From a2d26e096d270bad62d70c2d9c6866d82249a245 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Tue, 12 Mar 2013 10:41:17 +0200
Subject: [PATCH] Move session header logic to yarToResponse

---
 yesod-core/Yesod/Core/Internal/Response.hs | 43 ++++++++++++++--------
 yesod-core/Yesod/Core/Internal/Run.hs      | 13 +------
 2 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/yesod-core/Yesod/Core/Internal/Response.hs b/yesod-core/Yesod/Core/Internal/Response.hs
index 604a6f56..814e99ff 100644
--- a/yesod-core/Yesod/Core/Internal/Response.hs
+++ b/yesod-core/Yesod/Core/Internal/Response.hs
@@ -22,23 +22,34 @@ import           Control.Exception            (SomeException, handle)
 import           Blaze.ByteString.Builder     (fromLazyByteString,
                                                toLazyByteString)
 import qualified Data.ByteString.Lazy         as L
+import qualified Data.Map                     as Map
+import           Yesod.Core.Internal.Request  (tokenKey)
+import           Data.Text.Encoding           (encodeUtf8)
 
-yarToResponse :: YesodResponse -> [(CI ByteString, ByteString)] -> Response
-yarToResponse (YRWai a) _ = a
-yarToResponse (YRPlain s hs _ c _) extraHeaders =
-    go c
-  where
-    finalHeaders = extraHeaders ++ map headerToPair hs
-    finalHeaders' len = ("Content-Length", S8.pack $ show len)
-                      : finalHeaders
-
-    go (ContentBuilder b mlen) =
-        ResponseBuilder s hs' b
-      where
-        hs' = maybe finalHeaders finalHeaders' mlen
-    go (ContentFile fp p) = ResponseFile s finalHeaders fp p
-    go (ContentSource body) = ResponseSource s finalHeaders body
-    go (ContentDontEvaluate c') = go c'
+yarToResponse :: Monad m
+              => YesodResponse
+              -> (SessionMap -> m [Header]) -- ^ save session
+              -> YesodRequest
+              -> m Response
+yarToResponse (YRWai a) _ _ = return a
+yarToResponse (YRPlain s hs ct c newSess) saveSession yreq = do
+    extraHeaders <- do
+        let nsToken = maybe
+                newSess
+                (\n -> Map.insert tokenKey (encodeUtf8 n) newSess)
+                (reqToken yreq)
+        sessionHeaders <- saveSession nsToken
+        return $ ("Content-Type", ct) : map headerToPair sessionHeaders
+    let finalHeaders = extraHeaders ++ map headerToPair hs
+        finalHeaders' len = ("Content-Length", S8.pack $ show len)
+                          : finalHeaders
+    let go (ContentBuilder b mlen) =
+            let hs' = maybe finalHeaders finalHeaders' mlen
+             in ResponseBuilder s hs' b
+        go (ContentFile fp p) = ResponseFile s finalHeaders fp p
+        go (ContentSource body) = ResponseSource s finalHeaders body
+        go (ContentDontEvaluate c') = go c'
+    return $ go c
 
 -- | Convert Header to a key/value pair.
 headerToPair :: Header
diff --git a/yesod-core/Yesod/Core/Internal/Run.hs b/yesod-core/Yesod/Core/Internal/Run.hs
index 94f07a14..1017ab2f 100644
--- a/yesod-core/Yesod/Core/Internal/Run.hs
+++ b/yesod-core/Yesod/Core/Internal/Run.hs
@@ -37,7 +37,7 @@ import           System.Random                (newStdGen)
 import           Yesod.Core.Content
 import           Yesod.Core.Class.Yesod
 import           Yesod.Core.Types
-import           Yesod.Core.Internal.Request  (parseWaiRequest, tokenKey,
+import           Yesod.Core.Internal.Request  (parseWaiRequest,
                                                tooLargeResponse)
 import           Yesod.Routes.Class           (Route, renderRoute)
 
@@ -241,16 +241,7 @@ yesodRunner handler' YesodRunnerEnv {..} req
             { rheOnError = runHandler rheSafe . errorHandler
             }
     yar <- runHandler rhe handler yreq
-    extraHeaders <- case yar of
-        (YRPlain _ _ ct _ newSess) -> do
-            let nsToken = maybe
-                    newSess
-                    (\n -> Map.insert tokenKey (encodeUtf8 n) newSess)
-                    (reqToken yreq)
-            sessionHeaders <- liftIO (saveSession nsToken)
-            return $ ("Content-Type", ct) : map headerToPair sessionHeaders
-        _ -> return []
-    return $ yarToResponse yar extraHeaders
+    liftIO $ yarToResponse yar saveSession yreq
   where
     maxLen = maximumContentLength yreMaster $ fmap yreToMaster yreRoute
     handler = yesodMiddleware handler'