How to get access token for google oauth?

Question

I am using C# (ASP.NET). I want to use Google OAuth for accessing the user profile detail in my app. I successfully got the authorization code but having a problem in getting th

Answer 1

public string ReceiveTokenGmail(string code, string GoogleWebAppClientID, string GoogleWebAppClientSecret, string RedirectUrl)
{
    string postString = "code=" + code + "&client_id=" + GoogleWebAppClientID + @"&client_secret=" + GoogleWebAppClientSecret  + "&redirect_uri=" + RedirectUrl;

    string url = "https://accounts.google.com/o/oauth2/token";

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url.ToString());
    request.Method = "POST";
    request.ContentType = "application/x-www-form-urlencoded";

    UTF8Encoding utfenc = new UTF8Encoding();
    byte[] bytes = utfenc.GetBytes(postString);
    Stream os = null;
    try
    {
        request.ContentLength = bytes.Length;
        os = request.GetRequestStream();
        os.Write(bytes, 0, bytes.Length);
    }
    catch
    { }
    string result = "";

    HttpWebResponse webResponse = (HttpWebResponse)request.GetResponse();
    Stream responseStream = webResponse.GetResponseStream();
    StreamReader responseStreamReader = new StreamReader(responseStream);
    result = responseStreamReader.ReadToEnd();

    return result;
}