[Messenger] remove AllowNoHandlerMiddleware in favor of a constructor argument on HandleMessageMiddleware

Author: nicolas-grekas

CHANGELOG.md

@@ -30,7 +30,7 @@ CHANGELOG
  * `SenderLocatorInterface::getSenderForMessage()` has been replaced by `getSender(Envelope $envelope)`
  * `MessengerDataCollector::getMessages()` returns an iterable, not just an array anymore
  * `AbstractHandlerLocator` is now internal
- * `HandlerLocatorInterface::resolve()` has been replaced by `getHandler(Envelope $envelope)`
+ * `HandlerLocatorInterface::resolve()` has been replaced by `getHandler(Envelope $envelope): ?callable` and shouldn't throw when no handlers are found
  * `SenderLocatorInterface::getSenderForMessage()` has been replaced by `getSender(Envelope $envelope)`
  * `SenderInterface::send()` returns `void`
  * Classes in the `Middleware\Enhancers` sub-namespace have been moved to the `Middleware` one
@@ -39,6 +39,7 @@ CHANGELOG
  * `SenderInterface` and `ChainSender` classes have been moved to the `Transport\Sender` sub-namespace
  * `ReceiverInterface` and its implementations have been moved to the `Transport\Receiver` sub-namespace
  * `ActivationMiddlewareDecorator` has been renamed `ActivationMiddleware`
+ * `AllowNoHandlerMiddleware` has been removed in favor of a new constructor argument on `HandleMessageMiddleware`
 
 4.1.0
 -----

Handler/Locator/AbstractHandlerLocator.php

@@ -12,7 +12,6 @@
 namespace Symfony\Component\Messenger\Handler\Locator;
 
 use Symfony\Component\Messenger\Envelope;
-use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
 
 /**
  * @author Miha Vrhovnik <[email protected]>
@@ -22,7 +21,7 @@
  */
 abstract class AbstractHandlerLocator implements HandlerLocatorInterface
 {
-    public function getHandler(Envelope $envelope): callable
+    public function getHandler(Envelope $envelope): ?callable
     {
         $class = \get_class($envelope->getMessage());
 
@@ -42,7 +41,7 @@ public function getHandler(Envelope $envelope): callable
             }
         }
 
-        throw new NoHandlerForMessageException(sprintf('No handler for message "%s".', $class));
+        return null;
     }
 
     abstract protected function getHandlerByName(string $name): ?callable;

Handler/Locator/HandlerLocatorInterface.php

@@ -12,7 +12,6 @@
 namespace Symfony\Component\Messenger\Handler\Locator;
 
 use Symfony\Component\Messenger\Envelope;
-use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
 
 /**
  * @author Samuel Roze <[email protected]>
@@ -21,8 +20,6 @@ interface HandlerLocatorInterface
 {
     /**
      * Returns the handler for the given message.
-     *
-     * @throws NoHandlerForMessageException When no handler is found
      */
-    public function getHandler(Envelope $envelope): callable;
+    public function getHandler(Envelope $envelope): ?callable;
 }

Middleware/AllowNoHandlerMiddleware.php

@@ -12,6 +12,7 @@
 namespace Symfony\Component\Messenger\Middleware;
 
 use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
 use Symfony\Component\Messenger\Handler\Locator\HandlerLocatorInterface;
 
 /**
@@ -20,19 +21,26 @@
 class HandleMessageMiddleware implements MiddlewareInterface
 {
     private $messageHandlerLocator;
+    private $allowNoHandlers;
 
-    public function __construct(HandlerLocatorInterface $messageHandlerLocator)
+    public function __construct(HandlerLocatorInterface $messageHandlerLocator, bool $allowNoHandlers = false)
     {
         $this->messageHandlerLocator = $messageHandlerLocator;
+        $this->allowNoHandlers = $allowNoHandlers;
     }
 
     /**
      * {@inheritdoc}
+     *
+     * @throws NoHandlerForMessageException When no handler is found and $allowNoHandlers is false
      */
     public function handle(Envelope $envelope, callable $next): void
     {
-        $handler = $this->messageHandlerLocator->getHandler($envelope);
-        $handler($envelope->getMessage());
-        $next($envelope);
+        if (null !== $handler = $this->messageHandlerLocator->getHandler($envelope)) {
+            $handler($envelope->getMessage());
+            $next($envelope);
+        } elseif (!$this->allowNoHandlers) {
+            throw new NoHandlerForMessageException(sprintf('No handler for message "%s".', \get_class($envelope->getMessage())));
+        }
     }
 }

