390 lines
15 KiB
Haskell
390 lines
15 KiB
Haskell
{-# LANGUAGE CPP #-}
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE PatternGuards #-}
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{-# LANGUAGE RankNTypes #-}
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{-# LANGUAGE RecordWildCards #-}
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{-# LANGUAGE TemplateHaskell #-}
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{-# LANGUAGE TupleSections #-}
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{-# LANGUAGE FlexibleContexts #-}
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module Yesod.Core.Internal.Run where
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#if __GLASGOW_HASKELL__ < 710
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import Data.Monoid (Monoid, mempty)
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import Control.Applicative ((<$>))
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#endif
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import Yesod.Core.Internal.Response
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import Data.ByteString.Builder (toLazyByteString)
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import qualified Data.ByteString.Lazy as BL
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import Control.Exception (fromException, evaluate)
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import qualified Control.Exception as E
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import Control.Monad.IO.Class (MonadIO, liftIO)
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import Control.Monad.Logger (LogLevel (LevelError), LogSource,
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liftLoc)
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import Control.Monad.Trans.Resource (runResourceT, withInternalState, runInternalState, InternalState)
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import qualified Data.ByteString as S
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import qualified Data.ByteString.Char8 as S8
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import qualified Data.IORef as I
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import qualified Data.Map as Map
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import Data.Maybe (isJust, fromMaybe)
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import Data.Monoid (appEndo)
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import Data.Text (Text)
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import qualified Data.Text as T
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import Data.Text.Encoding (encodeUtf8, decodeUtf8With)
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import Data.Text.Encoding.Error (lenientDecode)
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import Language.Haskell.TH.Syntax (Loc, qLocation)
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import qualified Network.HTTP.Types as H
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import Network.Wai
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import Network.Wai.Internal
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import System.Log.FastLogger (LogStr, toLogStr)
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import Yesod.Core.Content
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import Yesod.Core.Class.Yesod
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import Yesod.Core.Types
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import Yesod.Core.Internal.Request (parseWaiRequest,
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tooLargeResponse)
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import Yesod.Core.Internal.Util (getCurrentMaxExpiresRFC1123)
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import Yesod.Routes.Class (Route, renderRoute)
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import Control.DeepSeq (($!!), NFData)
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-- | Catch all synchronous exceptions, ignoring asynchronous
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-- exceptions.
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--
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-- Ideally we'd use this from a different library
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catchSync :: IO a -> (E.SomeException -> IO a) -> IO a
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catchSync thing after = thing `E.catch` \e ->
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if isAsyncException e
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then E.throwIO e
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else after e
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-- | Determine if an exception is asynchronous
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--
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-- Also worth being upstream
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isAsyncException :: E.SomeException -> Bool
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isAsyncException e =
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case fromException e of
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Just E.SomeAsyncException{} -> True
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Nothing -> False
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-- | Convert an exception into an ErrorResponse
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toErrorHandler :: E.SomeException -> IO ErrorResponse
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toErrorHandler e0 = flip catchSync errFromShow $
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case fromException e0 of
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Just (HCError x) -> evaluate $!! x
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_
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| isAsyncException e0 -> E.throwIO e0
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| otherwise -> errFromShow e0
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-- | Generate an @ErrorResponse@ based on the shown version of the exception
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errFromShow :: E.SomeException -> IO ErrorResponse
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errFromShow x = evaluate $!! InternalError $! T.pack $! show x
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-- | Do a basic run of a handler, getting some contents and the final
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-- @GHState@. The @GHState@ unfortunately may contain some impure
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-- exceptions, but all other synchronous exceptions will be caught and
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-- represented by the @HandlerContents@.
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basicRunHandler :: ToTypedContent c
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=> RunHandlerEnv site
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-> HandlerFor site c
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-> YesodRequest
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-> InternalState
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-> IO (GHState, HandlerContents)
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basicRunHandler rhe handler yreq resState = do
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-- Create a mutable ref to hold the state. We use mutable refs so
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-- that the updates will survive runtime exceptions.
