NTLM over HTTP: Any C# client implementation?

Question

I need to programmatically download a file from a SharePoint server.

When I download the file with Firefox it looks like a single request, but Httpfox shows that the HTTPS conversation is actually 4 requests:

REQ1: GET https://mycorp.raxsp.com/_windows/default.aspx?ReturnUrl=/personal/mycorp_user1/_vti_bin/cmis/rest?getRepositories
RESP1: 401 Unauthorized, WWW-Authenticate NTLM

REQ2: Authorization NTLM TlRMTVNTUAABAAAAB4IIAAAAAAAAAAAAAAAAAAAAAAA=
RESP2: 401, WWW-Authenticate    NTLM TlRMTVNTUAACAAAACgAKADgAAAAFgokC+[...]

REQ3: Authorization NTLM TlRMTVNTUAADAAAAGAAYAIAAAAAYA[...]
RESP3: 302 Found, Set-Cookie FedAuth=77u/PD94bW[...], Location /personal/mycorp_user1/_vti_bin/cmis/rest?getRepositories

REQ4: GET /personal/mycorp_user1/_vti_bin/cmis/rest?getRepositories
RESP4: 200 OK, <download begins>

I tried downloading the file with a simple HttpWebRequest with user/password, but as expected I just get the error 401. I am considering implementing the whole 4 requests, computing challenges with the NTLM over HTTP authentication algorithm ( spec ), but that sounds very error-prone...

Is there a client-side library or a code snippet that does NTLM over HTTP authentication?
It is for an Open Source project , so must be Open Source, and preferably using HttpWebRequest .
No Kerberos/SSO/domains involved.

Answer 1

We download files from SharePoint all the time with this code using System.Net.WebClient

public static byte [] downloadSharepointFile (string url){
      using (var client = new WebClient { Credentials = new NetworkCredential("username", "password", "domain") })
          {
               client.Headers.Add("Accept: application/json");
               return client.DownloadData(url);
          }
}