yesod/yesod-core/Yesod/Core/Internal/Run.hs
2014-01-27 17:20:02 +02:00

308 lines
12 KiB
Haskell

{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PatternGuards #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE FlexibleContexts #-}
module Yesod.Core.Internal.Run where
import Yesod.Core.Internal.Response
import Blaze.ByteString.Builder (toByteString)
import Control.Applicative ((<$>))
import Control.Exception (fromException, bracketOnError, evaluate)
import qualified Control.Exception as E
import Control.Exception.Lifted (catch)
import Control.Monad.IO.Class (MonadIO)
import Control.Monad.IO.Class (liftIO)
import Control.Monad.Logger (LogLevel (LevelError), LogSource,
liftLoc)
import Control.Monad.Trans.Resource (runResourceT, withInternalState, runInternalState, createInternalState, closeInternalState)
import qualified Data.ByteString as S
import qualified Data.ByteString.Char8 as S8
import qualified Data.IORef as I
import qualified Data.Map as Map
import Data.Maybe (isJust)
import Data.Maybe (fromMaybe)
import Data.Monoid (appEndo, mempty)
import Data.Text (Text)
import qualified Data.Text as T
import Data.Text.Encoding (encodeUtf8)
import Data.Text.Encoding (decodeUtf8With)
import Data.Text.Encoding.Error (lenientDecode)
import Language.Haskell.TH.Syntax (Loc, qLocation)
import qualified Network.HTTP.Types as H
import Network.Wai
#if MIN_VERSION_wai(2, 0, 0)
import Network.Wai.Internal
#endif
import Prelude hiding (catch)
#if !MIN_VERSION_fast_logger(2, 0, 0)
import System.Log.FastLogger (Logger)
#endif
import System.Log.FastLogger (LogStr, toLogStr)
import System.Random (newStdGen)
import Yesod.Core.Content
import Yesod.Core.Class.Yesod
import Yesod.Core.Types
import Yesod.Core.Internal.Request (parseWaiRequest,
tooLargeResponse)
import Yesod.Routes.Class (Route, renderRoute)
-- | Function used internally by Yesod in the process of converting a
-- 'HandlerT' into an 'Application'. Should not be needed by users.
runHandler :: ToTypedContent c
=> RunHandlerEnv site
-> HandlerT site IO c
-> YesodApp
runHandler rhe@RunHandlerEnv {..} handler yreq = withInternalState $ \resState -> do
let toErrorHandler e =
case fromException e of
Just (HCError x) -> x
_ -> InternalError $ T.pack $ show e
istate <- liftIO $ I.newIORef GHState
{ ghsSession = reqSession yreq
, ghsRBC = Nothing
, ghsIdent = 1
, ghsCache = mempty
, ghsHeaders = mempty
}
let hd = HandlerData
{ handlerRequest = yreq
, handlerEnv = rhe
, handlerState = istate
, handlerToParent = const ()
, handlerResource = resState
}
contents' <- catch (fmap Right $ unHandlerT handler hd)
(\e -> return $ Left $ maybe (HCError $ toErrorHandler e) id
$ fromException e)
state <- liftIO $ I.readIORef istate
let finalSession = ghsSession state
let headers = ghsHeaders state
let contents = either id (HCContent defaultStatus . toTypedContent) contents'
let handleError e = flip runInternalState resState $ do
yar <- rheOnError e yreq
{ reqSession = finalSession
}
case yar of
YRPlain status' hs ct c sess ->
let hs' = appEndo headers hs
status
| status' == defaultStatus = getStatus e
| otherwise = status'
in return $ YRPlain status hs' ct c sess
YRWai _ -> return yar
let sendFile' ct fp p =
return $ YRPlain H.status200 (appEndo headers []) ct (ContentFile fp p) finalSession
contents1 <- evaluate contents `E.catch` \e -> return
(HCError $! InternalError $! T.pack $! show (e :: E.SomeException))
case contents1 of
HCContent status (TypedContent ct c) -> do
ec' <- liftIO $ evaluateContent c
case ec' of
Left e -> handleError e
Right c' -> return $ YRPlain status (appEndo headers []) ct c' finalSession
HCError e -> handleError e
HCRedirect status loc -> do
let disable_caching x =
Header "Cache-Control" "no-cache, must-revalidate"
: Header "Expires" "Thu, 01 Jan 1970 05:05:05 GMT"
: x
hs = (if status /= H.movedPermanently301 then disable_caching else id)
$ Header "Location" (encodeUtf8 loc) : appEndo headers []
return $ YRPlain
status hs typePlain emptyContent
finalSession
HCSendFile ct fp p -> catch
(sendFile' ct fp p)
(handleError . toErrorHandler)
HCCreated loc -> do
let hs = Header "Location" (encodeUtf8 loc) : appEndo headers []
return $ YRPlain
H.status201
hs
typePlain
emptyContent
finalSession
HCWai r -> return $ YRWai r
safeEh :: (Loc -> LogSource -> LogLevel -> LogStr -> IO ())
-> ErrorResponse
-> YesodApp
safeEh log' er req = do
liftIO $ log' $(qLocation >>= liftLoc) "yesod-core" LevelError
$ toLogStr $ "Error handler errored out: " ++ show er
return $ YRPlain
H.status500
[]
typePlain
(toContent ("Internal Server Error" :: S.ByteString))
(reqSession req)
-- | Run a 'HandlerT' completely outside of Yesod. This
-- function comes with many caveats and you shouldn't use it
-- unless you fully understand what it's doing and how it works.
--
-- As of now, there's only one reason to use this function at
-- all: in order to run unit tests of functions inside 'HandlerT'
-- but that aren't easily testable with a full HTTP request.
-- Even so, it's better to use @wai-test@ or @yesod-test@ instead
-- of using this function.
