common\services\PostService::parseUsername PHP Метод

    public static function parseUsername($content)
    {
        preg_match_all('/@(\\S{4,255}) /', $content, $matches);
        if (empty($matches[1])) {
            return [];
        }
        $existUserRows = User::find()->where(['username' => $matches[1]])->select('id,username')->asArray()->all();
        return ArrayHelper::map($existUserRows, 'id', 'username') ?: [];
    }