yesod/yesod-core/Yesod/Core/Internal/Session.hs
2013-03-12 05:49:24 +02:00

69 lines
2.3 KiB
Haskell

module Yesod.Core.Internal.Session
( encodeClientSession
, decodeClientSession
, clientSessionDateCacher
, ClientSessionDateCache(..)
, SaveSession
, SessionBackend(..)
) where
import qualified Web.ClientSession as CS
import Data.Serialize
import Data.Time
import Data.ByteString (ByteString)
import Control.Concurrent (forkIO, killThread, threadDelay)
import Control.Monad (forever, guard)
import Yesod.Core.Types
import Yesod.Core.Internal.Util
import qualified Data.IORef as I
encodeClientSession :: CS.Key
-> CS.IV
-> ClientSessionDateCache -- ^ expire time
-> ByteString -- ^ remote host
-> SessionMap -- ^ session
-> ByteString -- ^ cookie value
encodeClientSession key iv date rhost session' =
CS.encrypt key iv $ encode $ SessionCookie expires rhost session'
where expires = Right (csdcExpiresSerialized date)
decodeClientSession :: CS.Key
-> ClientSessionDateCache -- ^ current time
-> ByteString -- ^ remote host field
-> ByteString -- ^ cookie value
-> Maybe SessionMap
decodeClientSession key date rhost encrypted = do
decrypted <- CS.decrypt key encrypted
SessionCookie (Left expire) rhost' session' <-
either (const Nothing) Just $ decode decrypted
guard $ expire > csdcNow date
guard $ rhost' == rhost
return session'
----------------------------------------------------------------------
-- Mostly copied from Kazu's date-cache, but with modifications
-- that better suit our needs.
--
-- The cached date is updated every 10s, we don't need second
-- resolution for session expiration times.
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)
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