[Chapter 7] Clean up unnecessary level

src/Cheeper/Chapter7/Application/Author/Projection/CreateFollowersCounterProjectionHandler.php

@@ -10,6 +10,8 @@ use Redis;
 //snippet create-followers-counter-projection-projector
 final class CreateFollowersCounterProjectionHandler implements CreateFollowersCounterProjectionHandlerInterface
 {
+    public const REDIS_KEY_TEMPLATE = 'author_followers_counter_projection:%s';
+
     public function __construct(
         private Redis $redis
     ) {
@@ -26,7 +28,10 @@ final class CreateFollowersCounterProjectionHandler implements CreateFollowersCo
         ];
 
         $this->redis->set(
-            'author_followers_counter_projection:'.$authorId->toString(),
+            sprintf(
+                self::REDIS_KEY_TEMPLATE,
+                $authorId->toString()
+            ),
             json_encode($result)
         );
     }

src/Cheeper/Chapter7/Application/Cheep/Projection/AddCheepToTimelineProjectionHandler.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Cheeper\Chapter7\Application\Cheep\Projection;
 
+use Cheeper\Chapter7\Application\Author\Projection\CreateFollowersCounterProjectionHandler;
 use Redis;
 
 //snippet add-cheep-to-timeline-projector
@@ -17,13 +18,26 @@ final class AddCheepToTimelineProjectionHandler
     public function __invoke(AddCheepToTimelineProjection $message): void
     {
         $this->redis->lPush(
-            sprintf("timelines_%s", $message->authorId),
-            json_encode([
-                'cheep_id' => $message->cheepId,
-                'cheep_message' => $message->cheepMessage,
-                'cheep_date' => $message->cheepDate,
-            ], JSON_THROW_ON_ERROR)
+            $this->getRedisKey($message),
+            $this->getRedisContent($message)
         );
     }
+
+    private function getRedisKey(AddCheepToTimelineProjection $message): string
+    {
+        return sprintf(
+            CreateFollowersCounterProjectionHandler::REDIS_KEY_TEMPLATE,
+            $message->authorId
+        );
+    }
+
+    private function getRedisContent(AddCheepToTimelineProjection $message): string
+    {
+        return json_encode([
+            'cheep_id' => $message->cheepId,
+            'cheep_message' => $message->cheepMessage,
+            'cheep_date' => $message->cheepDate,
+        ], JSON_THROW_ON_ERROR);
+    }
 }
 //end-snippet