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istate <- I.newIORef defState
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-- Run the handler itself, capturing any runtime exceptions and
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-- converting them into a @HandlerContents@
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contents' <- catchSync
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(do
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res <- unHandlerFor handler (hd istate)
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tc <- evaluate (toTypedContent res)
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-- Success! Wrap it up in an @HCContent@
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return (HCContent defaultStatus tc))
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(\e ->
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case fromException e of
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Just e' -> return e'
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Nothing -> HCError <$> toErrorHandler e)
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-- Get the raw state and return
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state <- I.readIORef istate
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return (state, contents')
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where
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defState = GHState
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{ ghsSession = reqSession yreq
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, ghsRBC = Nothing
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, ghsIdent = 1
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, ghsCache = mempty
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, ghsCacheBy = mempty
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, ghsHeaders = mempty
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}
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hd istate = HandlerData
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{ handlerRequest = yreq
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, handlerEnv = rhe
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, handlerState = istate
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, handlerResource = resState
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}
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-- | Convert an @ErrorResponse@ into a @YesodResponse@
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handleError :: RunHandlerEnv site
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-> YesodRequest
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-> InternalState
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-> Map.Map Text S8.ByteString
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-> [Header]
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-> ErrorResponse
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-> IO YesodResponse
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handleError rhe yreq resState finalSession headers e0 = do
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-- Find any evil hidden impure exceptions
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e <- (evaluate $!! e0) `catchSync` errFromShow
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-- Generate a response, leveraging the updated session and
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-- response headers
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flip runInternalState resState $ do
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yar <- rheOnError rhe e yreq
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{ reqSession = finalSession
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}
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case yar of
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YRPlain status' hs ct c sess ->
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let hs' = headers ++ hs
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status
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| status' == defaultStatus = getStatus e
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| otherwise = status'
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in return $ YRPlain status hs' ct c sess
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YRWai _ -> return yar
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YRWaiApp _ -> return yar
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-- | Convert a @HandlerContents@ into a @YesodResponse@
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handleContents :: (ErrorResponse -> IO YesodResponse)
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-> Map.Map Text S8.ByteString
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-> [Header]
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-> HandlerContents
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-> IO YesodResponse
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handleContents handleError' finalSession headers contents =
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case contents of
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HCContent status (TypedContent ct c) -> do
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-- Check for impure exceptions hiding in the contents
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ec' <- evaluateContent c
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case ec' of
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Left e -> handleError' e
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Right c' -> return $ YRPlain status headers ct c' finalSession
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HCError e -> handleError' e
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HCRedirect status loc -> do
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let disable_caching x =
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Header "Cache-Control" "no-cache, must-revalidate"
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: Header "Expires" "Thu, 01 Jan 1970 05:05:05 GMT"
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: x
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hs = (if status /= H.movedPermanently301 then disable_caching else id)
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$ Header "Location" (encodeUtf8 loc) : headers
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return $ YRPlain
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status hs typePlain emptyContent
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finalSession
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HCSendFile ct fp p -> return $ YRPlain
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H.status200
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headers
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ct
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(ContentFile fp p)
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finalSession
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HCCreated loc -> return $ YRPlain
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H.status201
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(Header "Location" (encodeUtf8 loc) : headers)
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typePlain
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emptyContent
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finalSession
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HCWai r -> return $ YRWai r
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HCWaiApp a -> return $ YRWaiApp a
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-- | Evaluate the given value. If an exception is thrown, use it to
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-- replace the provided contents and then return @mempty@ in place of the
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-- evaluated value.
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evalFallback :: (Monoid w, NFData w)
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=> HandlerContents
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-> w
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-> IO (w, HandlerContents)
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evalFallback contents val = catchSync
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(fmap (, contents) (evaluate $!! val))
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(fmap ((mempty, ) . HCError) . toErrorHandler)
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-- | Function used internally by Yesod in the process of converting a
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-- 'HandlerT' into an 'Application'. Should not be needed by users.
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runHandler :: ToTypedContent c
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=> RunHandlerEnv site
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-> HandlerFor site c
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-> YesodApp
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runHandler rhe@RunHandlerEnv {..} handler yreq = withInternalState $ \resState -> do
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-- Get the raw state and original contents
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(state, contents0) <- basicRunHandler rhe handler yreq resState
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-- Evaluate the unfortunately-lazy session and headers,
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-- propagating exceptions into the contents
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(finalSession, contents1) <- evalFallback contents0 (ghsSession state)
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(headers, contents2) <- evalFallback contents1 (appEndo (ghsHeaders state) [])
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-- Convert the HandlerContents into the final YesodResponse
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handleContents
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(handleError rhe yreq resState finalSession headers)
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finalSession
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headers
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contents2
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safeEh :: (Loc -> LogSource -> LogLevel -> LogStr -> IO ())
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-> ErrorResponse
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-> YesodApp
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safeEh log' er req = do
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liftIO $ log' $(qLocation >>= liftLoc) "yesod-core" LevelError
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$ toLogStr $ "Error handler errored out: " ++ show er
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return $ YRPlain
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H.status500
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[]
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typePlain
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(toContent ("Internal Server Error" :: S.ByteString))
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(reqSession req)
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-- | Run a 'HandlerT' completely outside of Yesod. This
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-- function comes with many caveats and you shouldn't use it
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-- unless you fully understand what it's doing and how it works.
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--
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-- As of now, there's only one reason to use this function at
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-- all: in order to run unit tests of functions inside 'HandlerT'
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-- but that aren't easily testable with a full HTTP request.
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-- Even so, it's better to use @wai-test@ or @yesod-test@ instead
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-- of using this function.
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--
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-- This function will create a fake HTTP request (both @wai@'s
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-- 'Request' and @yesod@'s 'Request') and feed it to the
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-- @HandlerT@. The only useful information the @HandlerT@ may
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-- get from the request is the session map, which you must supply
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-- as argument to @runFakeHandler@. All other fields contain
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-- fake information, which means that they can be accessed but
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-- won't have any useful information. The response of the
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-- @HandlerT@ is completely ignored, including changes to the
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-- session, cookies or headers. We only return you the
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-- @HandlerT@'s return value.
