Move everything around as needed to get things setup for the client API

app/Http/Controllers/Api/Client/ClientApiController.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace Pterodactyl\Http\Controllers\Api\Application;
+
+use Illuminate\Container\Container;
+use Pterodactyl\Exceptions\Transformer\InvalidTransformerLevelException;
+
+abstract class ClientApiController extends ApplicationApiController
+{
+    /**
+     * Return an instance of an application transformer.
+     *
+     * @param string $abstract
+     * @return \Pterodactyl\Transformers\Api\Client\BaseClientTransformer
+     *
+     * @throws \Pterodactyl\Exceptions\Transformer\InvalidTransformerLevelException
+     */
+    public function getTransformer(string $abstract)
+    {
+        /** @var \Pterodactyl\Transformers\Api\Client\BaseClientTransformer $transformer */
+        $transformer = Container::getInstance()->make($abstract);
+        $transformer->setKey($this->request->attributes->get('api_key'));
+
+        if (! $transformer instanceof self) {
+            throw new InvalidTransformerLevelException('Calls to ' . __METHOD__ . ' must return a transformer that is an instance of ' . __CLASS__);
+        }
+
+        return $transformer;
+    }
+}

app/Http/Controllers/Api/Client/ClientController.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace Pterodactyl\Http\Controllers\Api\Client;
+
+use Pterodactyl\Http\Controllers\Api\Application\ClientApiController;
+
+class ClientController extends ClientApiController
+{
+}