From b9b2d0d609199dcdcb8b2f76182162b6df1bed1e Mon Sep 17 00:00:00 2001
From: David Turner <dave.c.turner@gmail.com>
Date: Fri, 13 Nov 2015 13:40:19 +0000
Subject: [PATCH] Use AutoUpdate for session expiry date too

---
 yesod-core/Yesod/Core/Internal/Session.hs | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/yesod-core/Yesod/Core/Internal/Session.hs b/yesod-core/Yesod/Core/Internal/Session.hs
index dd9ebc61..03240abf 100644
--- a/yesod-core/Yesod/Core/Internal/Session.hs
+++ b/yesod-core/Yesod/Core/Internal/Session.hs
@@ -16,6 +16,7 @@ import Control.Monad (forever, guard)
 import Yesod.Core.Types
 import Yesod.Core.Internal.Util
 import qualified Data.IORef as I
+import Control.AutoUpdate
 
 encodeClientSession :: CS.Key
                     -> CS.IV
@@ -54,15 +55,15 @@ clientSessionDateCacher ::
      NominalDiffTime -- ^ Inactive session valitity.
   -> IO (IO ClientSessionDateCache, IO ())
 clientSessionDateCacher validity = do
-    ref <- getUpdated >>= I.newIORef
-    tid <- forkIO $ forever (doUpdate ref)
-    return $! (I.readIORef ref, killThread tid)
+    getClientSessionDateCache <- mkAutoUpdate defaultUpdateSettings
+      { updateAction = getUpdated
+      , updateFreq   = 10000000 -- 10s
+      }
+
+    return $! (getClientSessionDateCache, return ())
   where
     getUpdated = do
       now <- getCurrentTime
       let expires  = validity `addUTCTime` now
           expiresS = runPut (putTime expires)
       return $! ClientSessionDateCache now expires expiresS
-    doUpdate ref = do
-      threadDelay 10000000 -- 10s
-      I.writeIORef ref =<< getUpdated