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serializer.rst

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.. index::
   single: Serializer

How to Use the Serializer

Serializing and deserializing to and from objects and different formats (e.g. JSON or XML) is a very complex topic. Symfony comes with a :doc:`Serializer Component </components/serializer>`, which gives you some tools that you can leverage for your solution.

In fact, before you start, get familiar with the serializer, normalizers and encoders by reading the :doc:`Serializer Component </components/serializer>`.

Activating the Serializer

.. versionadded:: 2.3
    The Serializer has always existed in Symfony, but prior to Symfony 2.3,
    you needed to build the ``serializer`` service yourself.

The serializer service is not available by default. To turn it on, activate it in your configuration:

.. configuration-block::

    .. code-block:: yaml

        # app/config/config.yml
        framework:
            # ...
            serializer: { enable_annotations: true }
            # Alternatively, if you don't want to use annotations
            #serializer: { enabled: true }

    .. code-block:: xml

        <!-- app/config/config.xml -->
        <?xml version="1.0" encoding="UTF-8"?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                http://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                http://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <!-- ... -->
                <framework:serializer enable-annotations="true" />
                <!--
                Alternatively, if you don't want to use annotations
                <framework:serializer enabled="true" />
                -->
            </framework:config>
        </container>

    .. code-block:: php

        // app/config/config.php
        $container->loadFromExtension('framework', array(
            // ...
            'serializer' => array(
                'enable_annotations' => true,
                // Alternatively, if you don't want to use annotations
                //'enabled' => true,
            ),
        ));

Using the Serializer Service

Once enabled, the serializer service can be injected in any service where you need it or it can be used in a controller like the following:

// src/AppBundle/Controller/DefaultController.php
namespace AppBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;

class DefaultController extends Controller
{
    public function indexAction()
    {
        $serializer = $this->get('serializer');

        // ...
    }
}

Adding Normalizers and Encoders

.. versionadded:: 2.7
    The :class:`Symfony\\Component\\Serializer\\Normalizer\\ObjectNormalizer`
    is enabled by default in Symfony 2.7. In prior versions, you needed to load
    your own normalizer.

Once enabled, the serializer service will be available in the container and will be loaded with two :ref:`encoders <component-serializer-encoders>` (:class:`Symfony\\Component\\Serializer\\Encoder\\JsonEncoder` and :class:`Symfony\\Component\\Serializer\\Encoder\\XmlEncoder`) and the :ref:`ObjectNormalizer normalizer <component-serializer-normalizers>`.

You can load normalizers and/or encoders by tagging them as :ref:`serializer.normalizer <reference-dic-tags-serializer-normalizer>` and :ref:`serializer.encoder <reference-dic-tags-serializer-encoder>`. It's also possible to set the priority of the tag in order to decide the matching order.

Here is an example on how to load the :class:`Symfony\\Component\\Serializer\\Normalizer\\GetSetMethodNormalizer`:

.. configuration-block::

    .. code-block:: yaml

        # app/config/services.yml
        services:
            get_set_method_normalizer:
                class: Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer
                public: false
                tags:
                    - { name: serializer.normalizer }

    .. code-block:: xml

        <!-- app/config/services.xml -->
        <?xml version="1.0" encoding="UTF-8"?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                http://symfony.com/schema/dic/services/services-1.0.xsd">

            <services>
                <service id="get_set_method_normalizer" class="Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer" public="false">
                    <tag name="serializer.normalizer" />
                </service>
            </services>
        </container>

    .. code-block:: php

        // app/config/services.php
        use Symfony\Component\Serializer\Normalizer\GetSetMethodNormalizer;

        $container->register('get_set_method_normalizer', GetSetMethodNormalizer::class)
            ->setPublic(false)
            ->addTag('serializer.normalizer')
        ;

Using Serialization Groups Annotations

.. versionadded:: 2.7
    Support for serialization groups was introduced in Symfony 2.7.

Enable :ref:`serialization groups annotation <component-serializer-attributes-groups>` with the following configuration:

.. configuration-block::

    .. code-block:: yaml

        # app/config/config.yml
        framework:
            # ...
            serializer:
                enable_annotations: true

    .. code-block:: xml

        <!-- app/config/config.xml -->
        <?xml version="1.0" encoding="UTF-8"?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                http://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                http://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <!-- ... -->
                <framework:serializer enable-annotations="true" />
            </framework:config>
        </container>

    .. code-block:: php

        // app/config/config.php
        $container->loadFromExtension('framework', array(
            // ...
            'serializer' => array(
                'enable_annotations' => true,
            ),
        ));

Next, add the :ref:`@Groups annotations <component-serializer-attributes-groups-annotations>` to your class and choose which groups to use when serializing:

$serializer = $this->get('serializer');
$json = $serializer->serialize(
    $someObject,
    'json', array('groups' => array('group1'))
);

In addition to the @Groups annotation, the Serializer component also supports Yaml or XML files. These files are automatically loaded when being stored in one of the following locations:

  • The serialization.yml or serialization.xml file in the Resources/config/ directory of a bundle;
  • All *.yml and *.xml files in the Resources/config/serialization/ directory of a bundle.

Enabling the Metadata Cache

.. versionadded:: 2.7
    Serializer metadata and the ability to cache them were introduced in
    Symfony 2.7.

Metadata used by the Serializer component such as groups can be cached to enhance application performance. Any service implementing the Doctrine\Common\Cache\Cache interface can be used.

A service leveraging APCu (and APC for PHP < 5.5) is built-in.

.. configuration-block::

    .. code-block:: yaml

        # app/config/config_prod.yml
        framework:
            # ...
            serializer:
                cache: serializer.mapping.cache.apc

    .. code-block:: xml

        <!-- app/config/config_prod.xml -->
        <?xml version="1.0" encoding="UTF-8"?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                http://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                http://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <!-- ... -->
                <framework:serializer cache="serializer.mapping.cache.apc" />
            </framework:config>
        </container>

    .. code-block:: php

        // app/config/config_prod.php
        $container->loadFromExtension('framework', array(
            // ...
            'serializer' => array(
                'cache' => 'serializer.mapping.cache.apc',
            ),
        ));

Going Further with the Serializer

ApiPlatform provides an API system supporting JSON-LD and Hydra Core Vocabulary hypermedia formats. It is built on top of the Symfony Framework and its Serializer component. It provides custom normalizers and a custom encoder, custom metadata and a caching system.

If you want to leverage the full power of the Symfony Serializer component, take a look at how this bundle works.

.. toctree::
    :maxdepth: 1
    :glob:

    serializer/*