Twitter POST problems using api 1.1

Question

We\'ve just changed to Twitter api 1.1, and now Tweeting doesn\'t work & returns an error \"The remote server returned an error: (400) Bad Request.\" Researching on SO

Answer 1

Finally found the solution, as usual with most of these things, it was pretty simple. Code below -

    public void Tweet(Action response, string message)
    {
        StringBuilder sb = new StringBuilder();
        sb.AppendFormat ("status={0}", PercentEncode(message));

        string content = sb.ToString();


        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(_postUrl);

        request.Headers.Add("Authorization", AuthorizeRequest(_accessToken, _accessTokenSecret, "POST", new Uri(_postUrl), content));
        request.ContentType = "application/x-www-form-urlencoded";
        request.ServicePoint.Expect100Continue = false;
        request.Method = "POST";


        try
        {
            try
            {
                using (Stream stream = request.GetRequestStream())
                {
                    Byte[] streamContent = Encoding.UTF8.GetBytes("status=" + PercentEncode(message));
                    stream.Write(streamContent, 0, streamContent.Length);
                }


                HttpWebResponse webResponse = (HttpWebResponse)request.GetResponse();

                string contents = "";
                using (Stream stream = webResponse.GetResponseStream())
                    using (StreamReader reader = new StreamReader(stream))
                    {
                        contents = reader.ReadToEnd();
                    }

                Console.WriteLine("Twitter response: " + contents);

                response(DefaultSuccessMessage());

            }
            catch (WebException e)
            {
                Log.Info("TwitterService->Tweet web error: " + e.Message);
                response(DefaultErrorMessage());
            }
            catch (Exception e)
            {
                // Can happen if we had already favorited this status
                Log.Info("TwitterService->Tweet error: " + e.Message);
                response(DefaultErrorMessage());
            }
        }
        catch (WebException e)
        {
            Log.Info("TwitterService->Tweet web error 2: " + e.Message);
            response(DefaultErrorMessage());
        }
        catch (Exception e)
        {
            Log.Info("TwitterService->Tweet error 2: " + e.Message);
            response(DefaultErrorMessage());
        }
    }


    private string AuthorizeRequest(string oauthToken, string oauthTokenSecret, string method, Uri uri, string data)
    {
        string oauthNonce = Convert.ToBase64String(new ASCIIEncoding().GetBytes(DateTime.Now.Ticks.ToString()));

        var headers = new Dictionary()
        {
            { "oauth_consumer_key", _oAuthConfig.ConsumerKey },
            { "oauth_nonce", oauthNonce },
            { "oauth_signature_method", "HMAC-SHA1" },
            { "oauth_timestamp", MakeTimestamp() },
            { "oauth_token", oauthToken },
            { "oauth_verifier", PercentEncode(_authorizationVerifier) },
            { "oauth_version", "1.0A" }
        };
        var signatureHeaders = new Dictionary(headers);

        // Add the data and URL query string to the copy of the headers for computing the signature
        if (data != null && data != "")
        {
            var parsed = HttpUtility.ParseQueryString(data);
            foreach (string k in parsed.Keys)
            {
                signatureHeaders.Add(k, PercentEncode(parsed [k]));
            }
        }

        var nvc = HttpUtility.ParseQueryString(uri.Query);
        foreach (string key in nvc)
        {
            if (key != null)
                signatureHeaders.Add(key, PercentEncode(nvc [key]));
        }

        string signature = MakeSignature (method, uri.GetLeftPart(UriPartial.Path), signatureHeaders);
        string compositeSigningKey = MakeSigningKey(_oAuthConfig.ConsumerSecret, oauthTokenSecret);
        string oauth_signature = MakeOAuthSignature(compositeSigningKey, signature);

        headers.Add ("oauth_signature", PercentEncode(oauth_signature));


        return HeadersToOAuth(headers);
    }


    private static string PercentEncode (string s)
    {
        var sb = new StringBuilder ();

        foreach (byte c in Encoding.UTF8.GetBytes (s))
        {
            if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '-' || c == '_' || c == '.' || c == '~')
                sb.Append ((char) c);
            else
            {
                sb.AppendFormat ("%{0:X2}", c);
            }
        }
        return sb.ToString ();
    }


    private static string MakeTimestamp ()
    {
        return ((long) (DateTime.UtcNow - _unixBaseTime).TotalSeconds).ToString ();
    }

    private static string MakeSignature (string method, string base_uri, Dictionary headers)
    {
        var items = from k in headers.Keys orderby k 
            select k + "%3D" + PercentEncode (headers [k]);

        return method + "&" + PercentEncode (base_uri) + "&" + 
            string.Join ("%26", items.ToArray ());
    }

    private static string MakeSigningKey (string consumerSecret, string oauthTokenSecret)
    {
        return PercentEncode (consumerSecret) + "&" + (oauthTokenSecret != null ? PercentEncode (oauthTokenSecret) : "");
    }

    private static string MakeOAuthSignature (string compositeSigningKey, string signatureBase)
    {
        var sha1 = new HMACSHA1 (Encoding.UTF8.GetBytes (compositeSigningKey));

        return Convert.ToBase64String (sha1.ComputeHash (Encoding.UTF8.GetBytes (signatureBase)));
    }

    private static string HeadersToOAuth (Dictionary headers)
    {
        return "OAuth " + String.Join (",", (from x in headers.Keys select String.Format ("{0}=\"{1}\"", x, headers [x])).ToArray ());
    }

With Twitter api 1.0, I used a WebClient to post, that doesn't work with api 1.1, and it seems that the reason for this is that you can't set the ContentType or the ServicePoint.Expect100Continue properties - without these set as I've set them, the request is sent back as (401) unauthorized. Nothing to do with encoding problems in the end.

Thanks to others for the various helper methods.