README

Command Query Responsibility Segregation: CommandBus, QueryBus, Handlers, and Middleware.

Commands produce side effects and return nothing. Queries return data and produce no side effects.

Installation

composer require solidframe/cqrs

Quick Start

Define a Command and Handler

use SolidFrame\Cqrs\Command;
use SolidFrame\Cqrs\CommandHandler;

final readonly class PlaceOrder implements Command
{
    public function __construct(
        public string $orderId,
        public string $customerId,
    ) {}
}

final readonly class PlaceOrderHandler implements CommandHandler
{
    public function __construct(private OrderRepository $orders) {}

    public function __invoke(PlaceOrder $command): void
    {
        $order = Order::place(
            new OrderId($command->orderId),
            new CustomerId($command->customerId),
        );

        $this->orders->save($order);
    }
}

Define a Query and Handler

use SolidFrame\Cqrs\Query;
use SolidFrame\Cqrs\QueryHandler;

final readonly class GetOrderById implements Query
{
    public function __construct(public string $orderId) {}
}

final readonly class GetOrderByIdHandler implements QueryHandler
{
    public function __construct(private OrderRepository $orders) {}

    public function __invoke(GetOrderById $query): ?OrderDto
    {
        $order = $this->orders->find(new OrderId($query->orderId));

        return $order ? OrderDto::fromEntity($order) : null;
    }
}

Dispatch

// Command — fire and forget
$commandBus->dispatch(new PlaceOrder(
    orderId: 'order-123',
    customerId: 'customer-456',
));

// Query — get result
$order = $queryBus->ask(new GetOrderById(orderId: 'order-123'));

Standalone Usage

Without a framework bridge, wire the bus manually:

use SolidFrame\Cqrs\Handler\InMemoryHandlerResolver;
use SolidFrame\Cqrs\Bus\CommandBus;
use SolidFrame\Cqrs\Bus\QueryBus;

$resolver = new InMemoryHandlerResolver();
$resolver->register(PlaceOrder::class, new PlaceOrderHandler($orders));

$commandBus = new CommandBus($resolver);
$commandBus->dispatch(new PlaceOrder('order-123', 'customer-456'));

Middleware

Add cross-cutting concerns to bus processing.

use SolidFrame\Core\Middleware\MiddlewareInterface;

final readonly class TransactionMiddleware implements MiddlewareInterface
{
    public function __construct(private Connection $connection) {}

    public function handle(object $message, callable $next): mixed
    {
        $this->connection->beginTransaction();

        try {
            $result = $next($message);
            $this->connection->commit();

            return $result;
        } catch (\Throwable $e) {
            $this->connection->rollBack();
            throw $e;
        }
    }
}

// With middleware
$commandBus = new CommandBus($resolver, [
    new TransactionMiddleware($connection),
    new LoggingMiddleware($logger),
]);

Middleware executes in registration order. Each middleware calls $next($message) to pass to the next one.

Handler Resolution

Handlers are resolved by the message type passed to __invoke(). The convention:

• PlaceOrder command → PlaceOrderHandler::__invoke(PlaceOrder $command)
• GetOrderById query → GetOrderByIdHandler::__invoke(GetOrderById $query)

One handler per command/query. Multiple handlers for the same message type will throw an exception.

API Reference

Related Packages

• solidframe/core — Bus interfaces, Middleware contract
• solidframe/ddd — Entities and aggregates your handlers operate on
• solidframe/event-driven — Dispatch domain events after commands
• solidframe/laravel — Auto-discovery, DI, make:cqrs-command, make:query
• solidframe/symfony — Compiler pass, DI, same generators

Contributing

This repository is a read-only split of the solidframe/solidframe monorepo, auto-synced on every push to main. Issues, pull requests, and discussions belong in the monorepo.