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feature #29167 [Messenger] Add a trait for synchronous query & comman…

…d buses (ogizanagi)

This PR was merged into the 4.2-dev branch.

Discussion
----------

[Messenger] Add a trait for synchronous query & command buses

| Q             | A
| ------------- | ---
| Branch?       | 4.2 <!-- see below -->
| Bug fix?      | no
| New feature?  | yes <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | N/A   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs/issues/10662

Commits
-------

6ba4e8a [Messenger] Add a trait for synchronous query & command buses
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nicolas-grekas committed Nov 20, 2018
2 parents ce6d918 + 6ba4e8a commit 227cf2cc22f877631eccb1881b8cdc50dd9744a4
@@ -4,6 +4,8 @@ CHANGELOG
4.2.0
-----
* Added `HandleTrait` leveraging a message bus instance to return a single
synchronous message handling result
* Added `HandledStamp` & `SentStamp` stamps
* All the changes below are BC BREAKS
* Senders and handlers subscribing to parent interfaces now receive *all* matching messages, wildcard included
@@ -0,0 +1,63 @@
<?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\Exception\LogicException;
use Symfony\Component\Messenger\Stamp\HandledStamp;
/**
* Leverages a message bus to expect a single, synchronous message handling and return its result.
*
* @author Maxime Steinhausser <maxime.steinhausser@gmail.com>
*
* @experimental in 4.2
*/
trait HandleTrait
{
/** @var MessageBusInterface */
private $messageBus;
/**
* Dispatches the given message, expecting to be handled by a single handler
* and returns the result from the handler returned value.
* This behavior is useful for both synchronous command & query buses,
* the last one usually returning the handler result.
*
* @param object|Envelope $message The message or the message pre-wrapped in an envelope
*
* @return mixed The handler returned value
*/
private function handle($message)
{
if (!$this->messageBus instanceof MessageBusInterface) {
throw new LogicException(sprintf('You must provide a "%s" instance in the "%s::$messageBus" property, "%s" given.', MessageBusInterface::class, \get_class($this), \is_object($this->messageBus) ? \get_class($this->messageBus) : \gettype($this->messageBus)));
}
$envelope = $this->messageBus->dispatch($message);
/** @var HandledStamp[] $handledStamps */
$handledStamps = $envelope->all(HandledStamp::class);
if (!$handledStamps) {
throw new LogicException(sprintf('Message of type "%s" was handled zero times. Exactly one handler is expected when using "%s::%s()".', \get_class($envelope->getMessage()), \get_class($this), __FUNCTION__));
}
if (\count($handledStamps) > 1) {
$handlers = implode(', ', array_map(function (HandledStamp $stamp): string {
return sprintf('"%s"', $stamp->getHandlerAlias() ?? $stamp->getCallableName());
}, $handledStamps));
throw new LogicException(sprintf('Message of type "%s" was handled multiple times. Only one handler is expected when using "%s::%s()", got %d: %s.', \get_class($envelope->getMessage()), \get_class($this), __FUNCTION__, \count($handledStamps), $handlers));
}
return $handledStamps[0]->getResult();
}
}
@@ -0,0 +1,97 @@
<?php
namespace Symfony\Component\Messenger\Tests;
use PHPUnit\Framework\TestCase;
use Symfony\Component\Messenger\Envelope;
use Symfony\Component\Messenger\HandleTrait;
use Symfony\Component\Messenger\MessageBus;
use Symfony\Component\Messenger\MessageBusInterface;
use Symfony\Component\Messenger\Stamp\HandledStamp;
use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
class HandleTraitTest extends TestCase
{
/**
* @expectedException \Symfony\Component\Messenger\Exception\LogicException
* @expectedExceptionMessage You must provide a "Symfony\Component\Messenger\MessageBusInterface" instance in the "Symfony\Component\Messenger\Tests\TestQueryBus::$messageBus" property, "NULL" given.
*/
public function testItThrowsOnNoMessageBusInstance()
{
$queryBus = new TestQueryBus(null);
$query = new DummyMessage('Hello');
$queryBus->query($query);
}
public function testHandleReturnsHandledStampResult()
{
$bus = $this->createMock(MessageBus::class);
$queryBus = new TestQueryBus($bus);
$query = new DummyMessage('Hello');
$bus->expects($this->once())->method('dispatch')->willReturn(
new Envelope($query, new HandledStamp('result', 'DummyHandler::__invoke'))
);
$this->assertSame('result', $queryBus->query($query));
}
public function testHandleAcceptsEnvelopes()
{
$bus = $this->createMock(MessageBus::class);
$queryBus = new TestQueryBus($bus);
$envelope = new Envelope(new DummyMessage('Hello'), new HandledStamp('result', 'DummyHandler::__invoke'));
$bus->expects($this->once())->method('dispatch')->willReturn($envelope);
$this->assertSame('result', $queryBus->query($envelope));
}
/**
* @expectedException \Symfony\Component\Messenger\Exception\LogicException
* @expectedExceptionMessage Message of type "Symfony\Component\Messenger\Tests\Fixtures\DummyMessage" was handled zero times. Exactly one handler is expected when using "Symfony\Component\Messenger\Tests\TestQueryBus::handle()".
*/
public function testHandleThrowsOnNoHandledStamp()
{
$bus = $this->createMock(MessageBus::class);
$queryBus = new TestQueryBus($bus);
$query = new DummyMessage('Hello');
$bus->expects($this->once())->method('dispatch')->willReturn(new Envelope($query));
$queryBus->query($query);
}
/**
* @expectedException \Symfony\Component\Messenger\Exception\LogicException
* @expectedExceptionMessage Message of type "Symfony\Component\Messenger\Tests\Fixtures\DummyMessage" was handled multiple times. Only one handler is expected when using "Symfony\Component\Messenger\Tests\TestQueryBus::handle()", got 2: "FirstDummyHandler::__invoke", "dummy_2".
*/
public function testHandleThrowsOnMultipleHandledStamps()
{
$bus = $this->createMock(MessageBus::class);
$queryBus = new TestQueryBus($bus);
$query = new DummyMessage('Hello');
$bus->expects($this->once())->method('dispatch')->willReturn(
new Envelope($query, new HandledStamp('first_result', 'FirstDummyHandler::__invoke'), new HandledStamp('second_result', 'SecondDummyHandler::__invoke', 'dummy_2'))
);
$queryBus->query($query);
}
}
class TestQueryBus
{
use HandleTrait;
public function __construct(?MessageBusInterface $messageBus)
{
$this->messageBus = $messageBus;
}
public function query($query): string
{
return $this->handle($query);
}
}

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