now getting username from his id in cookie

Foundation.hs

@@ -68,6 +68,14 @@ instance Yesod App where
         master <- getYesod
         mmsg <- getMessage
         msu <- lookupSession "userId"
+        username <- case msu of 
+          Just a -> do
+            uId <- return $ getUserIdFromText a
+            user <- runDB $ getJust uId
+            return $ userName user
+          otherwise -> do
+            return ("" :: Text)
+
 
         -- We break up the default layout into two components:
         -- default-layout is the contents of the body tag, and

Helper.hs

@@ -1,7 +1,7 @@
 module Helper 
   ( getUserIdFromText
   , extractKey
---  , getUserName
+--  , getUserNameById
   )
 where
 
@@ -27,10 +27,9 @@ extractKey = extractKey' . unKey
     extractKey' (PersistInt64 k) = pack $ show k
     extractKey' _ = ""
 
---getUserName :: Text -> User
+--getUserNameById :: UserId -> Text
---getUserName textId =
+--getUserNameById userId =
 --  let
---    userId = getUserIdFromText textId
+--    user = runDB $ getJust $ userId
---    user = get $ userId
 --  in
---    show user
+--    userName user

templates/default-layout.hamlet

@@ -2,7 +2,7 @@
   <div id="top-nav">
   <ul id="user-nav">
     $maybe userId <- msu
-      Logged in as <a href=@{ProfileR $ getUserIdFromText userId}>$user
+      Logged in as <a href=@{ProfileR $ getUserIdFromText userId}>#{username}
       <li>
         <a href=@{LogoutR}>Logout
       <li>