SimpleAuthenticationCallbackHandler.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Nancy;
using Nancy.SimpleAuthentication;
using SimpleAuthNancyExample.Models;

namespace SimpleAuthNancyExample.Helpers
{
    public class SampleAuthenticationCallbackHandler : IAuthenticationCallbackProvider
    {
        public dynamic Process(NancyModule nancyModule, AuthenticateCallbackData model)
        {
            return nancyModule.Negotiate.WithView("AuthenticateCallback").WithModel(model);
        }

        public dynamic OnRedirectToAuthenticationProviderError(NancyModule nancyModule, string errorMessage)
        {
            var model = new IndexViewModel
            {
                ErrorMessage = errorMessage
            };

            return nancyModule.View["index", model];
        }
    }
}