Add Authenticate method to handle external peer authentication

src/Socialbox/Classes/StandardMethods/Authenticate.php

@@ -0,0 +1,45 @@
+<?php
+
+    namespace Socialbox\Classes\StandardMethods;
+
+    use Exception;
+    use Socialbox\Abstracts\Method;
+    use Socialbox\Enums\Flags\SessionFlags;
+    use Socialbox\Enums\StandardError;
+    use Socialbox\Exceptions\StandardException;
+    use Socialbox\Interfaces\SerializableInterface;
+    use Socialbox\Managers\SessionManager;
+    use Socialbox\Objects\ClientRequest;
+    use Socialbox\Objects\RpcRequest;
+
+    class Authenticate extends Method
+    {
+        /**
+         * @inheritDoc
+         */
+        public static function execute(ClientRequest $request, RpcRequest $rpcRequest): ?SerializableInterface
+        {
+            try
+            {
+                if(!$request->getPeer()->isExternal())
+                {
+                    return $rpcRequest->produceError(StandardError::FORBIDDEN, 'Only external peers can authenticate');
+                }
+
+                if($request->getSession()->isAuthenticated())
+                {
+                    return $rpcRequest->produceError(StandardError::FORBIDDEN, 'Peer is already authenticated');
+                }
+
+                SessionManager::removeFlags($request->getPeer()->getUuid(), [SessionFlags::AUTHENTICATION_REQUIRED]);
+                SessionManager::setAuthenticated($request->getPeer()->getUuid(), true);
+            }
+            catch(Exception $e)
+            {
+                throw new StandardException('An error occurred while authenticating the peer', StandardError::INTERNAL_SERVER_ERROR, $e);
+            }
+
+
+            return $rpcRequest->produceResponse(true);
+        }
+    }