Agent skill
symfony-cqrs-handlers
Symfony CQRS command/query handlers — commands, queries, handlers, bus configuration, use cases. Triggers on: command, query, handler, CQRS, bus, use case, command handler, query handler, message bus
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/symfony-cqrs-handlers
SKILL.md
Symfony CQRS Handlers
You are an expert in CQRS (Command Query Responsibility Segregation) within Symfony hexagonal architecture.
When to Activate
- User wants to create a command or query
- User needs a handler for a use case
- User asks about CQRS patterns or message bus configuration
- User mentions "use case", "action", "operation" in application context
Command Pattern
Commands represent write operations (create, update, delete). They are DTOs dispatched to the command bus.
Rules
final readonly class— immutable after construction- Named as imperative verb:
RegisterUser,PlaceOrder,CancelSubscription - Contains only primitive types and value objects — no entities
- Handler returns
voidor a scalar identifier (string ID) - One handler per command
Template
namespace App\Application\{Module}\Command;
final readonly class {ActionVerb}{Entity}
{
public function __construct(
public string $param1,
public string $param2,
// only primitives and simple types
) {
}
}
Handler Template
namespace App\Application\{Module}\Command;
use App\Domain\{Module}\Port\{Repository}Interface;
use Symfony\Component\Messenger\Attribute\AsMessageHandler;
#[AsMessageHandler(bus: 'command.bus')]
final readonly class {ActionVerb}{Entity}Handler
{
public function __construct(
private {Repository}Interface $repository,
) {
}
public function __invoke({ActionVerb}{Entity} $command): void
{
// 1. Reconstruct/create domain objects
// 2. Execute business logic
// 3. Persist via port
// NO side-effects here — use domain events
}
}
Query Pattern
Queries represent read operations. They return DTOs, never domain entities.
Rules
final readonly class— immutable- Named descriptively:
GetUserById,ListActiveOrders,SearchProducts - Handler MUST return a DTO or array of DTOs
- Handler NEVER modifies state
- May use read-optimized ports (separate from write ports)
Template
namespace App\Application\{Module}\Query;
final readonly class {GetDescription}
{
public function __construct(
public string $identifier,
// filter/pagination params
) {
}
}
Handler Template
namespace App\Application\{Module}\Query;
use App\Application\{Module}\DTO\{Entity}DTO;
use App\Domain\{Module}\Port\{Repository}Interface;
use Symfony\Component\Messenger\Attribute\AsMessageHandler;
#[AsMessageHandler(bus: 'query.bus')]
final readonly class {GetDescription}Handler
{
public function __construct(
private {Repository}Interface $repository,
) {
}
public function __invoke({GetDescription} $query): ?{Entity}DTO
{
$entity = $this->repository->findById($query->identifier);
if ($entity === null) {
return null;
}
return {Entity}DTO::fromEntity($entity);
}
}
DTO Pattern
namespace App\Application\{Module}\DTO;
final readonly class {Entity}DTO
{
public function __construct(
public string $id,
public string $field1,
public string $field2,
) {
}
public static function fromEntity(/* entity */): self
{
return new self(
id: (string) $entity->id(),
field1: $entity->field1(),
field2: $entity->field2(),
);
}
}
References
See references/ for detailed guides:
command-patterns.md— Full command examples with validationquery-patterns.md— Query patterns with pagination and filteringbus-configuration.md— Messenger bus setup and middleware
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