我正在使用现有的产品，我正在尝试解决下载xlsx文件的问题。当我通过文件管理器下载文件时，文件是正确的。但当我通过Yii应用程序下载文件时，文件被损坏。
这是我的代码

public function actionCallLog($hash, $filename)
    {
        var_dump(
            $hash, $filename
        );

        ignore_user_abort(true);
        set_time_limit(0);

        $path = "/var/www/html/uploads/call_log/".$hash.'/';

        $dl_file= basename($filename).'.xlsx';
        if (!file_exists($path.$dl_file)) {
            $dl_file= basename($filename).'.csv';
        }
        $fullPath = $path.$dl_file;

        if ($fd = fopen ($fullPath, "r"))
        {

            $fsize = filesize($fullPath);
            $path_parts = pathinfo($fullPath);
            $ext = strtolower($path_parts["extension"]);
            switch ($ext)
            {
                case "xlsx":
                header('Content-Description: File Transfer');
                header("Content-type: application/xlsx");
                header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\"");
                break;
                case "csv":
                header('Content-Description: File Transfer');
                header("Content-type: application/csv");
                header("Content-Disposition: attachment; filename=\"".$path_parts["basename"]."\"");
                break;
                // add more headers for other content types here
                default;
                header('Content-Description: File Transfer');
                header("Content-type: application/octet-stream");
                header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
                break;
            }
            header("Content-length: $fsize");
            header("Cache-control: private");
            header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
            header('Expires: 0');
            header('Pragma: public');
            while(!feof($fd))
            {
                $buffer = fread($fd, 2048);
                echo $buffer;
            }
        }
        fclose ($fd);
        exit;
    }

有人知道问题出在哪里吗？
谢谢