JsonEncoder.php

<?php

namespace Drupal\serialization\Encoder;

use Symfony\Component\Serializer\Encoder\DecoderInterface;
use Symfony\Component\Serializer\Encoder\EncoderInterface;
use Symfony\Component\Serializer\Encoder\JsonDecode;
use Symfony\Component\Serializer\Encoder\JsonEncode;
use Symfony\Component\Serializer\Encoder\JsonEncoder as BaseJsonEncoder;

/**
 * Adds 'ajax to the supported content types of the JSON encoder'
 *
 * @internal
 *   This encoder should not be used directly. Rather, use the `serializer`
 *   service.
 */
class JsonEncoder extends BaseJsonEncoder implements EncoderInterface, DecoderInterface {
    
    /**
     * The formats that this Encoder supports.
     *
     * @var array
     */
    protected static $format = [
        'json',
        'ajax',
    ];
    
    /**
     * {@inheritdoc}
     */
    public function __construct(JsonEncode $encodingImpl = NULL, JsonDecode $decodingImpl = NULL) {
        $this->encodingImpl = $encodingImpl ?: $this->getJsonEncode();
        $this->decodingImpl = $decodingImpl ?: $this->getJsonDecode();
    }
    
    /**
     * Instantiates a JsonEncode instance.
     *
     * @internal this exists to bridge Symfony 3 to Symfony 4, and can be removed
     *   once Drupal requires Symfony 4.2 or higher.
     */
    private function getJsonEncode() {
        // Encode <, >, ', &, and " for RFC4627-compliant JSON, which may also be
        // embedded into HTML.
        // @see \Symfony\Component\HttpFoundation\JsonResponse
        $json_encoding_options = JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT;
        $reflection = new \ReflectionClass(JsonEncode::class);
        if (array_key_exists('OPTIONS', $reflection->getConstants())) {
            return new JsonEncode([
                JsonEncode::OPTIONS => $json_encoding_options,
            ]);
        }
        return new JsonEncode($json_encoding_options);
    }
    
    /**
     * Instantiates a JsonDecode instance.
     *
     * @internal this exists to bridge Symfony 3 to Symfony 4, and can be removed
     *   once Drupal requires Symfony 4.2 or higher.
     */
    private function getJsonDecode() {
        $reflection = new \ReflectionClass(JsonDecode::class);
        if (array_key_exists('ASSOCIATIVE', $reflection->getConstants())) {
            return new JsonDecode([
                JsonDecode::ASSOCIATIVE => TRUE,
            ]);
        }
        return new JsonDecode(TRUE);
    }
    
    /**
     * {@inheritdoc}
     */
    public function supportsEncoding($format) {
        return in_array($format, static::$format);
    }
    
    /**
     * {@inheritdoc}
     */
    public function supportsDecoding($format) {
        return in_array($format, static::$format);
    }

}