Middleware/HandleMessageMiddleware.php

@@ -27,7 +27,6 @@
 use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
 use Symfony\Component\Messenger\Handler\MessageSubscriberInterface;
 use Symfony\Component\Messenger\MessageBusInterface;
-use Symfony\Component\Messenger\Middleware\AllowNoHandlerMiddleware;
 use Symfony\Component\Messenger\Middleware\HandleMessageMiddleware;
 use Symfony\Component\Messenger\Middleware\MiddlewareInterface;
 use Symfony\Component\Messenger\Tests\Fixtures\DummyCommand;
@@ -493,7 +492,6 @@ public function testRegistersTraceableBusesToCollector()
     public function testRegistersMiddlewareFromServices()
     {
         $container = $this->getContainerBuilder($fooBusId = 'messenger.bus.foo');
-        $container->register('messenger.middleware.allow_no_handler', AllowNoHandlerMiddleware::class)->setAbstract(true);
         $container->register('middleware_with_factory', UselessMiddleware::class)->addArgument('some_default')->setAbstract(true);
         $container->register('middleware_with_factory_using_default', UselessMiddleware::class)->addArgument('some_default')->setAbstract(true);
         $container->register(UselessMiddleware::class, UselessMiddleware::class);
@@ -502,14 +500,11 @@ public function testRegistersMiddlewareFromServices()
             array('id' => UselessMiddleware::class),
             array('id' => 'middleware_with_factory', 'arguments' => array('foo', 'bar')),
             array('id' => 'middleware_with_factory_using_default'),
-            array('id' => 'allow_no_handler'),
         ));
 
         (new MessengerPass())->process($container);
         (new ResolveChildDefinitionsPass())->process($container);
 
-        $this->assertTrue($container->hasDefinition($childMiddlewareId = $fooBusId.'.middleware.allow_no_handler'));
-
         $this->assertTrue($container->hasDefinition($factoryChildMiddlewareId = $fooBusId.'.middleware.middleware_with_factory'));
         $this->assertEquals(
             array('foo', 'bar'),
@@ -528,7 +523,6 @@ public function testRegistersMiddlewareFromServices()
             new Reference(UselessMiddleware::class),
             new Reference($factoryChildMiddlewareId),
             new Reference($factoryWithDefaultChildMiddlewareId),
-            new Reference($childMiddlewareId),
         ), $container->getDefinition($fooBusId)->getArgument(0));
         $this->assertFalse($container->hasParameter($middlewareParameter));
     }

Tests/DependencyInjection/MessengerPassTest.php

@@ -25,14 +25,10 @@ public function testItLocatesHandlerUsingTheMessageClass()
         $this->assertSame($handler, $resolvedHandler);
     }
 
-    /**
-     * @expectedException \Symfony\Component\Messenger\Exception\NoHandlerForMessageException
-     * @expectedExceptionMessage No handler for message "Symfony\Component\Messenger\Tests\Fixtures\DummyMessage"
-     */
-    public function testThrowsNoHandlerException()
+    public function testNoHandlersReturnsNull()
     {
         $locator = new ContainerHandlerLocator(new Container());
-        $locator->getHandler(new Envelope(new DummyMessage('Hey')));
+        $this->assertNull($locator->getHandler(new Envelope(new DummyMessage('Hey'))));
     }
 
     public function testGetHandlerViaInterface()

Tests/Handler/Locator/ContainerHandlerLocatorTest.php

@@ -37,4 +37,22 @@ public function testItCallsTheHandlerAndNextMiddleware()
 
         $middleware->handle($envelope, $next);
     }
+
+    /**
+     * @expectedException \Symfony\Component\Messenger\Exception\NoHandlerForMessageException
+     * @expectedExceptionMessage No handler for message "Symfony\Component\Messenger\Tests\Fixtures\DummyMessage"
+     */
+    public function testThrowsNoHandlerException()
+    {
+        $middleware = new HandleMessageMiddleware(new HandlerLocator(array()));
+
+        $middleware->handle(new Envelope(new DummyMessage('Hey')), function () {});
+    }
+
+    public function testAllowNoHandlers()
+    {
+        $middleware = new HandleMessageMiddleware(new HandlerLocator(array()), true);
+
+        $this->assertNull($middleware->handle(new Envelope(new DummyMessage('Hey')), function () {}));
+    }
 }