public ActionResult Handshake(string code)
{
//after authentication, Facebook will redirect to this controller action with a QueryString parameter called "code" (this is Facebook's Session key)
//example uri: http://www.greenfieldzenergy.com/facebook/handshake/?code=2.DQUGad7_kFVGqKTeGUqQTQ__.3600.1273809600-1756053625|dil1rmAUjgbViM_GQutw-PEgPIg.
//this is your Facebook App ID
string clientId = "115893248492995";
//this is your Secret Key
string clientSecret = "9103b1d7d2936f0a9710748674d964e9";
//we have to request an access token from the following Uri
string url = "https://graph.facebook.com/oauth/access_token?client_id={0}&redirect_uri={1}&client_secret={2}&code={3}";
//your redirect uri must be EXACTLY the same Uri that caused the initial authentication handshake
string redirectUri = "http://www.greenfieldzenergy.com:54659/Authentication/handshake/";
//Create a webrequest to perform the request against the Uri
WebRequest request = WebRequest.Create(string.Format(url, clientId, redirectUri, clientSecret, code));
//read out the response as a utf-8 encoding and parse out the access_token
WebResponse response = request.GetResponse();
Stream stream = response.GetResponseStream();
Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
StreamReader streamReader = new StreamReader(stream, encode);
string accessToken = streamReader.ReadToEnd().Replace("access_token=", "");
streamReader.Close();
response.Close();
//set the access token to some session variable so it can be used through out the session
Session["FacebookAccessToken"] = accessToken;
//now that we have an access token, query the Graph Api for the JSON representation of the User
url = "https://graph.facebook.com/me?access_token={0}";
//create the request to https://graph.facebook.com/me
request = WebRequest.Create(string.Format(url, accessToken));
//Get the response
response = request.GetResponse();
//Get the response stream
stream = response.GetResponseStream();
//Take our statically typed representation of the JSON User and deserialize the response stream
//using the DataContractJsonSerializer
DataContractJsonSerializer dataContractJsonSerializer = new DataContractJsonSerializer(typeof(FacebookUser));
FacebookUser user = new FacebookUser();
user = dataContractJsonSerializer.ReadObject(stream) as FacebookUser;
//close the stream
response.Close();
//capture the UserId
Session["FacebookUserId"] = user.id;
//Set the forms authentication auth cookie
FormsAuthentication.SetAuthCookie(user.email, false);
//redirect to home page so that user can start using your application
return RedirectToAction("Index", "Home");
}
