<?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;
use Symfony\Component\Messenger\Middleware\MiddlewareInterface;
use Symfony\Component\Messenger\Middleware\StackMiddleware;
/**
* @author Samuel Roze <samuel.roze@gmail.com>
* @author Matthias Noback <matthiasnoback@gmail.com>
* @author Nicolas Grekas <p@tchwork.com>
*/
class MessageBus implements MessageBusInterface
{
private $middlewareAggregate;
/**
* @param iterable<mixed, MiddlewareInterface> $middlewareHandlers
*/
public function __construct(iterable $middlewareHandlers = [])
{
if ($middlewareHandlers instanceof \IteratorAggregate) {
$this->middlewareAggregate = $middlewareHandlers;
} elseif (\is_array($middlewareHandlers)) {
$this->middlewareAggregate = new \ArrayObject($middlewareHandlers);
} else {
// $this->middlewareAggregate should be an instance of IteratorAggregate.
// When $middlewareHandlers is an Iterator, we wrap it to ensure it is lazy-loaded and can be rewound.
$this->middlewareAggregate = new class($middlewareHandlers) implements \IteratorAggregate {
private $middlewareHandlers;
private $cachedIterator;
public function __construct(\Traversable $middlewareHandlers)
{
$this->middlewareHandlers = $middlewareHandlers;
}
public function getIterator(): \Traversable
{
if (null === $this->cachedIterator) {
$this->cachedIterator = new \ArrayObject(iterator_to_array($this->middlewareHandlers, false));
}
return $this->cachedIterator;
}
};
}
}
/**
* {@inheritdoc}
*/
public function dispatch(object $message, array $stamps = []): Envelope
{
$envelope = Envelope::wrap($message, $stamps);
$middlewareIterator = $this->middlewareAggregate->getIterator();
while ($middlewareIterator instanceof \IteratorAggregate) {
$middlewareIterator = $middlewareIterator->getIterator();
}
$middlewareIterator->rewind();
if (!$middlewareIterator->valid()) {
return $envelope;
}
$stack = new StackMiddleware($middlewareIterator);
return $middlewareIterator->current()->handle($envelope, $stack);
}
}