Bus restricting with Interfaces

Proposed more flexible way to restrict handlers with buses - use interfaces for this.

Author: CvekCoding

messenger/multiple_buses.rst

@@ -161,19 +161,13 @@ the correct tag:
         # config/services.yaml
 
         # put this after the "App\" line that registers all your services
-        command_handlers:
-            namespace: App\MessageHandler\
-            resource: '%kernel.project_dir%/src/MessageHandler/*CommandHandler.php'
-            autoconfigure: false
-            tags:
-                - { name: messenger.message_handler, bus: command.bus }
-
-        query_handlers:
-            namespace: App\MessageHandler\
-            resource: '%kernel.project_dir%/src/MessageHandler/*QueryHandler.php'
-            autoconfigure: false
-            tags:
-                - { name: messenger.message_handler, bus: query.bus }
+        _instanceof:
+            App\MessageHandler\CommandHandlerInterface:
+                tags: 
+                    - { name: messenger.message_handler, bus: command.bus }
+            App\MessageHandler\QueryHandlerInterface:
+                tags:
+                    - { name: messenger.message_handler, bus: query.bus }
 
     .. code-block:: xml
 
@@ -186,31 +180,40 @@ the correct tag:
 
             <services>
                 <!-- command handlers -->
-                <prototype namespace="App\MessageHandler\" resource="%kernel.project_dir%/src/MessageHandler/*CommandHandler.php" autoconfigure="false">
-                    <tag name="messenger.message_handler" bus="command.bus"/>
-                </service>
+                <instanceof id="App\MessageHandler\CommandHandlerInterface" autowire="true">
+                    <tag name="messenger.message_handler", bus="command.bus"/>
+                </instanceof>
                 <!-- query handlers -->
-                <prototype namespace="App\MessageHandler\" resource="%kernel.project_dir%/src/MessageHandler/*QueryHandler.php" autoconfigure="false">
-                    <tag name="messenger.message_handler" bus="query.bus"/>
-                </service>
+                <instanceof id="App\MessageHandler\QueryHandlerInterface" autowire="true">
+                    <tag name="messenger.message_handler", bus="query.bus"/>
+                </instanceof>
             </services>
         </container>
 
     .. code-block:: php
 
         // config/services.php
+        namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 
-        // Command handlers
-        $container->services()
-            ->load('App\MessageHandler\\', '%kernel.project_dir%/src/MessageHandler/*CommandHandler.php')
-            ->autoconfigure(false)
-            ->tag('messenger.message_handler', ['bus' => 'command.bus']);
+        use App\MessageHandler\CommandHandlerInterface;
+        use App\MessageHandler\QueryHandlerInterface;
 
-        // Query handlers
-        $container->services()
-            ->load('App\MessageHandler\\', '%kernel.project_dir%/src/MessageHandler/*QueryHandler.php')
-            ->autoconfigure(false)
-            ->tag('messenger.message_handler', ['bus' => 'query.bus']);
+        return function(ContainerConfigurator $configurator) {
+            $services = $configurator->services();
+
+            // Command handlers
+            $services
+                ->instanceof(CommandHandlerInterface::class)
+                    ->tag('messenger.message_handler', ['bus' => 'command.bus']);
+                    
+            // Query handlers
+            $services
+                ->instanceof(QueryHandlerInterface::class)
+                    ->tag('messenger.message_handler', ['bus' => 'query.bus']);
+
+        };
+
+From now any handler implementing ``CommandHandlerInterface`` will be automatically restricted to ``command.bus`` bus. The same is true for ``query.bus`` bus - just implement ``QueryHandlerInterface`` interface.
 
 Debugging the Buses
 -------------------