private function saveCache(array $data)
    {
        $this->cache = $data; // Save new data in object to avoid useless I/O access
        $opt = '';
        if (ForumEnv::get('FEATHER_DEBUG')) {
            $opt = JSON_PRETTY_PRINT;
        }
        return file_put_contents($this->getCacheFile(), json_encode($data, $opt));
    }