[JsonStreamer] Provide current object to value transformers #61006
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Indeed this is really a nice-to-have functionality. When generating Hypermedia (or probably any JSON) while streaming, it's quite useful to have the current object being serialized to change parts of the data. To illustrate, we use it to generate the IRI of a given object during serialization: <?php
declare(strict_types=1);
namespace ApiPlatform\JsonLd\JsonStreamer\ValueTransformer;
use ApiPlatform\Hydra\Collection;
use ApiPlatform\Metadata\CollectionOperationInterface;
use ApiPlatform\Metadata\IriConverterInterface;
use ApiPlatform\Metadata\UrlGeneratorInterface;
use Symfony\Component\JsonStreamer\ValueTransformer\ValueTransformerInterface;
use Symfony\Component\TypeInfo\Type;
final class IriValueTransformer implements ValueTransformerInterface
{
public function __construct(
private readonly IriConverterInterface $iriConverter,
) {
}
public function transform(mixed $value, array $options = []): mixed
{
if ($options['_current_object'] instanceof Collection) {
return $this->iriConverter->getIriFromResource($options['operation']->getClass(), UrlGeneratorInterface::ABS_PATH, $options['operation']);
}
return $this->iriConverter->getIriFromResource(
$options['_current_object'],
UrlGeneratorInterface::ABS_PATH,
$options['operation'] instanceof CollectionOperationInterface ? null : $options['operation'],
);
}
public static function getStreamValueType(): Type
{
return Type::string();
}
}Without this functionality we're quite locked-out when it comes to transformations like this one: it's recursive so we're using only the node being serialized, as opposed to |
| @@ -6,13 +6,13 @@ | |||
| return static function (mixed $data, \Psr\Container\ContainerInterface $valueTransformers, array $options): \Traversable { | |||
| try { | |||
| yield '{"id":'; | |||
| yield \json_encode($valueTransformers->get('Symfony\Component\JsonStreamer\Tests\Fixtures\ValueTransformer\DoubleIntAndCastToStringValueTransformer')->transform($data->id, $options), \JSON_THROW_ON_ERROR, 511); | |||
| yield \json_encode($valueTransformers->get('Symfony\Component\JsonStreamer\Tests\Fixtures\ValueTransformer\DoubleIntAndCastToStringValueTransformer')->transform($data->id, $options + ['_current_object' => $data]), \JSON_THROW_ON_ERROR, 511); | |||
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can the addition be done earlier so that it's done once?
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I'm not sure that it's the best way to go here.
Indeed, storing the current object earlier will do variable assignments for nothing if the is no value transformer. For example, for this object with nested objects, it'll do 4 variable assignment for "nothing" (and it'll be even worse if it is a collection of that object):
/**
* @param Symfony\Component\JsonStreamer\Tests\Fixtures\Model\DummyWithOtherDummies $data
*/
return static function (mixed $data, \Psr\Container\ContainerInterface $valueTransformers, array $options): \Traversable {
try {
$options['_current_object'] = $data;
yield '{"name":';
yield \json_encode($data->name, \JSON_THROW_ON_ERROR, 511);
$options['_current_object'] = $data->otherDummyOne;
yield ',"otherDummyOne":{"@id":';
yield \json_encode($data->otherDummyOne->id, \JSON_THROW_ON_ERROR, 510);
yield ',"name":';
yield \json_encode($data->otherDummyOne->name, \JSON_THROW_ON_ERROR, 510);
$options['_current_object'] = $data->otherDummyTwo;
yield '},"otherDummyTwo":{"id":';
yield \json_encode($data->otherDummyTwo->id, \JSON_THROW_ON_ERROR, 510);
yield ',"name":';
yield \json_encode($data->otherDummyTwo->name, \JSON_THROW_ON_ERROR, 510);
$options['_current_object'] = $data;
yield '},"friendly":';
yield $data->friendly ? 'true' : 'false';
yield '}';
} catch (\JsonException $e) {
throw new \Symfony\Component\JsonStreamer\Exception\NotEncodableValueException($e->getMessage(), 0, $e);
}
};Plus, it kind of introduce "state" that is a bit risky to me. With the variable assignment, we have more chance to mess up and forget to set/reset the current object, while the array addition is 100% sure.
WDYT?
mtarld
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Indeed, I changed Good idea for the doc block, I added the comment. |
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PR title reads weird 😅 |
mtarld
changed the title
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Indeed 😅. I updated it, does it look better to you? |
A new attempt to #59281.
As discussed with @soyuka, it is really important to have access to the current object during stream writing.
Without that, it'll for example be impossible for API Platform to generate resource IRIs (https://github.com/api-platform/core/blob/main/src/Metadata/IriConverterInterface.php#L46).
This PR makes is available in value transformers'
$contextunder the_current_objectkey.