Request for Tutorial to add Openid Support to NerdDinner ASP.NET MVC application

I'm looking learn about ASP.NET MVC and OpenId using the ASP.NET MVC NerdDinner tutorial.

I would like to replace the Authentication system in NerdDinner to be OpenId only. I've downloaded the latest DotNetOpenAuth libraries but I'm not sure how to put it all together. Can anyone help with a quick step-by-step tutorial?

Is this as simple as dropping in the library or are there significant changes needed to the application as well?

Best Solution

Once you download dotnetopenid, look in the samples\RelyingPartyMvc directory. There is a sample where they replace the default MVC authentication system with OpenID. The relevant code is in Controllers/UserController.cs. Here is the Authenticate action:

//Stage 1: Show form asking for Open ID identifier URL
var openid = new OpenIdRelyingParty();
if (openid.Response == null) {
    // Stage 2: user submitting Identifier
    Identifier id;
    if (Identifier.TryParse(Request.Form["openid_identifier"], out id)) {
    } else {
            ViewData["Message"] = "Invalid identifier";
            return View("Login");
} else {
    // Stage 3: OpenID Provider sending assertion response
    switch (openid.Response.Status) {
        case AuthenticationStatus.Authenticated:
            FormsAuthentication.RedirectFromLoginPage(openid.Response.ClaimedIdentifier, false);
        case AuthenticationStatus.Canceled:
            ViewData["Message"] = "Canceled at provider";
            return View("Login");
        case AuthenticationStatus.Failed:
            ViewData["Message"] = openid.Response.Exception.Message;
            return View("Login");
return new EmptyResult();
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