152 lines
4.2 KiB
Haskell
152 lines
4.2 KiB
Haskell
---------------------------------------------------------
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--
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-- Module : Yesod.Request
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-- Copyright : Michael Snoyman
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-- License : BSD3
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--
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-- Maintainer : Michael Snoyman <michael@snoyman.com>
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-- Stability : Stable
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-- Portability : portable
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--
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-- | Provides a parsed version of the raw 'W.Request' data.
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--
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---------------------------------------------------------
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module Yesod.Request
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(
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-- * Request datatype
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RequestBodyContents
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, Request (..)
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, RequestReader (..)
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, FileInfo (..)
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-- * Convenience functions
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, waiRequest
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, languages
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-- * Lookup parameters
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, lookupGetParam
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, lookupPostParam
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, lookupCookie
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, lookupFile
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-- ** Multi-lookup
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, lookupGetParams
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, lookupPostParams
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, lookupCookies
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, lookupFiles
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-- * Parameter type synonyms
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, ParamName
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, ParamValue
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, ParamError
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) where
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import qualified Network.Wai as W
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import qualified Data.ByteString.Lazy as BL
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import Control.Monad.IO.Class
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import Control.Monad (liftM)
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import Control.Monad.Instances () -- I'm missing the instance Monad ((->) r
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import Data.Maybe (listToMaybe)
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type ParamName = String
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type ParamValue = String
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type ParamError = String
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-- FIXME perhaps remove RequestReader typeclass, include Request datatype in Handler
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-- | The reader monad specialized for 'Request'.
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class Monad m => RequestReader m where
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getRequest :: m Request
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runRequestBody :: m RequestBodyContents
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-- | Get the list of supported languages supplied by the user.
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--
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-- Languages are determined based on the following three (in descending order
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-- of preference):
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--
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-- * The _LANG get parameter.
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--
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-- * The _LANG cookie.
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--
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-- * The _LANG user session variable.
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--
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-- * Accept-Language HTTP header.
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--
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-- This is handled by parseWaiRequest (not exposed).
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languages :: RequestReader m => m [String]
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languages = reqLangs `liftM` getRequest
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-- | Get the request\'s 'W.Request' value.
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waiRequest :: RequestReader m => m W.Request
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waiRequest = reqWaiRequest `liftM` getRequest
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-- | A tuple containing both the POST parameters and submitted files.
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type RequestBodyContents =
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( [(ParamName, ParamValue)]
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, [(ParamName, FileInfo)]
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)
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data FileInfo = FileInfo
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{ fileName :: String
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, fileContentType :: String
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, fileContent :: BL.ByteString
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}
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deriving (Eq, Show)
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-- | The parsed request information.
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data Request = Request
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{ reqGetParams :: [(ParamName, ParamValue)]
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, reqCookies :: [(ParamName, ParamValue)]
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, reqWaiRequest :: W.Request
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-- | Languages which the client supports.
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, reqLangs :: [String]
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-- | A random, session-specific nonce used to prevent CSRF attacks.
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, reqNonce :: Maybe String
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}
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lookup' :: Eq a => a -> [(a, b)] -> [b]
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lookup' a = map snd . filter (\x -> a == fst x)
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-- | Lookup for GET parameters.
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lookupGetParams :: RequestReader m => ParamName -> m [ParamValue]
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lookupGetParams pn = do
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rr <- getRequest
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return $ lookup' pn $ reqGetParams rr
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-- | Lookup for GET parameters.
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lookupGetParam :: RequestReader m => ParamName -> m (Maybe ParamValue)
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lookupGetParam = liftM listToMaybe . lookupGetParams
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-- | Lookup for POST parameters.
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lookupPostParams :: RequestReader m
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=> ParamName
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-> m [ParamValue]
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lookupPostParams pn = do
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(pp, _) <- runRequestBody
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return $ lookup' pn pp
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lookupPostParam :: (MonadIO m, RequestReader m)
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=> ParamName
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-> m (Maybe ParamValue)
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lookupPostParam = liftM listToMaybe . lookupPostParams
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-- | Lookup for POSTed files.
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lookupFile :: (MonadIO m, RequestReader m)
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=> ParamName
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-> m (Maybe FileInfo)
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lookupFile = liftM listToMaybe . lookupFiles
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-- | Lookup for POSTed files.
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lookupFiles :: RequestReader m
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=> ParamName
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-> m [FileInfo]
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lookupFiles pn = do
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(_, files) <- runRequestBody
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return $ lookup' pn files
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-- | Lookup for cookie data.
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lookupCookie :: RequestReader m => ParamName -> m (Maybe ParamValue)
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lookupCookie = liftM listToMaybe . lookupCookies
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-- | Lookup for cookie data.
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lookupCookies :: RequestReader m => ParamName -> m [ParamValue]
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lookupCookies pn = do
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rr <- getRequest
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return $ lookup' pn $ reqCookies rr
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