Performance

To figure which normalizer (or denormalizer) must be used to handle an object,

the :class:`Symfony\\Component\\Serializer\\Serializer` class will call the

:method:`Symfony\Component\Serializer\Normalizer\NormalizerInterface::supportsNormalization`

(or :method:`Symfony\Component\Serializer\Normalizer\DenormalizerInterface::supportsDenormalization`)

of all registered normalizers (or denormalizers) in a loop.

The result of these methods can vary depending of the value of the object to serialize, of the format to

use, and of the context. Consequently, **it is not cached** by default.

Because they are called recursively, these methods are usually a huge performance bottleneck. Moreover, most

normalizers (and denormalizers) always return the same result when the object's type, and the format are

the same.

To hint the serializer that it's safe to cache the result of these methods (and then dramatically improve the

overall performance), such normalizers (and denormalizers) should implement the

:class:`Symfony\Component\Serializer\Normalizer\CacheableSupportsMethodInterface` and return ``true`` when

:method:`Symfony\Component\Serializer\Normalizer\CacheableSupportsMethodInterface::hasCacheableSupportsMethod`

is called.

.. note::

Built-in :ref:`normalizers and denormalizers <component-serializer-normalizers>`, as well the ones

included in `API Platform`_ natively implement this interface.

.. seealso::

Normalizers for the Symfony Serializer Component supporting popular web API formats

(JSON-LD, GraphQL, HAL and JSONAPI) are available as part of the `API Platform`_ project.

.. _`API Platform`: https://api-platform.com