Making HTTP requests to onprem SharePoint Server (Project Server)

Question

I have existing code that makes plain HTTP requests against the REST API's of SharePoint Online (Project Online):

protected object MakeRESTCall(string restRelativeUrl, RestResultType resultType)
{
    var requestUri = GetAbsoluteRESTUri(restRelativeUrl);
    int timeout = 300000; // 300 seconds
    var restRequest = (HttpWebRequest)WebRequest.Create(requestUri);
    restRequest.Method = "GET";
    restRequest.Timeout = timeout;
    restRequest.ReadWriteTimeout = timeout;
    if (resultType == RestResultType.Json)
    {
        restRequest.Accept = "application/json;odata=verbose";
        restRequest.ContentType = "application/json";
    }
    restRequest.Headers.Add("X-FORMS_BASED_AUTH_ACCEPTED", "f");

    var authCookie = GetAuthCookie();
    var cookies = new CookieContainer();
    cookies.SetCookies(new Uri(Settings.ConnectionInfo.Url), authCookie);
    restRequest.CookieContainer = cookies;

    using (var response = (HttpWebResponse)restRequest.GetResponse())
    {
        if (response.StatusCode != HttpStatusCode.OK)
        {
            throw new Exception($"Server error (HTTP {response.StatusCode}: {response.StatusDescription}).");
        }

        var encoding = response.CharacterSet == string.Empty ? Encoding.UTF8 : Encoding.GetEncoding(response.CharacterSet);

        using (var stream = response.GetResponseStream())
        using (var reader = new StreamReader(stream, encoding))
        {
            var responseString = reader.ReadToEnd();
            object result = responseString;

            if (resultType == RestResultType.Json)
            {
                result = JObject.Parse(responseString);
            }
            return result;
        }
    }
}

The GetAuthCookie() method looks like this:

public string GetAuthCookie()
{
    var creds = GetCredentials();
    return creds.GetAuthenticationCookie(<my url>);
}

The GetCredentials() method looks like this:

private ICredentials GetCredentials()
{
    var securePassword = new SecureString();
    foreach (var c in <password>)
    {
        securePassword.AppendChar(c);
    }

    if (IsOnline)
    {
        return new SharePointOnlineCredentials(<login>, securePassword);
    }
    return new NetworkCredential(<login>, securePassword);
}

The original code used to work for Project Online and used the SharePointOnlineCredentials class, but having to support both Project Online and Project Server, I have changed the GetCredentials()-method to return an ICredentials type instead of the original SharePointOnlineCredentials type.

And the ICredentials-interface does not contain a .GetAuthenticationCookie()-method.

The question is:

How do I rewrite my MakeRESTCall method to work for Project Server as well?

Thanks :-)

Answer 1

Apparently a cookie is not needed for NTLM-authentication, so removing those 4 lines handling the cookie magic, made everything work.