class Serializer

1. 8.x drupal/core/vendor/symfony/serializer/Symfony/Component/Serializer/Serializer.php \Symfony\Component\Serializer\Serializer
2. 8.x drupal/core/modules/rest/lib/Drupal/rest/Plugin/views/style/Serializer.php \Drupal\rest\Plugin\views\style\Serializer

class Serializer extends StylePluginBase {

  /**
   * Overrides \Drupal\views\Plugin\views\style\StylePluginBase::$usesRowPlugin.
   */
  protected $usesRowPlugin = TRUE;

  /**
   * Overrides Drupal\views\Plugin\views\style\StylePluginBase::$usesFields.
   */
  protected $usesGrouping = FALSE;

  /**
   * The serializer which serializes the views result.
   *
   * @var \Symfony\Component\Serializer\Serializer
   */
  protected $serializer;

  /**
   * The available serialization formats.
   *
   * @var array
   */
  protected $formats = array();

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, array $plugin_definition) {
    return new static($configuration, $plugin_id, $plugin_definition, $container
      ->get('serializer'), $container
      ->getParameter('serializer.formats'));
  }

  /**
   * Constructs a Plugin object.
   */
  public function __construct(array $configuration, $plugin_id, array $plugin_definition, SerializerInterface $serializer, array $serializer_formats) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->definition = $plugin_definition + $configuration;
    $this->serializer = $serializer;
    $this->formats = $serializer_formats;
  }

  /**
   * {@inheritdoc}
   */
  protected function defineOptions() {
    $options = parent::defineOptions();
    $options['formats'] = array(
      'default' => array(),
    );
    return $options;
  }

  /**
   * {@inheritdoc}
   */
  public function buildOptionsForm(&$form, &$form_state) {
    parent::buildOptionsForm($form, $form_state);
    $form['formats'] = array(
      '#type' => 'checkboxes',
      '#title' => t('Accepted request formats'),
      '#description' => t('Request formats that will be allowed in responses. If none are selected all formats will be allowed.'),
      '#options' => drupal_map_assoc($this->formats),
      '#default_value' => $this->options['formats'],
    );
  }

  /**
   * {@inheritdoc}
   */
  public function submitOptionsForm(&$form, &$form_state) {
    parent::submitOptionsForm($form, $form_state);
    $form_state['values']['style_options']['formats'] = array_filter($form_state['values']['style_options']['formats']);
  }

  /**
   * {@inheritdoc}
   */
  public function render() {
    $rows = array();

    // If the Data Entity row plugin is used, this will be an array of entities
    // which will pass through Serializer to one of the registered Normalizers,
    // which will transform it to arrays/scalars. If the Data field row plugin
    // is used, $rows will not contain objects and will pass directly to the
    // Encoder.
    foreach ($this->view->result as $row) {
      $rows[] = $this->view->rowPlugin
        ->render($row);
    }
    return $this->serializer
      ->serialize($rows, $this->displayHandler
      ->getContentType());
  }

  /**
   * Gets a list of all available formats that can be requested.
   *
   * This will return the configured formats, or all formats if none have been
   * selected.
   *
   * @return array
   *   An array of formats.
   */
  public function getFormats() {
    if (!empty($this->options['formats'])) {
      return $this->options['formats'];
    }
    return $this->formats;
  }

}