Example controller for OAuth Authentication

AccountController.cs

namespace OAuthDemo.Controllers
{
    using System;
    using System.Web.Mvc;

    [Authorize]
    public class AccountController : Controller
    {
        public ActionResult Logout()
        {
            WebSecurity.Logout();

            return this.RedirectToAction("index", "home");
        }

        [AllowAnonymous]
        public ActionResult LoginExternal(string provider, string returnUrl)
        {
            // Create a URL for the authentication service to return too
            var callback = this.Url.Action("verifyexternallogin", "account", new { returnUrl = returnUrl });

            OAuthWebSecurity.RequestAuthentication(provider, callback);
        }

        [AllowAnonymous]
        public ActionResult VerifyExternalLogin(string returnUrl)
        {
            var result = OAuthWebSecurity.VerifyAuthentication();
            
            if (!result.IsSuccessful)
            {
                // Redirect to a view informing the user it failed
            }

            if (OAuthWebSecurity.Login(result.Provider, result.ProviderUserId, false))
            {
                // This external login has been used before, take the user back where they were
                return this.RedirectToAction("loginredirect", "account", new { returnUrl = returnUrl });
            }

            // Add logic to create a record in your user table
            
            // Create a record in the webpages_OAuthMembership table
            OAuthWebSecurity.CreateOrUpdateAccount(result.Provider, result.ProviderUserId, result.UserName);

            // Try to login again
            OAuthWebSecurity.Login(result.Provider, result.ProviderUserId, false);
            
            // We've create a new user and they're logged in, take them back where they were
            return this.Redirect(returnUrl);
        }
    }
}