<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\Messenger\Middleware;
use Symfony\Component\Messenger\Bridge\Amqp\Transport\AmqpReceivedStamp;
use Symfony\Component\Messenger\Envelope;
use Symfony\Component\Messenger\Exception\RejectRedeliveredMessageException;
/**
* Middleware that throws a RejectRedeliveredMessageException when a message is detected that has been redelivered by AMQP.
*
* The middleware runs before the HandleMessageMiddleware and prevents redelivered messages from being handled directly.
* The thrown exception is caught by the worker and will trigger the retry logic according to the retry strategy.
*
* AMQP redelivers messages when they do not get acknowledged or rejected. This can happen when the connection times out
* or an exception is thrown before acknowledging or rejecting. When such errors happen again while handling the
* redelivered message, the message would get redelivered again and again. The purpose of this middleware is to prevent
* infinite redelivery loops and to unblock the queue by republishing the redelivered messages as retries with a retry
* limit and potential delay.
*
* @author Tobias Schultze <http://tobion.de>
*/
class RejectRedeliveredMessageMiddleware implements MiddlewareInterface
{
public function handle(Envelope $envelope, StackInterface $stack): Envelope
{
$amqpReceivedStamp = $envelope->last(AmqpReceivedStamp::class);
if ($amqpReceivedStamp instanceof AmqpReceivedStamp && $amqpReceivedStamp->getAmqpEnvelope()->isRedelivery()) {
throw new RejectRedeliveredMessageException('Redelivered message from AMQP detected that will be rejected and trigger the retry logic.');
}
return $stack->next()->handle($envelope, $stack);
}
}