Multiple fixes

config/services.yaml

@@ -119,6 +119,9 @@ services:
     Cheeper\Chapter7\DomainModel\Follow\FollowRepository:
         class: 'Cheeper\Chapter7\Infrastructure\DomainModel\Follow\DoctrineOrmFollowRepository'
 
+    Cheeper\Chapter7\DomainModel\Notifier\Notifier:
+        class: 'Cheeper\Chapter7\Infrastructure\DomainModel\Notifier\NullNotifier'
+
     Cheeper\Chapter7\Application\CommandBus:
         class: 'Cheeper\Chapter7\Infrastructure\Application\SymfonyCommandBus'
 

src/Cheeper/Chapter7/Application/Author/Event/NewAuthorSigned/WhenNewAuthorSignedThenWelcomeAuthorEventHandler.php

@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace Cheeper\Chapter7\Application\Author\Event\AuthorFollowed;
+namespace Cheeper\Chapter7\Application\Author\Event\NewAuthorSigned;
 
 use Cheeper\Chapter7\Application\Author\Command\WelcomeCommand;
 use Cheeper\Chapter7\Application\CommandBus;

src/Cheeper/Chapter7/Infrastructure/Application/SymfonyCommandBus.php

@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cheeper\Chapter7\Infrastructure\Application;
+
+use Cheeper\Chapter7\Application\CommandBus;
+use function Functional\first;
+use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\Exception\HandlerFailedException;
+use Symfony\Component\Messenger\MessageBusInterface;
+
+// snippet symfony-command-bus
+final class SymfonyCommandBus implements CommandBus
+{
+    public function __construct(
+        private MessageBusInterface $commandBus
+    ) {
+    }
+
+    public function handle(object $command): Envelope
+    {
+        try {
+            $envelope = $this->commandBus->dispatch($command);
+        } catch (HandlerFailedException $exception) {
+            throw first($exception->getNestedExceptions());
+        }
+
+        return $envelope;
+    }
+}
+//end-snippet

src/Cheeper/Chapter7/Infrastructure/DomainModel/Notifier/NullNotifier.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cheeper\Chapter7\Infrastructure\DomainModel\Notifier;
+
+use Cheeper\Chapter7\DomainModel\Author\Author;
+
+final class NullNotifier
+{
+    public function notify(Author $author): void
+    {
+        // Send email or do whatever
+    }
+}