c# – HttpWebRequests在Authorization标头中发送无参数URI

如果将来有人遇到此问题,您可以调用解决方法,如：

var resultText = DigestAuthFixer.GrabResponse("/dir/index.html");

DigestAuthFixer类的代码：

public static class DigestAuthFixer
{
    private static string _host = "http://localhost";
    private static string _user = "Mufasa";
    private static string _password = "Circle Of Life";
    private static string _realm;
    private static string _nonce;
    private static string _qop;
    private static string _cnonce;
    private static DateTime _cnonceDate;
    private static int _nc;

    private static string CalculateMd5Hash(
        string input)
    {
        var inputBytes = Encoding.ASCII.GetBytes(input);
        var hash = MD5.Create().ComputeHash(inputBytes);
        var sb = new StringBuilder();
        foreach (var b in hash)
            sb.Append(b.ToString("x2"));
        return sb.ToString();
    }

    private static string GrabHeaderVar(
        string varName,string header)
    {
        var regHeader = new Regex(string.Format(@"{0}=""([^""]*)""",varName));
        var matchHeader = regHeader.Match(header);
        if (matchHeader.Success)
            return matchHeader.Groups[1].Value;
        throw new ApplicationException(string.Format("Header {0} not found",varName));
    }

    // http://en.wikipedia.org/wiki/Digest_access_authentication
    private static string GetDigestHeader(
        string dir)
    {
        _nc = _nc + 1;

        var ha1 = CalculateMd5Hash(string.Format("{0}:{1}:{2}",_user,_realm,_password));
        var ha2 = CalculateMd5Hash(string.Format("{0}:{1}","GET",dir));
        var digestResponse =
            CalculateMd5Hash(string.Format("{0}:{1}:{2:00000000}:{3}:{4}:{5}",ha1,_nonce,_nc,_cnonce,_qop,ha2));

        return string.Format("Digest username="{0}",realm="{1}",nonce="{2}",uri="{3}"," +
            "algorithm=MD5,response="{4}",qop={5},nc={6:00000000},cnonce="{7}"",dir,digestResponse,_cnonce);
    }

    public static string GrabResponse(
        string dir)
    {
        var url = _host + dir;
        var uri = new Uri(url);

        var request = (HttpWebRequest)WebRequest.Create(uri);

        // If we've got a recent Auth header,re-use it!
        if (!string.IsNullOrEmpty(_cnonce) &&
            DateTime.Now.Subtract(_cnonceDate).TotalHours < 1.0)
        {
            request.Headers.Add("Authorization",GetDigestHeader(dir));
        }

        HttpWebResponse response;
        try
        {
            response = (HttpWebResponse)request.GetResponse();
        }
        catch (WebException ex)
        {
            // Try to fix a 401 exception by adding a Authorization header
            if (ex.Response == null || ((HttpWebResponse)ex.Response).StatusCode != HttpStatusCode.Unauthorized)
                throw;

            var wwwAuthenticateHeader = ex.Response.Headers["WWW-Authenticate"];
            _realm = GrabHeaderVar("realm",wwwAuthenticateHeader);
            _nonce = GrabHeaderVar("nonce",wwwAuthenticateHeader);
            _qop = GrabHeaderVar("qop",wwwAuthenticateHeader);

            _nc = 0;
            _cnonce = new Random().Next(123400,9999999).ToString();
            _cnonceDate = DateTime.Now;

            var request2 = (HttpWebRequest)WebRequest.Create(uri);
            request2.Headers.Add("Authorization",GetDigestHeader(dir));
            response = (HttpWebResponse)request2.GetResponse();
        }
        var reader = new StreamReader(response.GetResponseStream());
        return reader.ReadToEnd();
    }
}