Add IMAP session logging as an option

Setting the "sslLogToConsole" parameter to True will now spit out the
IMAP session log inline, prefixed with "HaskellNet-SSL".

src/Network/HaskellNet/SSL.hs

@@ -8,10 +8,12 @@ import Network.Socket.Internal (PortNumber)
 data Settings = Settings
               { sslPort          :: PortNumber
               , sslMaxLineLength :: Int
+              , sslLogToConsole  :: Bool
               }
 
 defaultSettingsWithPort :: PortNumber -> Settings
 defaultSettingsWithPort p = Settings
   { sslPort = p
   , sslMaxLineLength = 10000
+  , sslLogToConsole = False
   }

src/Network/HaskellNet/SSL/Internal.hs

@@ -3,7 +3,6 @@ module Network.HaskellNet.SSL.Internal
   , connectPlain
   ) where
 
-
 import Network.Connection
 import Network.HaskellNet.SSL
 import Network.HaskellNet.BSStream
@@ -11,6 +10,8 @@ import Network.HaskellNet.BSStream
 import qualified Data.ByteString.Char8 as B
 import Data.Default
 
+import Control.Monad ((>=>))
+
 type STARTTLS = IO ()
 
 connectionGetBytes :: Connection -> Int -> IO B.ByteString
@@ -21,13 +22,20 @@ connectionGetBytes = loop B.empty where
 
 connectionToStream :: Connection -> Settings -> BSStream
 connectionToStream c cfg = BSStream
-  { bsGet = connectionGetBytes c
+  { bsGet = connectionGetBytes c >=> withLog "RECV"
-  , bsPut = connectionPut c
+  , bsPut = withLog "SEND" >=> connectionPut c
   , bsFlush = return ()
   , bsClose = connectionClose c
   , bsIsOpen = return True
-  , bsGetLine = connectionGetLine maxl c
+  , bsGetLine = connectionGetLine maxl c >>= withLog "RECV"
   } where maxl = sslMaxLineLength cfg
+          withLog = if sslLogToConsole cfg then logToConsole
+                                           else flip (const . return)
+
+logToConsole :: String -> B.ByteString -> IO B.ByteString
+logToConsole dir s = do
+    putStrLn $ "HaskellNet-SSL " ++ dir ++ ": " ++ show s
+    return s
 
 connectSSL :: String -> Settings -> IO BSStream
 connectSSL hostname cfg = do