using System;

using System.Web.Mvc;

using System.Collections.Generic;

using System.Web.Routing; 

using System.Net;

using System.Web;

using System.Text;

using Microsoft.IdentityModel.Tokens;

using System.Security.Principal;

using System.IdentityModel.Tokens.Jwt;

namespace HelloWorldMvcApp

{

    public class SSOFilterAction : ActionFilterAttribute{

          public override void OnActionExecuting(ActionExecutingContext filterContext)

          {

              Log("OnActionExecuting", filterContext.RouteData,"inizio filtro");       

              HttpRequestBase request = filterContext.HttpContext.Request;

              HttpResponseBase response = filterContext.HttpContext.Response;

              HttpCookie consentCookie = request.Cookies["jwt"];

              String redirectUrl = (String)HttpContext.Current.Application ["loginUrl"];

                 if(consentCookie == null){           

                     filterContext.Result = new RedirectResult(redirectUrl, true);

                 } else {

                     if(request.FilePath.Contains("logout")){

                         consentCookie.Expires = DateTime.Now.AddDays(-1);

                         response.Cookies.Add(consentCookie);

                          String logOutUrl = (String)HttpContext.Current.Application ["logoutUrl"];

                         int responseCode=Logout(logOutUrl,consentCookie);

                         if(responseCode==200)

                             Log("OnActionExecuting", filterContext.RouteData,"Cancellati token a seguito di un logOut");  

                        else

                            Log("OnActionExecuting", filterContext.RouteData,"Errore cancellazione token a seguito di un logOut, code: "+responseCode);  

                        filterContext.Result = new RedirectResult(redirectUrl, true);

                     }else{

                         String jwt=consentCookie.Value;

                     }

                    // filterContext.HttpContext.Session["user"] = 

                 }

​

          }

​

        private int Logout(String url,HttpCookie consentCookie)

        {

            try{

                using(WebClient webClient = new WebClient()){

                    var reqparm = new System.Collections.Specialized.NameValueCollection();

                    reqparm.Add("jwt", consentCookie.Value);

                    webClient.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";

                    byte[] responsebytes = webClient.UploadValues(url, "POST", reqparm);

                    String responsebody = Encoding.UTF8.GetString(responsebytes);

                    return 200;

                }

            }catch(WebException ex){

                return (int)((HttpWebResponse)ex.Response).StatusCode;

            }

        }

​

        private void Log(string methodName, RouteData routeData,String stringMessage)

        {

            var controllerName = routeData.Values["controller"];

            var actionName = routeData.Values["action"];

            var message = String.Format("{0} controller:{1} action:{2} message:{3}", methodName, controllerName, actionName,stringMessage);

            Console.WriteLine(message, "Action Filter Log");

        }

        private  bool ValidateToken(string authToken,String key)

        {

            var tokenHandler = new JwtSecurityTokenHandler();

            var validationParameters = GetValidationParameters(key);

​

            SecurityToken validatedToken;

            IPrincipal principal = tokenHandler.ValidateToken(authToken, validationParameters, out validatedToken);

            return true;

        }

​

        private  TokenValidationParameters GetValidationParameters(String key)

        {

            return new TokenValidationParameters()

            {

                ValidateLifetime = false, // Because there is no expiration in the generated token

                ValidateAudience = false, // Because there is no audiance in the generated token

                ValidateIssuer = false,   // Because there is no issuer in the generated token

                ValidIssuer = "Sample",

                ValidAudience = "Sample",

                IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(key)) // The same key as the one that generate the token

            };

        }

    } 

}