commandbus.md

CommandBus

The main command bus implementation that orchestrates command processing through a middleware pipeline.

Overview

CommandBus is the primary entry point for command processing. It accepts commands and delegates their execution to a configured middleware pipeline. This class provides a clean interface for command dispatch while allowing flexible middleware composition.

Class Definition

final class CommandBus implements CommandBusInterface
{
    public function __construct(
        private MiddlewarePipelineInterface&MiddlewarePipe $pipeline
    ) {}

    public function handle(CommandInterface $command): mixed
    {
        return $this->pipeline->handle($command);
    }
}

Constructor Parameters

• $pipeline - A middleware pipeline that implements both MiddlewarePipelineInterface and is an instance of MiddlewarePipe

Methods

handle(CommandInterface $command): mixed

Processes a command through the configured middleware pipeline.

Parameters:

• $command - The command to process

Returns:

• mixed - The result from the command processing pipeline

Usage Examples

Basic Usage in Mezzio

use App\Command\CreateUserCommand;
use Laminas\Diactoros\Response\JsonResponse;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Webware\CommandBus\CommandBusInterface;
use Webware\CommandBus\Command\CommandResult;

final readonly class CreateUserRequestHandler implements RequestHandlerInterface
{
    public function __construct(
        private CommandBusInterface $commandBus
    ) {}

    public function handle(ServerRequestInterface $request): ResponseInterface
    {
        $command = new CreateUserCommand(
            email: 'user@example.com',
            username: 'newuser'
        );

        /** @var CommandResult $commandResult */
        $commandResult = $this->commandBus->handle($command);

        return match ($result->getStatus()) {
            CommandResult::Success => new JsonResponse(['user_id' => $result->getResult()]),
            CommandResult::Failure => new JsonResponse(['message' => 'Command Failure']),
            default => throw new \YourException('Some custom message'),
        };
    }
}

Related Components

• CommandBusInterface - The interface this class implements
• MiddlewarePipe - The pipeline component used internally
• CommandBusFactory - Factory for creating instances
• CommandInterface - Interface all commands must implement