Guide

Error provider to translate exception messages

design state

Note that we use the following configuration:

api_platform:
   defaults:
           rfc_7807_compliant_errors: true

To customize the API Platform response, replace the api_platform.state.error_provider with your own provider:

// src/App/ApiResource.php
namespace App\ApiResource;
use ApiPlatform\Metadata\ApiResource;
use ApiPlatform\Metadata\Get;
use ApiPlatform\Metadata\Operation;
use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
#[ApiResource(
    operations: [
        new Get(provider: Book::class.'::provide'),
    ],
)]
class Book
{
    public function __construct(
        public readonly int $id = 1,
        public readonly string $name = 'Anon',
    ) {
    }
    public static function provide(Operation $operation, array $uriVariables = [], array $context = []): object|array|null
    {
        throw new BadRequestHttpException('something is not right');
    }
}

// src/App/State.php
namespace App\State;
use ApiPlatform\Metadata\Operation;
use ApiPlatform\State\ApiResource\Error;
use ApiPlatform\State\ProviderInterface;

Note that we need to replace the “api_platform.state.error_provider” service, this is done later in this guide.

final class ErrorProvider implements ProviderInterface
{
    public function provide(Operation $operation, array $uriVariables = [], array $context = []): object|array|null
    {
        $request = $context['request'];
        if (!$request || !($exception = $request->attributes->get('exception'))) {
            throw new \RuntimeException();
        }
        /** @var \ApiPlatform\Metadata\HttpOperation $operation */
        $status = $operation->getStatus() ?? 500;

You don’t have to use this, you can use a Response, an array or any object (preferably a resource that API Platform can handle).

        $error = Error::createFromException($exception, $status);

care about hiding informations as this can be a security leak

        if ($status >= 500) {
            $error->setDetail('Something went wrong');
        } else {

You can handle translation here with the Translator

            $error->setDetail(str_replace('something is not right', 'les calculs ne sont pas bons', $exception->getMessage()));
        }
        return $error;
    }
}

This is replacing the service, the “key” is important as this is the provider we will look for when handling an exception.

// src/App/DependencyInjection.php
namespace App\DependencyInjection;
use App\State\ErrorProvider;
use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
function configure(ContainerConfigurator $configurator): void
{
    $services = $configurator->services();
    $services->set('api_platform.state.error_provider')
        ->class(ErrorProvider::class)
        ->tag('api_platform.state_provider', ['key' => 'api_platform.state.error_provider']);
}

// src/App/Tests.php
namespace App\Tests;
use ApiPlatform\Playground\Test\TestGuideTrait;
use ApiPlatform\Symfony\Bundle\Test\ApiTestCase;
final class BookTest extends ApiTestCase
{
    use TestGuideTrait;
    public function testBookDoesNotExists(): void
    {
        static::createClient()->request('GET', '/books/1', options: ['headers' => ['accept' => 'application/ld+json']]);
        $this->assertResponseStatusCodeSame(400);
        $this->assertJsonContains([
            'detail' => 'les calculs ne sont pas bons'
        ]);
    }
}

// src/App/Playground.php
namespace App\Playground;
use Symfony\Component\HttpFoundation\Request;
function request(): Request
{
    return Request::create('/books/1.jsonld', 'GET');
}

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