How to Create Your own Messenger Transport
==========================================
Once you have written your transport's sender and receiver, you can register your
transport factory to be able to use it via a DSN in the Symfony application.
Create your Transport Factory
-----------------------------
You need to give FrameworkBundle the opportunity to create your transport from a
DSN. You will need a transport factory::
use Symfony\Component\Messenger\Transport\Receiver\ReceiverInterface;
use Symfony\Component\Messenger\Transport\Sender\SenderInterface;
use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
use Symfony\Component\Messenger\Transport\TransportFactoryInterface;
use Symfony\Component\Messenger\Transport\TransportInterface;
class YourTransportFactory implements TransportFactoryInterface
{
public function createTransport(string $dsn, array $options, SerializerInterface $serializer): TransportInterface
{
return new YourTransport(/* ... */);
}
public function supports(string $dsn, array $options): bool
{
return 0 === strpos($dsn, 'my-transport://');
}
}
The transport object needs to implement the
:class:`Symfony\\Component\\Messenger\\Transport\\TransportInterface`
(which combines the :class:`Symfony\\Component\\Messenger\\Transport\\Sender\\SenderInterface`
and :class:`Symfony\\Component\\Messenger\\Transport\\Receiver\\ReceiverInterface`).
Here is a simplified example of a database transport::
use Ramsey\Uuid\Uuid;
use Symfony\Component\Messenger\Envelope;
use Symfony\Component\Messenger\Stamp\TransportMessageIdStamp;
use Symfony\Component\Messenger\Transport\Serialization\PhpSerializer;
use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
use Symfony\Component\Messenger\Transport\TransportInterface;
class YourTransport implements TransportInterface
{
private $db;
private $serializer;
/**
* @param FakeDatabase $db is used for demo purposes. It is not a real class.
*/
public function __construct(FakeDatabase $db, SerializerInterface $serializer = null)
{
$this->db = $db;
$this->serializer = $serializer ?? new PhpSerializer();
}
public function get(): iterable
{
// Get a message from "my_queue"
$row = $this->db->createQuery(
'SELECT *
FROM my_queue
WHERE (delivered_at IS NULL OR delivered_at < :redeliver_timeout)
AND handled = FALSE'
)
->setParameter('redeliver_timeout', new DateTimeImmutable('-5minutes'))
->getOneOrNullResult();
if (null === $row) {
return [];
}
$envelope = $this->serializer->decode([
'body' => $row['envelope'],
]);
return [$envelope->with(new TransportMessageIdStamp($row['id']))];
}
public function ack(Envelope $envelope): void
{
$stamp = $envelope->last(TransportMessageIdStamp::class);
if (!$stamp instanceof TransportMessageIdStamp) {
throw new \LogicException('No TransportMessageIdStamp found on the Envelope.');
}
// Mark the message as "handled"
$this->db->createQuery('UPDATE my_queue SET handled = TRUE WHERE id = :id')
->setParameter('id', $stamp->getId())
->execute();
}
public function reject(Envelope $envelope): void
{
$stamp = $envelope->last(TransportMessageIdStamp::class);
if (!$stamp instanceof TransportMessageIdStamp) {
throw new \LogicException('No TransportMessageIdStamp found on the Envelope.');
}
// Delete the message from the "my_queue" table
$this->db->createQuery('DELETE FROM my_queue WHERE id = :id')
->setParameter('id', $stamp->getId())
->execute();
}
public function send(Envelope $envelope): Envelope
{
$encodedMessage = $this->serializer->encode($envelope);
$uuid = Uuid::uuid4()->toString();
// Add a message to the "my_queue" table
$this->db->createQuery(
'INSERT INTO my_queue (id, envelope, delivered_at, handled)
VALUES (:id, :envelope, NULL, FALSE)'
)
->setParameters([
'id' => $uuid,
'envelope' => $encodedMessage['body'],
])
->execute();
return $envelope->with(new TransportMessageIdStamp($uuid));
}
}
The implementation above is not runnable code but illustrates how a
:class:`Symfony\\Component\\Messenger\\Transport\\TransportInterface` could
be implemented. For real implementations see :class:`Symfony\\Component\\Messenger\\Transport\\InMemoryTransport`
and :class:`Symfony\\Component\\Messenger\\Transport\\Doctrine\\DoctrineReceiver`.
Register your Factory
---------------------
.. configuration-block::
.. code-block:: yaml
# config/services.yaml
services:
Your\Transport\YourTransportFactory:
tags: [messenger.transport_factory]
.. code-block:: xml
.. code-block:: php
// config/services.php
use Your\Transport\YourTransportFactory;
$container->register(YourTransportFactory::class)
->setTags(['messenger.transport_factory']);
Use your Transport
------------------
Within the ``framework.messenger.transports.*`` configuration, create your
named transport using your own DSN:
.. configuration-block::
.. code-block:: yaml
# config/packages/messenger.yaml
framework:
messenger:
transports:
yours: 'my-transport://...'
.. code-block:: xml
.. code-block:: php
// config/packages/messenger.php
$container->loadFromExtension('framework', [
'messenger' => [
'transports' => [
'yours' => 'my-transport://...',
],
],
]);
In addition of being able to route your messages to the ``yours`` sender, this
will give you access to the following services:
#. ``messenger.sender.yours``: the sender;
#. ``messenger.receiver.yours``: the receiver.