--
-- This function will create a fake HTTP request (both @wai@'s
-- 'Request' and @yesod@'s 'Request') and feed it to the
-- @HandlerT@. The only useful information the @HandlerT@ may
-- get from the request is the session map, which you must supply
-- as argument to @runFakeHandler@. All other fields contain
-- fake information, which means that they can be accessed but
-- won't have any useful information. The response of the
-- @HandlerT@ is completely ignored, including changes to the
-- session, cookies or headers. We only return you the
-- @HandlerT@'s return value.
runFakeHandler :: (Yesod site, MonadIO m) =>
SessionMap
-> (site -> Logger)
-> site
-> HandlerT site IO a
-> m (Either ErrorResponse a)
runFakeHandler fakeSessionMap logger site handler = liftIO $ do
ret <- I.newIORef (Left $ InternalError "runFakeHandler: no result")
let handler' = do liftIO . I.writeIORef ret . Right =<< handler
return ()
let yapp = runHandler
RunHandlerEnv
{ rheRender = yesodRender site $ resolveApproot site fakeWaiRequest
, rheRoute = Nothing
, rheSite = site
, rheUpload = fileUpload site
, rheLog = messageLoggerSource site $ logger site
, rheOnError = errHandler
}
handler'
errHandler err req = do
liftIO $ I.writeIORef ret (Left err)
return $ YRPlain
H.status500
[]
typePlain
(toContent ("runFakeHandler: errHandler" :: S8.ByteString))
(reqSession req)
fakeWaiRequest = Request
{ requestMethod = "POST"
, httpVersion = H.http11
, rawPathInfo = "/runFakeHandler/pathInfo"
, rawQueryString = ""
#if MIN_VERSION_wai(2, 0, 0)
, requestHeaderHost = Nothing
#else
, serverName = "runFakeHandler-serverName"
, serverPort = 80
#endif
, requestHeaders = []
, isSecure = False
, remoteHost = error "runFakeHandler-remoteHost"
, pathInfo = ["runFakeHandler", "pathInfo"]
, queryString = []
, requestBody = mempty
, vault = mempty
, requestBodyLength = KnownLength 0
}
fakeRequest =
YesodRequest
{ reqGetParams = []
, reqCookies = []
, reqWaiRequest = fakeWaiRequest
, reqLangs = []
, reqToken = Just "NaN" -- not a nonce =)
, reqAccept = []
, reqSession = fakeSessionMap
}
_ <- runResourceT $ yapp fakeRequest
I.readIORef ret
{-# WARNING runFakeHandler "Usually you should *not* use runFakeHandler unless you really understand how it works and why you need it." #-}
yesodRunner :: (ToTypedContent res, Yesod site)
=> HandlerT site IO res
-> YesodRunnerEnv site
-> Maybe (Route site)
-> Application
yesodRunner handler' YesodRunnerEnv {..} route req
| Just maxLen <- mmaxLen, KnownLength len <- requestBodyLength req, maxLen < len = return tooLargeResponse
| otherwise = do
let dontSaveSession _ = return []
(session, saveSession) <- liftIO $ do
maybe (return (Map.empty, dontSaveSession)) (\sb -> sbLoadSession sb req) yreSessionBackend
let mkYesodReq = parseWaiRequest req session (isJust yreSessionBackend) mmaxLen
yreq <-
case mkYesodReq of
Left yreq -> return yreq
Right needGen -> liftIO $ needGen <$> newStdGen
let ra = resolveApproot yreSite req
let log' = messageLoggerSource yreSite yreLogger
-- We set up two environments: the first one has a "safe" error handler
-- which will never throw an exception. The second one uses the
-- user-provided errorHandler function. If that errorHandler function
-- errors out, it will use the safeEh below to recover.
rheSafe = RunHandlerEnv
{ rheRender = yesodRender yreSite ra
, rheRoute = route
, rheSite = yreSite
, rheUpload = fileUpload yreSite
, rheLog = log'
, rheOnError = safeEh log'
}
rhe = rheSafe
{ rheOnError = runHandler rheSafe . errorHandler
}
#if MIN_VERSION_wai(2, 0, 0)
bracketOnError createInternalState closeInternalState $ \is -> do
yar <- runInternalState (runHandler rhe handler yreq) is
liftIO $ yarToResponse yar saveSession yreq req is
#else
yar <- runHandler rhe handler yreq
liftIO $ yarToResponse yar saveSession yreq req
#endif
where
mmaxLen = maximumContentLength yreSite route
handler = yesodMiddleware handler'
yesodRender :: Yesod y
=> y
-> ResolvedApproot
-> Route y
-> [(Text, Text)] -- ^ url query string
-> Text
yesodRender y ar url params =
decodeUtf8With lenientDecode $ toByteString $
fromMaybe
(joinPath y ar ps
$ params ++ params')
(urlRenderOverride y url)
where
(ps, params') = renderRoute url
resolveApproot :: Yesod master => master -> Request -> ResolvedApproot
resolveApproot master req =
case approot of
ApprootRelative -> ""
ApprootStatic t -> t
ApprootMaster f -> f master
ApprootRequest f -> f master req
stripHandlerT :: HandlerT child (HandlerT parent m) a
-> (parent -> child)
-> (Route child -> Route parent)
-> Maybe (Route child)
-> HandlerT parent m a
stripHandlerT (HandlerT f) getSub toMaster newRoute = HandlerT $ \hd -> do
let env = handlerEnv hd
($ hd) $ unHandlerT $ f hd
{ handlerEnv = env
{ rheSite = getSub $ rheSite env
, rheRoute = newRoute
, rheRender = \url params -> rheRender env (toMaster url) params
}
, handlerToParent = toMaster
}