Why is my call to get Twitter user timeline returning "401 Unauthorized."? [duplicate]

Question

I have the following code shamelessly taken from dev.twitter to get the time line of a specific user:

string endpoint = "https://api.twitter.com/1.1/statuses/user_timeline.json";

string user_name = ".....";

string ConsumerKey = "....";
string ConsumerSecret = "........";
string Token = ".......";
string TokenSecret = "........";

// oauth application keys
var oauth_token = Token;
var oauth_token_secret = TokenSecret;
var oauth_consumer_key = ConsumerKey;
var oauth_consumer_secret = ConsumerSecret;

// oauth implementation details
var oauth_version = "1.0";
var oauth_signature_method = "HMAC-SHA1";

// unique request details
var oauth_nonce = Convert.ToBase64String(new ASCIIEncoding().GetBytes(DateTime.Now.Ticks.ToString()));
var timeSpan = DateTime.UtcNow
    - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
var oauth_timestamp = Convert.ToInt64(timeSpan.TotalSeconds).ToString();

var baseFormat = "oauth_consumer_key={0}&oauth_nonce={1}&oauth_signature_method={2}" +
                "&oauth_timestamp={3}&oauth_token={4}&oauth_version={5}&screen_name={6}";

var baseString = string.Format(baseFormat,
                            oauth_consumer_key,
                            oauth_nonce,
                            oauth_signature_method,
                            oauth_timestamp,
                            oauth_token,
                            oauth_version,
                            user_name
                            );

//&include_rts=true &exclude_replies=false

baseString = string.Concat("GET&", Uri.EscapeDataString(endpoint), "&", Uri.EscapeDataString(baseString));

var compositeKey = string.Concat(Uri.EscapeDataString(oauth_consumer_secret),
                        "&", Uri.EscapeDataString(oauth_token_secret));

string oauth_signature;
using (HMACSHA1 hasher = new HMACSHA1(ASCIIEncoding.ASCII.GetBytes(compositeKey)))
{
    oauth_signature = Convert.ToBase64String(hasher.ComputeHash(ASCIIEncoding.ASCII.GetBytes(baseString)));
}

string headerFormat = "OAuth oauth_nonce=\"{0}\", oauth_signature_method=\"{1}\", " +
                      "oauth_timestamp=\"{2}\", oauth_consumer_key=\"{3}\", " +
                      "oauth_token=\"{4}\", oauth_signature=\"{5}\", " +
                      "oauth_version=\"{6}\",screen_name=\"{7}\"";
var authHeader = string.Format(headerFormat,
                               Uri.EscapeDataString(oauth_nonce),
                               Uri.EscapeDataString(oauth_signature_method),
                               Uri.EscapeDataString(oauth_timestamp),
                               Uri.EscapeDataString(oauth_consumer_key),
                               Uri.EscapeDataString(oauth_token),
                               Uri.EscapeDataString(oauth_signature),
                               Uri.EscapeDataString(oauth_version),
                               Uri.EscapeDataString(user_name)
            );

// make the request
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(endpoint);
request.Headers.Add("Authorization", authHeader);
request.Method = "GET";
request.ContentType = "application/x-www-form-urlencoded";
var response = (HttpWebResponse)request.GetResponse();
var reader = new StreamReader(response.GetResponseStream());
var objText = reader.ReadToEnd();

However, I'm getting a 401, Unauthorized error on this line:

var response = (HttpWebResponse)request.GetResponse();

(as indeed are the last couple of posters on that Twitter developer thread).

Is there any way I can quickly check that my various tokens, keys and secrets are valid and should return the data I'm looking for?

Answer 1

I have created a test console application on GitHub that does this here:

Authenticate and request a user's timeline with Twitter API 1.1 oAuth

Please see my question and answer, markup if you find it of use.