Is there a way to add filters to custom endpoint with DTO?

Question

I have a custom endpoint (which does some custom aggregations), the return of this endpoint is a collection of DTO. I want to add some filters sugestions for the consumers of my api. Is this possible ? How can you do that ?

To sum up :

• I have a DTO (ApiResource but not linked to doctrine or a database).
• I have a custom GET endpoint that return a collection of DTO (filtered or not).
• I want to add filters sugestion to this endpoint.

Should i modify the hydra:search somehow ?

I tried to add ApiFilters (like i do for the entites) on my DTO but ApiFilters are linked to doctrine so it gives me the following error : Call to a member function getClassMetadata() on null on vendor/api-platform/core/src/Bridge/Doctrine/Common/PropertyHelperTrait.php

Answer 1

I encountered the same issue, to solve it I create a custom filter without the $this->isPropertyMapped part.

I injected the ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\FilterExtension to my collection provider and apply my filters with $this->filterExtension->applyToCollection($qb, $queryNameGenerator, $resourceClass, $operationName, $context); in order to alter the query.

Then I just need to configure my custom filter in my dto object

@ApiFilter(SearchFilter::class, properties={"columnName": "exact"})

<?php

declare(strict_types=1);

namespace App\ThirdParty\ApiPlatform\Filter;

use ApiPlatform\Core\Bridge\Doctrine\Orm\Filter\AbstractContextAwareFilter;
use ApiPlatform\Core\Bridge\Doctrine\Orm\Util\QueryNameGeneratorInterface;
use Doctrine\ORM\QueryBuilder;

final class SearchFilter extends AbstractContextAwareFilter
{

    protected function filterProperty(
        string $property,
        $value,
        QueryBuilder $queryBuilder,
        QueryNameGeneratorInterface $queryNameGenerator,
        string $resourceClass,
        string $operationName = null
    ): void {
        if (
            !$this->isPropertyEnabled($property, $resourceClass)
        ) {
            return;
        }

        $parameterName = $queryNameGenerator->generateParameterName($property);

        $rootAlias = $queryBuilder->getRootAliases()[0];

        $queryBuilder
            ->andWhere(sprintf('%s.%s = :%s', $rootAlias, $property, $parameterName))
            ->setParameter($parameterName, $value);
    }

    public function getDescription(string $resourceClass): array
    {
        if (!$this->properties) {
            return [];
        }

        $description = [];
        foreach ($this->properties as $property => $strategy) {
            $description["regexp_$property"] = [
                'property' => $property,
                'type' => 'string',
                'required' => false,
                'swagger' => [
                    'description' => 'description',
                    'name' => $property,
                    'type' => 'type',
                ],
            ];
        }

        return $description;
    }
}