Connecting to Twitter - RestSharp OAuth2

Question

I am attempting to connect to the Twitter API with these instructions

https://dev.twitter.com/docs/auth/application-only-auth

Here is my code:

var baseUrl = "http://api.twitter.com/";
var client = new RestClient(baseUrl);                     
var request = new RestRequest("/oauth2/token", Method.POST);

var concat = ConfigurationManager.AppSettings["TwitterConsumerKey"] + ":" +
     ConfigurationManager.AppSettings["TwitterConsumerSecret"];

string encodeTo64 = concat.EncodeTo64();

request.AddHeader("Authorization", "Basic " + encodeTo64);
request.AddHeader("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
request.AddBody("grant_type=client_credentials");
IRestResponse restResponse = client.Execute(request);

EncodeTo64

static public string EncodeTo64(this string toEncode)
    {
        byte[] toEncodeAsBytes
              = System.Text.ASCIIEncoding.ASCII.GetBytes(toEncode);
        string returnValue
              = System.Convert.ToBase64String(toEncodeAsBytes);
        return returnValue;
    }

Response.Content is the following

"{\"errors\":[{\"code\":170,\"label\":\"forbidden_missing_parameter\",\"message\":\"Missing required parameter: grant_type\"}]}"

Is this part wrong?

request.AddBody("grant_type=client_credentials");

I have verified that my credentials are correct (I got that error before, but resolved it, so it should be OK).

Answer 1

The instructions on the Twitter page confused me. "The body of the request must be grant_type=client_credentials."

As for Restsharp, it's not AddBody, but AddParameter.

So:

request.AddParameter("grant_type", "client_credentials");