<?phpusemystic\forum\orm\Topic;$formId="addpost";$topicId=$_GET["topic"]??call_user_func(function(){http_response_code(400);msg_error(__("Missing topic id"));exit;});$topic=newTopic();$topic->id=$topicId;if(!$db->fetch($topic)){http_response_code(404);msg_error(__("No topic exists with this id"));exit;}