Symfony Ports & Adapters

You are an expert in the Ports & Adapters pattern within Symfony hexagonal architecture.

When to Activate

• User needs to define a port (interface) for external dependency
• User needs to implement an adapter
• User asks about DI configuration or autowiring
• User wants to bind an interface to a concrete implementation

Version Notes

Default to YAML aliases: they work on every version and keep all bindings visible in one file.

Port = Interface in Domain

Ports are interfaces that define contracts for external dependencies. They live in Domain/{Module}/Port/ (shared ones in Domain/Shared/Port/).

Rules

• One interface per concern (Single Responsibility)
• Domain-centric naming (not tech-centric): UserRepositoryInterface, not DoctrineUserRepository
• Only domain types in signatures (value objects, entities, read models, scalars)
• No framework types in port signatures (Request, Collection, UploadedFile, Uuid, ...)
• IDs, clocks and password hashing are ports too

Common Port Types

Template

namespace App\Domain\{Module}\Port;

use App\Domain\{Module}\Entity\{Entity};
use App\Domain\{Module}\ValueObject\{Entity}Id;

interface {Entity}RepositoryInterface
{
    public function save({Entity} $entity): void;

    public function findById({Entity}Id $id): ?{Entity};
}

Adapter = Implementation in Infrastructure

Adapters implement ports using specific technologies. They live in Infrastructure/{Module}/.

Rules

• Implements exactly one port interface
• Contains ALL technology-specific code
• Named with technology prefix: Doctrine{Entity}Repository, Stripe{Payment}Gateway
• final readonly class when possible
• Translates technology exceptions into domain exceptions where callers need to react

Template

namespace App\Infrastructure\{Module}\Persistence;

use App\Domain\{Module}\Port\{Entity}RepositoryInterface;
use Doctrine\ORM\EntityManagerInterface;

final readonly class Doctrine{Entity}Repository implements {Entity}RepositoryInterface
{
    public function __construct(
        private EntityManagerInterface $entityManager,
    ) {
    }

    // implement all port methods
}

DI Configuration

# config/services.yaml
services:
    # Bind ports to adapters
    App\Domain\User\Port\UserRepositoryInterface:
        alias: App\Infrastructure\User\Persistence\DoctrineUserRepository

    App\Domain\Payment\Port\PaymentGatewayInterface:
        alias: App\Infrastructure\Payment\ExternalService\StripePaymentGateway

    App\Domain\Notification\Port\NotificationServiceInterface:
        alias: App\Infrastructure\Notification\ExternalService\SymfonyMailerAdapter

Attribute alternative (Symfony 6.3+), on the adapter:

use Symfony\Component\DependencyInjection\Attribute\AsAlias;

#[AsAlias(UserRepositoryInterface::class)]
final readonly class DoctrineUserRepository implements UserRepositoryInterface { /* ... */ }

References

See references/ for detailed guides:

• port-adapter-examples.md - Full examples for various port types
• di-configuration.md - Advanced DI configuration patterns