yii\mongodb\file\Upload::addFile PHP Метод

    public function addFile($filename)
    {
        if ($this->filename === null) {
            $this->filename = basename($filename);
        }
        $stream = fopen($filename, 'r+');
        if ($stream === false) {
            throw new InvalidParamException("Unable to read file '{$filename}'");
        }
        return $this->addStream($stream);
    }