How to force WebRequest to send Authorization header during POST

Question

When using WebRequest to send a POST, the Authorization header is not sent with the request even though I have manually set the header and set PreAuthenticate to true, eg:

webRequest.Headers["Authorization"] = "OAuth oauth_consumer_key=bFPD...";
webRequest.PreAuthenticate = true;

Using Fiddler I can see that the Authorization header is not sent. The target site (Twitter) returns a 400 (Bad request) rather than a 401 (Not authorized) which is therefore the incorrect challenge required for WebRequest to send the Authorization data. For information, the returned content is:

{"errors":[{"message":"Bad Authentication data","code":215}]}

So, how do I get around this? How can I force WebRequest to send the Authorization with initial request? Note that the authorization data is not Basic Authentication, rather it is an OAuth string.

Thanks

Answer 1

Here's my solution. The value is in variable json.

var myUri = new Uri(fullpath);
var myWebRequest = WebRequest.Create(myUri);
var myHttpWebRequest = (HttpWebRequest)myWebRequest;
myHttpWebRequest.PreAuthenticate = true;
myHttpWebRequest.Headers.Add("Authorization", "Bearer " + AccessToken);
myHttpWebRequest.Accept = "application/json";

var myWebResponse = myWebRequest.GetResponse();
var responseStream = myWebResponse.GetResponseStream();
if (responseStream == null) return null;

var myStreamReader = new StreamReader(responseStream, Encoding.Default);
var json = myStreamReader.ReadToEnd();

responseStream.Close();
myWebResponse.Close();

Answer 2

This drove me bonkers, but eventually found the answer in Adding Headers and Post data in RESTfull/HTTP Request in C#.

The solution for me was adding the Authorization Header BEFORE writing the request stream.

Hope this helps.

Answer 3

Try this, but there should be no space between the authorization headers.

var authHeader = "OAuth  oauth_consumer_key=bFPD...";
webRequest.Headers.Add("Authorization", authHeader);