Json POST request to the server but server respond (400) Bad Request

Question

I want to use google api for creation of gmail user account. I am sending JSON request to server for getting authorization code but I got these error in httpwebresponse :-

Exception Details: System.Net.WebException: The remote server returned an error: (400) Bad Request

    var request = (HttpWebRequest)WebRequest.Create(@"https://accounts.google.com/o/oauth2/auth");
    request.Method = "POST";
    request.ContentType = "text/json";
    request.KeepAlive = false;

    //request.ContentLength = 0;

    using (StreamWriter streamWriter = new StreamWriter(request.GetRequestStream()))
    {
        string json = "{\"scope\":\"https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.email+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.profile\"," + "\"state\":\"%2Fprofile\"," + "\"redirect_uri\":\"http://gmailcheck.com/response.aspx\"," + "\"response_type\":\"code\"," + "\"client_id\":\"841994137170.apps.googleusercontent.com\"}";

        streamWriter.Write(json);
        // streamWriter.Flush();
        //streamWriter.Close();
    }
        using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
        {
            StreamReader responsereader = new StreamReader(response.GetResponseStream());

            var responsedata = responsereader.ReadToEnd();
            //Session["responseinfo"] = responsereader;

            //testdiv.InnerHtml = responsedata;
        }

}

Answer 1

As soon as you get an exception, you have to read the actual responce from server there should be something helpfull. Like an error description or extended status code...

For Instance:

try
{
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

         ... your code goes here....

}
catch (WebException ex)
        {
        using (WebResponse response = ex.Response)
        {
            var httpResponse = (HttpWebResponse)response;

            using (Stream data = response.GetResponseStream())
            {
                StreamReader sr = new StreamReader(data);
                throw new Exception(sr.ReadToEnd());
            }
        }
    }