBundle\Twig; |
| 29 | +
|
| 30 | + use Twig_Extension; |
| 31 | + use Twig_Filter_Method; |
| 32 | + use Twig_Function_Method; |
| 33 | +
|
| 34 | + class AcmeExtension extends Twig_Extension |
| 35 | + { |
| 36 | + public function getFilters() |
| 37 | + { |
| 38 | + return array( |
| 39 | + 'price' => new Twig_Filter_Method($this, 'priceFilter'), |
| 40 | + ); |
| 41 | + } |
| 42 | + |
| 43 | + public function priceFilter($number, $decimals = 0, $decPoint = '.', $thousandsSep = ',') |
| 44 | + { |
| 45 | + $price = number_format($number, $decimals, $decPoint, $thousandsSep); |
| 46 | + $price = '$' . $price; |
| 47 | +
|
| 48 | + return $price; |
| 49 | + } |
| 50 | +
|
| 51 | + public function getName() |
| 52 | + { |
| 53 | + return 'acme_extension'; |
| 54 | + } |
| 55 | + } |
| 56 | + |
| 57 | +Register extension as a service |
| 58 | +------------------------------- |
| 59 | + |
| 60 | +Now you must let Service Container know about your newly created Twig Extension: |
| 61 | + |
| 62 | +.. configuration-block:: |
| 63 | + |
| 64 | + .. code-block:: xml |
| 65 | + |
| 66 | + <!-- src/Acme/DemoBundle/Resources/config/services.xml --> |
| 67 | + <services> |
| 68 | + <service id="acme.twig.acme_extension" class="Acme\DemoBundle\Twig\AcmeExtension"> |
| 69 | + <tag name="twig.extension" /> |
| 70 | + </service> |
| 71 | + </services> |
| 72 | +
|
| 73 | + .. code-block:: yaml |
| 74 | + |
| 75 | + # src/Acme/DemoBundle/Resources/config/services.yml |
| 76 | + services: |
| 77 | + acme.twig.acme_extension: |
| 78 | + class: Acme\DemoBundle\Twig\AcmeExtension |
| 79 | + tags: |
| 80 | + - { name: twig.extension } |
| 81 | +
|
| 82 | + .. code-block:: php |
| 83 | +
|
| 84 | + // src/Acme/DemoBundle/Resources/config/services.php |
| 85 | + use Symfony\Component\DependencyInjection\Definition; |
| 86 | +
|
| 87 | + $acmeDefinition = new Definition('\Acme\DemoBundle\Twig\AcmeExtension'); |
| 88 | + $acmeDefinition->addTag('twig.extension'); |
| 89 | + $container->setDefinition('acme.twig.acme_extension', $acmeDefinition); |
| 90 | + |
| 91 | + |
| 92 | +Using the custom extension |
| 93 | +--------------------------- |
| 94 | + |
| 95 | +Using your newly created Twig Extension is no different than any other: |
| 96 | + |
| 97 | +.. code-block:: html+jinja |
| 98 | + |
| 99 | + {# outputs $5,500.00 #} |
| 100 | + {{ '5500' | price }} |
| 101 | + |
| 102 | +.. _`Twig official extension repository`: http://github.com/fabpot/Twig-extensions |
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