Firstly, the extraData parameter is not passed to facebook. It is for internal use only. See the following link on how this data can be used on your site:
http://blogs.msdn.com/b/pranav_rastogi/archive/2012/08/24/customizing-the-login-ui-when-using-oauth-openid.aspx
Now, to the meat:
In addition to the methods RegisterFacebookClient
, RegisterYahooClient
etc. in OAuthWebSecurity
, there is also a generic method RegisterClient
. This is the method we will be using for this solution.
This idea germinates from the code provided at:
http://mvc4beginner.com/Sample-Code/Facebook-Twitter/MVC-4-oAuth-Facebook-Login-EMail-Problem-Solved.html
However, we will not be using the hacky approach provided by the solution. Instead, we will create a new class called FacebookScopedClient
which will implement IAuthenticationClient
. Then we will simply register the class using:
OAuthWebSecurity.RegisterClient(new FacebookScopedClient("your_app_id", "your_app_secret"), "Facebook", null);
in AuthConfig.cs
The code for the class is:
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
using System.Web;
public class FacebookScopedClient : IAuthenticationClient
{
private string appId;
private string appSecret;
private const string baseUrl = "https://www.facebook.com/dialog/oauth?client_id=";
public const string graphApiToken = "https://graph.facebook.com/oauth/access_token?";
public const string graphApiMe = "https://graph.facebook.com/me?";
private static string GetHTML(string URL)
{
string connectionString = URL;
try
{
System.Net.HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(connectionString);
myRequest.Credentials = CredentialCache.DefaultCredentials;
//// Get the response
WebResponse webResponse = myRequest.GetResponse();
Stream respStream = webResponse.GetResponseStream();
////
StreamReader ioStream = new StreamReader(respStream);
string pageContent = ioStream.ReadToEnd();
//// Close streams
ioStream.Close();
respStream.Close();
return pageContent;
}
catch (Exception)
{
}
return null;
}
private IDictionary<string, string> GetUserData(string accessCode, string redirectURI)
{
string token = GetHTML(graphApiToken + "client_id=" + appId + "&redirect_uri=" + HttpUtility.UrlEncode(redirectURI) + "&client_secret=" + appSecret + "&code=" + accessCode);
if (token == null || token == "")
{
return null;
}
string data = GetHTML(graphApiMe + "fields=id,name,email,gender,link&access_token=" + token.Substring("access_token=", "&"));
// this dictionary must contains
Dictionary<string, string> userData = JsonConvert.DeserializeObject<Dictionary<string, string>>(data);
return userData;
}
public FacebookScopedClient(string appId, string appSecret)
{
this.appId = appId;
this.appSecret = appSecret;
}
public string ProviderName
{
get { return "Facebook"; }
}
public void RequestAuthentication(System.Web.HttpContextBase context, Uri returnUrl)
{
string url = baseUrl + appId + "&redirect_uri=" + HttpUtility.UrlEncode(returnUrl.ToString()) + "&scope=email";
context.Response.Redirect(url);
}
public AuthenticationResult VerifyAuthentication(System.Web.HttpContextBase context)
{
string code = context.Request.QueryString["code"];
string rawUrl = context.Request.Url.OriginalString;
//From this we need to remove code portion
rawUrl = Regex.Replace(rawUrl, "&code=[^&]*", "");
IDictionary<string, string> userData = GetUserData(code, rawUrl);
if (userData == null)
return new AuthenticationResult(false, ProviderName, null, null, null);
string id = userData["id"];
string username = userData["email"];
userData.Remove("id");
userData.Remove("email");
AuthenticationResult result = new AuthenticationResult(true, ProviderName, id, username, userData);
return result;
}
}
now in the
public ActionResult ExternalLoginCallback(string returnUrl)
method in AccountController
, result.ExtraData
should have the email.
Edit: I missed some code in this post. I am adding it below:
public static class String
{
public static string Substring(this string str, string StartString, string EndString)
{
if (str.Contains(StartString))
{
int iStart = str.IndexOf(StartString) + StartString.Length;
int iEnd = str.IndexOf(EndString, iStart);
return str.Substring(iStart, (iEnd - iStart));
}
return null;
}
}
Cheers!