simple command middleware implementation using prooph components

CommandMiddleware.php

<?php

declare(strict_types = 1);

namespace Acme\Middleware;

use Interop\Http\ServerMiddleware\DelegateInterface;
use Interop\Http\ServerMiddleware\MiddlewareInterface;
use Prooph\Common\Messaging\MessageFactory;
use Prooph\Psr7Middleware\MetadataGatherer;
use Prooph\ServiceBus\CommandBus;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Zend\Diactoros\Response\JsonResponse;

final class CommandMiddleware implements MiddlewareInterface
{
    private $commandBus;
    private $commandFactory;
    private $metadataGatherer;
    private $commands;

    public function __construct(
        CommandBus $commandBus,
        MessageFactory $commandFactory,
        MetadataGatherer $metadataGatherer,
        array $commands
    ) {
        $this->commandBus = $commandBus;
        $this->commandFactory = $commandFactory;
        $this->metadataGatherer = $metadataGatherer;
        $this->commands = $commands;
    }

    public function process(ServerRequestInterface $request, DelegateInterface $delegate): ResponseInterface
    {
        $command = $request->getAttribute('command');
        $commandClass = $this->commands[$command];

        $command = $this->commandFactory->createMessageFromArray($commandClass, [
            'payload' => (array) $request->getParsedBody(),
            'metadata' => $this->metadataGatherer->getFromRequest($request),
        ]);

        $this->commandBus->dispatch($command);

        return new JsonResponse(['success' => true]);
    }
}