yesod/yesod-core/Yesod/Core/Internal/Run.hs
2013-03-13 08:48:28 +02:00

312 lines
12 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PatternGuards #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE FlexibleContexts #-}
module Yesod.Core.Internal.Run where
import Yesod.Core.Internal.Response
import Yesod.Core.Class.Handler
import Blaze.ByteString.Builder (toByteString)
import Control.Applicative ((<$>))
import Control.Exception (fromException)
import Control.Exception.Lifted (catch, finally)
import Control.Monad.IO.Class (MonadIO)
import Control.Monad.IO.Class (liftIO)
import Control.Monad.Base (liftBase)
import Control.Monad.Logger (LogLevel (LevelError), LogSource,
liftLoc)
import Control.Monad.Trans.Resource (runResourceT)
import Control.Monad.Trans.Control (MonadBaseControl)
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
import Prelude hiding (catch)
import System.Log.FastLogger (Logger)
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
-- 'GHandler' into an 'Application'. Should not be needed by users.
runHandler :: ToTypedContent c
=> RunHandlerEnv sub master
-> GHandler sub master c
-> YesodApp
runHandler rhe@RunHandlerEnv {..} handler yreq = 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
}
contents' <- catch (fmap Right $ unGHandler 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 H.status200 . toTypedContent) contents'
let handleError e = do
yar <- rheOnError e yreq
{ reqSession = finalSession
}
case yar of
YRPlain _ hs ct c sess ->
let hs' = appEndo headers hs
in return $ YRPlain (getStatus e) hs' ct c sess
YRWai _ -> return yar
let sendFile' ct fp p =
return $ YRPlain H.status200 (appEndo headers []) ct (ContentFile fp p) finalSession
case contents 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 'GHandler' 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 'GHandler'
-- 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
-- @GHandler@. The only useful information the @GHandler@ 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
-- @GHandler@ is completely ignored, including changes to the
-- session, cookies or headers. We only return you the
-- @GHandler@'s return value.
runFakeHandler :: (Yesod master, MonadIO m) =>
SessionMap
-> (master -> Logger)
-> master
-> GHandler master master a
-> m (Either ErrorResponse a)
runFakeHandler fakeSessionMap logger master 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 master $ resolveApproot master fakeWaiRequest
, rheRoute = Nothing
, rheToMaster = id
, rheMaster = master
, rheSub = master
, rheUpload = fileUpload master
, rheLog = messageLoggerSource master $ logger master
, 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 = ""
, serverName = "runFakeHandler-serverName"
, serverPort = 80
, 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 master)
=> GHandler sub master res
-> YesodRunnerEnv sub master
-> Maybe (Route sub)
-> Application
yesodRunner handler' YesodRunnerEnv {..} route req
| 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) maxLen
yreq <-
case mkYesodReq of
Left yreq -> return yreq
Right needGen -> liftIO $ needGen <$> newStdGen
let ra = resolveApproot yreMaster req
let log' = messageLoggerSource yreMaster 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 yreMaster ra
, rheRoute = route
, rheToMaster = yreToMaster
, rheMaster = yreMaster
, rheSub = yreSub
, rheUpload = fileUpload yreMaster
, rheLog = log'
, rheOnError = safeEh log'
}
rhe = rheSafe
{ rheOnError = runHandler rheSafe . errorHandler
}
yar <- runHandler rhe handler yreq
liftIO $ yarToResponse yar saveSession yreq
where
maxLen = maximumContentLength yreMaster $ fmap yreToMaster 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
fixEnv :: (oldSub -> newSub)
-> (Route newSub -> Route oldSub)
-> YesodRunnerEnv oldSub master
-> YesodRunnerEnv newSub master
fixEnv toNewSub toOldRoute envOld =
envOld
{ yreSub = toNewSub $ yreSub envOld
, yreToMaster = yreToMaster envOld . toOldRoute
}
stripHandlerT :: (HandlerState m, MonadBaseControl IO m)
=> HandlerT sub m a
-> (HandlerMaster m -> sub)
-> (Route sub -> Route (HandlerMaster m))
-> Maybe (Route sub)
-> m a
stripHandlerT (HandlerT f) getSub toMaster newRoute = do
yreq <- askYesodRequest
env <- askHandlerEnv
ghs <- getGHState
ighs <- liftBase $ I.newIORef ghs
let sub = getSub $ rheMaster env
hd = HandlerData
{ handlerRequest = yreq
, handlerEnv = env
{ rheMaster = sub
, rheSub = sub
, rheToMaster = id
, rheRoute = newRoute
, rheRender = \url params -> rheRender env (toMaster url) params
}
, handlerState = ighs
}
f hd `finally` (liftBase (I.readIORef ighs) >>= putGHState)