MarkupNormalizer.php

<?php

namespace Drupal\serialization\Normalizer;

use Drupal\Component\Render\MarkupInterface;

/**
 * Normalizes MarkupInterface objects into a string.
 */
class MarkupNormalizer extends NormalizerBase {
    use SchematicNormalizerTrait;
    use JsonSchemaReflectionTrait;
    
    /**
     * {@inheritdoc}
     */
    public function doNormalize($object, $format = NULL, array $context = []) : array|string|int|float|bool|\ArrayObject|null {
        return (string) $object;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getNormalizationSchema(mixed $object, array $context = []) : array {
        return $this->getJsonSchemaForMethod($object, '__toString', [
            'type' => 'string',
            'description' => 'May contain HTML markup.',
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSupportedTypes(?string $format) : array {
        return [
            MarkupInterface::class => TRUE,
        ];
    }

}