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runFakeHandler :: (Yesod site, MonadIO m) =>
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SessionMap
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-> (site -> Logger)
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-> site
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-> HandlerFor site a
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-> m (Either ErrorResponse a)
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runFakeHandler fakeSessionMap logger site handler = liftIO $ do
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ret <- I.newIORef (Left $ InternalError "runFakeHandler: no result")
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maxExpires <- getCurrentMaxExpiresRFC1123
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let handler' = liftIO . I.writeIORef ret . Right =<< handler
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let yapp = runHandler
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RunHandlerEnv
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{ rheRender = yesodRender site $ resolveApproot site fakeWaiRequest
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, rheRoute = Nothing
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, rheSite = site
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, rheUpload = fileUpload site
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, rheLog = messageLoggerSource site $ logger site
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, rheOnError = errHandler
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, rheMaxExpires = maxExpires
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}
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handler'
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errHandler err req = do
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liftIO $ I.writeIORef ret (Left err)
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return $ YRPlain
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H.status500
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[]
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typePlain
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(toContent ("runFakeHandler: errHandler" :: S8.ByteString))
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(reqSession req)
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fakeWaiRequest = Request
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{ requestMethod = "POST"
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, httpVersion = H.http11
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, rawPathInfo = "/runFakeHandler/pathInfo"
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, rawQueryString = ""
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, requestHeaderHost = Nothing
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, requestHeaders = []
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, isSecure = False
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, remoteHost = error "runFakeHandler-remoteHost"
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, pathInfo = ["runFakeHandler", "pathInfo"]
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, queryString = []
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, requestBody = return mempty
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, vault = mempty
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, requestBodyLength = KnownLength 0
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, requestHeaderRange = Nothing
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#if MIN_VERSION_wai(3,2,0)
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, requestHeaderReferer = Nothing
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, requestHeaderUserAgent = Nothing
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#endif
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}
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fakeRequest =
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YesodRequest
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{ reqGetParams = []
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, reqCookies = []
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, reqWaiRequest = fakeWaiRequest
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, reqLangs = []
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, reqToken = Just "NaN" -- not a nonce =)
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, reqAccept = []
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, reqSession = fakeSessionMap
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}
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_ <- runResourceT $ yapp fakeRequest
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I.readIORef ret
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yesodRunner :: (ToTypedContent res, Yesod site)
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=> HandlerFor site res
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-> YesodRunnerEnv site
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-> Maybe (Route site)
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-> Application
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yesodRunner handler' YesodRunnerEnv {..} route req sendResponse
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| Just maxLen <- mmaxLen, KnownLength len <- requestBodyLength req, maxLen < len = sendResponse tooLargeResponse
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| otherwise = do
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let dontSaveSession _ = return []
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(session, saveSession) <- liftIO $
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maybe (return (Map.empty, dontSaveSession)) (`sbLoadSession` req) yreSessionBackend
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maxExpires <- yreGetMaxExpires
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let mkYesodReq = parseWaiRequest req session (isJust yreSessionBackend) mmaxLen
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let yreq =
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case mkYesodReq of
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Left yreq' -> yreq'
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Right needGen -> needGen yreGen
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let ra = resolveApproot yreSite req
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let log' = messageLoggerSource yreSite yreLogger
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-- We set up two environments: the first one has a "safe" error handler
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-- which will never throw an exception. The second one uses the
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-- user-provided errorHandler function. If that errorHandler function
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-- errors out, it will use the safeEh below to recover.
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rheSafe = RunHandlerEnv
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{ rheRender = yesodRender yreSite ra
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, rheRoute = route
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, rheSite = yreSite
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, rheUpload = fileUpload yreSite
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, rheLog = log'
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, rheOnError = safeEh log'
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, rheMaxExpires = maxExpires
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}
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rhe = rheSafe
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{ rheOnError = runHandler rheSafe . errorHandler
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}
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yesodWithInternalState yreSite route $ \is -> do
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yreq' <- yreq
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yar <- runInternalState (runHandler rhe handler yreq') is
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yarToResponse yar saveSession yreq' req is sendResponse
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where
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mmaxLen = maximumContentLength yreSite route
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handler = yesodMiddleware handler'
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yesodRender :: Yesod y
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=> y
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-> ResolvedApproot
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-> Route y
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-> [(Text, Text)] -- ^ url query string
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-> Text
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yesodRender y ar url params =
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decodeUtf8With lenientDecode $ BL.toStrict $ toLazyByteString $
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fromMaybe
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(joinPath y ar ps
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$ params ++ params')
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(urlParamRenderOverride y url params)
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where
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(ps, params') = renderRoute url
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resolveApproot :: Yesod master => master -> Request -> ResolvedApproot
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resolveApproot master req =
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case approot of
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ApprootRelative -> ""
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ApprootStatic t -> t
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ApprootMaster f -> f master
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ApprootRequest f -> f master req
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