Creating Consumers
==================

Let's assume you have an amqp message which will be published when an order has been created. This message has
the routing key ``order-created`` with the payload ``{"order_id": 42}``. In this example we create a consumer
which sends an email to the customer when this message will be published.

First of all, you have to create a PHP class which represents this message::

    namespace My\Consumer;

    use JMS\Serializer\Attribute\Type;
    use Rebuy\Amqp\Consumer\Message\MessageInterface;

    class OrderCreatedMessage implements MessageInterface
    {
        /**
         * @var array<int>
         */
         #[Type('array<integer>')]
        public array $orderId;

        public static function getRoutingKey(): string
        {
            return 'order-created';
        }
    }

.. note::
    In this example we use the `jms/serializer`_ component to deserialize the payload for all messages, so we have to
    define a ``#[Type]`` for the property ``$orderId``.

With this message we are able to create our consumer which will send an email to the customer::

    class OrderConsumer
    {
        public function __construct(private readonly OrderService $orderService, private readonly EmailService $emailService)
        {
        }

        #[Consumer(name: 'order-created-send-email')]
        public function sendMail(OrderCreatedMessage $message): void
        {
            $order = $this->orderService->loadOrder($message->orderId);
            $this->emailService->sendOrderCreatedEmail($order);
        }
    }

.. note::
    You can create multiple consumers which consume the same message, but they must use a different name, otherwise
    an ``ConsumerException`` is thrown.


Now that you have created a consumer, you can go on to the next section and create the
:doc:`consumer manager <consumer-manager>`


.. _jms/serializer: http://jmsyst.com/libs/serializer