内容处置 - 在邮件 header 中发现无效字符：'['

Question

I want to get filename from the url below. When parsing Content-Disposition header to extract the filename it throws an error System.FormatException: An invalid character was found in the mail header: '['. .The value of the header is like below. I don't want to replace these characters because the filename will be changed if I do. How can I fix it?

Content-Disposition: attachment; filename*=UTF-8''[Saglamindir.net] Internet Download Manager.rar
Url: https://www17.zippyshare.com/d/qS76ZdES/29289/%5bSaglamindir.net%5d%20Internet%20Download%20Manager.rar

My Code:

var cdHeader = response.Headers["Content-Disposition"];
if (!string.IsNullOrEmpty(cdHeader))
{
    var properFormat = Encoding.UTF8.GetString(Encoding.GetEncoding(1252).GetBytes(cdHeader));
    properFormat = HttpUtility.UrlDecode(properFormat);
    var disp = new ContentDisposition(properFormat);
    var temp = disp.FileName;
    return temp.ReplaceInvalidChars();
}

Answer 1

You can't use unescaped "[" or "]" here (they need percent-encoding). The relevant specs are RFC 6266 (Content-Disposition) and RFC 8187.