Facebook OAuth login

OAuth.aspx.cs

using System;
using Skybrud.Social.Facebook;
using Skybrud.Social.Facebook.OAuth;

namespace Skybrud.Social.Test.Facebook {
    
    public partial class OAuth : System.Web.UI.Page {
        
        protected void Page_Load(object sender, EventArgs e) {

            FacebookOAuthClient oauth = new FacebookOAuthClient {
                AppId = "---",
                AppSecret = "---",
                ReturnUri = "http://social.abjerner/Facebook/OAuth.aspx"
            };

            string code = Request.QueryString["code"];
            string action = Request.QueryString["do"];

            if (action == "login") {

                // Get the redirect URI (if present)
                string redirect = (Request.QueryString["redirect"] ?? "/");

                // Set the state
                string state = Guid.NewGuid().ToString();
                Session["Facebook_" + state] = redirect;

                // Construct the authorization URL
                string authorizatioUrl = oauth.GetAuthorizationUrl(
                    state,
                    FacebookScope.ReadStream + FacebookScope.PublishStream
                );

                // Redirect the user to the OAuth dialog
                Response.Redirect(authorizatioUrl);

            } else if (code == null) { 
                
                Content.Text += "<a href=\"?do=login\" class=\"button\">Login with Facebook</a>";

            } else {

                // Get the state from the query string
                string state = Request.QueryString["state"];

                // Validate state - Step 1
                if (state == null) {
                    Content.Text += "<div class=\"error\">No <strong>state</strong> specified in the query string.</div>";
                    return;
                }

                // Validate state - Step 2
                string session = Session["Facebook_" + state] as string;
                if (session == null) {
                    Content.Text += "<div class=\"error\">Session expired?</div>";
                    return;
                }

                // Remove the state from the session
                Session.Remove("facebook_" + state);

                // Exchange the auth code for an access token
                string accessToken = oauth.GetAccessTokenFromAuthCode(code);

                // Do your thing here
                Content.Text += "<p><strong>Access token:</strong> " + accessToken + "</p>";

            }

        }
    
    }

}