Fixed Shibboleth Return Url

src/STS/Controllers/ShibbolethController.cs

@@ -135,6 +135,7 @@ namespace Coscine.Api.STS.Controllers
             result = await _signInManager.UserManager.AddLoginAsync(coscineUser, info);
             await _signInManager.SignInAsync(coscineUser, isPersistent: false);
 
+            returnUrl = Program.MainUrl + "/?redirect=" + ((returnUrl != null) ? Uri.EscapeDataString(returnUrl) : "");
             return Redirect(UrlGenerator.ExtendReturnUrl(returnUrl, Request));
         }
 
@@ -147,7 +148,7 @@ namespace Coscine.Api.STS.Controllers
         /// <param name="entityId">Specific Identitiy Provider to be redirect to</param>
         /// <returns>ChallengeResult</returns>
         [Route("[controller]/login")]
-        public ActionResult Login(string returnUrl = "/", string entityId = null)
+        public ActionResult Login(string returnUrl = null, string entityId = null)
         {
             var provider = "Saml2";
             var redirectUrl = Program.MainUrl + "/Shibboleth/callback?returnUrl=" + returnUrl;