+{-# LANGUAGE
+ Arrows
+ , DeriveDataTypeable
+ , TypeOperators
+ , UnicodeSyntax
+ #-}
+
+-- |Aborting the computation of 'Network.HTTP.Lucu.Resource.Resource'
+-- in any 'Prelude.IO' monads or arrows.
module Network.HTTP.Lucu.Abortion
( Abortion(..)
, abort
+ , abortPurely
, abortSTM
, abortA
, abortPage
)
where
-
-import Control.Arrow
-import Control.Arrow.ArrowIO
-import Control.Concurrent.STM
-import Control.Exception
-import Control.Monad.Trans
-import GHC.Conc (unsafeIOToSTM)
-import Data.Dynamic
-import Network.HTTP.Lucu.Config
-import Network.HTTP.Lucu.DefaultPage
-import Network.HTTP.Lucu.Headers
-import Network.HTTP.Lucu.HttpVersion
-import Network.HTTP.Lucu.Request
-import Network.HTTP.Lucu.Response
-import System.IO.Unsafe
-import Text.XML.HXT.Arrow.WriteDocument
-import Text.XML.HXT.Arrow.XmlArrow
-import Text.XML.HXT.Arrow.XmlIOStateArrow
-import Text.XML.HXT.DOM.XmlKeywords
-
+import Control.Arrow
+import Control.Arrow.ListArrow
+import Control.Arrow.Unicode
+import Control.Concurrent.STM
+import Control.Exception
+import Control.Monad.Trans
+import Data.Ascii (Ascii, CIAscii)
+import Data.Text (Text)
+import qualified Data.Text as T
+import qualified Data.Text.Lazy as Lazy
+import Data.Typeable
+import Network.HTTP.Lucu.Config
+import Network.HTTP.Lucu.DefaultPage
+import Network.HTTP.Lucu.Headers
+import Network.HTTP.Lucu.Request
+import Network.HTTP.Lucu.Response
+import Prelude.Unicode
+import Text.XML.HXT.Arrow.WriteDocument
+import Text.XML.HXT.Arrow.XmlArrow
+import Text.XML.HXT.Arrow.XmlState
data Abortion = Abortion {
- aboStatus :: StatusCode
- , aboHeaders :: Headers
- , aboMessage :: Maybe String
- } deriving (Show, Typeable)
+ aboStatus :: !StatusCode
+ , aboHeaders :: !Headers
+ , aboMessage :: !(Maybe Text)
+ } deriving (Eq, Show, Typeable)
+instance Exception Abortion
-abort :: MonadIO m => StatusCode -> [ (String, String) ] -> Maybe String -> m a
-abort status headers msg
- = let abo = Abortion status headers msg
- exc = DynException (toDyn abo)
- in
- liftIO $ throwIO exc
+-- |Computation of @'abort' status headers msg@ aborts the
+-- 'Network.HTTP.Lucu.Resource.Resource' monad with given status,
+-- additional response headers, and optional message string.
+--
+-- What this really does is to throw a special
+-- 'Control.Exception.Exception'. The exception will be caught by the
+-- Lucu system.
+--
+-- 1. If the 'Network.HTTP.Lucu.Resource.Resource' is in the /Deciding
+-- Header/ or any precedent states, it is possible to use the
+-- @status@ and such like as a HTTP response to be sent to the
+-- client.
+--
+-- 2. Otherwise the HTTP response can't be modified anymore so the
+-- only possible thing the system can do is to dump it to the
+-- stderr. See
+-- 'Network.HTTP.Lucu.Config.cnfDumpTooLateAbortionToStderr'.
+--
+-- Note that the status code doesn't have to be an error code so you
+-- can use this action for redirection as well as error reporting e.g.
+--
+-- > abort MovedPermanently
+-- > [("Location", "http://example.net/")]
+-- > (Just "It has been moved to example.net")
+abort :: MonadIO m ⇒ StatusCode → [ (CIAscii, Ascii) ] → Maybe Text → m a
+{-# INLINE abort #-}
+abort status headers
+ = liftIO ∘ throwIO ∘ Abortion status (toHeaders headers)
+-- |This is similar to 'abort' but computes it with
+-- 'System.IO.Unsafe.unsafePerformIO'.
+abortPurely :: StatusCode → [ (CIAscii, Ascii) ] → Maybe Text → a
+{-# INLINE abortPurely #-}
+abortPurely status headers
+ = throw ∘ Abortion status (toHeaders headers)
-abortSTM :: StatusCode -> [ (String, String) ] -> Maybe String -> STM a
-abortSTM status headers msg
- = unsafeIOToSTM $ abort status headers msg
-
-
-abortA :: ArrowIO a => a (StatusCode, ([ (String, String) ], Maybe String)) c
-abortA
- = arrIO3 abort
+-- |Computation of @'abortSTM' status headers msg@ just computes
+-- 'abort' in a 'Control.Monad.STM.STM' monad.
+abortSTM :: StatusCode → [ (CIAscii, Ascii) ] → Maybe Text → STM a
+{-# INLINE abortSTM #-}
+abortSTM status headers
+ = throwSTM ∘ Abortion status (toHeaders headers)
+-- | Computation of @'abortA' -< (status, (headers, msg))@ just
+-- computes 'abort' in an 'Control.Arrow.ArrowIO.ArrowIO'.
+abortA :: Arrow (⇝) ⇒ (StatusCode, ([ (CIAscii, Ascii) ], Maybe Text)) ⇝ c
+{-# INLINE abortA #-}
+abortA = proc (status, (headers, msg)) →
+ returnA ⤙ abortPurely status headers msg
-- aboMessage が Just なら單に mkDefaultPage に渡すだけで良いので樂だが、
-- Nothing の場合は getDefaultPage を使ってデフォルトのメッセージを得な
-- ければならない。
-abortPage :: Config -> Maybe Request -> Response -> Abortion -> String
+abortPage :: Config → Maybe Request → Response → Abortion → Lazy.Text
abortPage conf reqM res abo
= case aboMessage abo of
Just msg
- -> let [html] = unsafePerformIO
- $ runX ( mkDefaultPage conf (aboStatus abo) (txt msg)
- >>>
- writeDocumentToString [(a_indent, v_1)]
- )
- in
- html
+ → let [html] = runLA ( mkDefaultPage conf (aboStatus abo) (txt $ T.unpack msg)
+ ⋙
+ writeDocumentToString [ withIndent True ]
+ ) ()
+ in
+ Lazy.pack html
Nothing
- -> let res' = res { resStatus = aboStatus abo }
- res'' = foldl (.) id [setHeader name value
- | (name, value) <- aboHeaders abo]
- $ res'
+ → let res' = res { resStatus = aboStatus abo }
+ res'' = foldl (∘) id [setHeader name value
+ | (name, value) ← fromHeaders $ aboHeaders abo] res'
in
getDefaultPage conf reqM res''
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