Add authentication configuration and allowed methods logic

src/Socialbox/Classes/StandardMethods/GetAllowedMethods.php

@@ -0,0 +1,38 @@
+<?php
+
+    namespace Socialbox\Classes\StandardMethods;
+
+    use Socialbox\Abstracts\Method;
+    use Socialbox\Enums\StandardError;
+    use Socialbox\Enums\StandardMethods;
+    use Socialbox\Exceptions\DatabaseOperationException;
+    use Socialbox\Exceptions\StandardException;
+    use Socialbox\Interfaces\SerializableInterface;
+    use Socialbox\Objects\ClientRequest;
+    use Socialbox\Objects\RpcRequest;
+
+    class GetAllowedMethods extends Method
+    {
+
+        /**
+         * @inheritDoc
+         */
+        public static function execute(ClientRequest $request, RpcRequest $rpcRequest): ?SerializableInterface
+        {
+            $allowedMethods = [];
+
+            try
+            {
+                foreach(StandardMethods::getAllowedMethods($request) as $method)
+                {
+                    $allowedMethods[] = $method->value;
+                }
+            }
+            catch(DatabaseOperationException $e)
+            {
+                throw new StandardException('Failed to retrieve allowed methods due to an internal exception', StandardError::INTERNAL_SERVER_ERROR, $e);
+            }
+
+            return $rpcRequest->produceResponse($allowedMethods);
+        }
+    }