How to follow user on Twitter pragmatically

Question

I'm doing some twitter experiment and finished all GET request from Twitter API reference, but for some reason I can't send a post request.

I'm trying to follow user on twitter pragmatically but for some reason I only got a forbidden error instead of JSON reponse. Am I doing something wrong on this?

Twitter API : POST friendship/create

The remote server returned an error: (403) Forbidden.

Here is my code;

try {
    var followFormat = "https://api.twitter.com/1.1/friendships/create.json?user_id={0}&follow=true";
    var followUrl = String.Format(followFormat, id);
    HttpWebRequest followRequest = (HttpWebRequest) WebRequest.Create(followUrl);
    var followHeaderFormat = "{0} {1}";
    followRequest.Headers.Add("Authorization", String.Format(followHeaderFormat, twitAuthResponse.token_type, twitAuthResponse.access_token));
    followRequest.Method = "POST";
    followRequest.ContentType = "application/x-www-form-urlencoded;charset=UTF-8";
    followRequest.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
    using(Stream stream = followRequest.GetRequestStream()) {
        byte[] content = Encoding.ASCII.GetBytes(postBody);
        stream.Write(content, 0, content.Length);
    }
    followRequest.Headers.Add("Accept-Encoding", "gzip");
    WebResponse followResponse = followRequest.GetResponse(); // Error Here
    User userResponse;
    using(followResponse) {
        using(var reader = new StreamReader(followResponse.GetResponseStream())) {
            JavaScriptSerializer js = new JavaScriptSerializer();
            var objectText = reader.ReadToEnd();
            userResponse = JsonConvert.DeserializeObject < User > (objectText);
        }
    }
    Console.WriteLine("Success: You followed {0}", userResponse.ScreenName);
} catch(Exception e) {
    Console.WriteLine("Failed To Follow: {0}", e.Message);
}

For authentication, I'm sure my credential is working because I used it on Twitter GET.

Answer 1

According to the API documentation, I suspect that you're already following the user hence the 403:

If the user is already friends with the user a HTTP 403 may be returned, though for performance reasons this method may also return a HTTP 200 OK message even if the follow relationship already exists.