fradrive/src/Handler/Utils/Csv.hs
2019-07-10 19:24:10 +02:00

72 lines
1.9 KiB
Haskell

{-# OPTIONS_GHC -fno-warn-orphans #-}
module Handler.Utils.Csv
( typeCsv, extensionCsv
, decodeCsv
, encodeCsv
, respondCsv, respondCsvDB
, fileSourceCsv
, CsvParseError(..)
, ToNamedRecord(..), FromNamedRecord(..)
, DefaultOrdered(..)
, ToField(..), FromField(..)
) where
import Import
import Data.Csv
import Data.Csv.Conduit
import qualified Data.Conduit.List as C
import qualified Data.Conduit.Combinators as C (sourceLazy)
import qualified Data.Map as Map
deriving instance Typeable CsvParseError
instance Exception CsvParseError
typeCsv :: ContentType
typeCsv = "text/csv"
extensionCsv :: Extension
extensionCsv = fromMaybe "csv" $ listToMaybe [ ext | (ext, mime) <- Map.toList mimeMap, mime == typeCsv ]
decodeCsv :: (MonadThrow m, FromNamedRecord csv) => Conduit ByteString m csv
decodeCsv = transPipe throwExceptT $ fromNamedCsv defaultDecodeOptions
encodeCsv :: ( ToNamedRecord csv
, DefaultOrdered csv
, Monad m
)
=> Conduit csv m ByteString
-- ^ Encode a stream of records
--
-- Currently not streaming
encodeCsv = fmap encodeDefaultOrderedByName (C.foldMap pure) >>= C.sourceLazy
respondCsv :: ( ToNamedRecord csv
, DefaultOrdered csv
)
=> Source (HandlerT site IO) csv
-> HandlerT site IO TypedContent
respondCsv src = respondSource typeCsv $ src .| encodeCsv .| awaitForever sendChunk
respondCsvDB :: ( ToNamedRecord csv
, DefaultOrdered csv
, YesodPersistRunner site
)
=> Source (YesodDB site) csv
-> HandlerT site IO TypedContent
respondCsvDB src = respondSourceDB typeCsv $ src .| encodeCsv .| awaitForever sendChunk
fileSourceCsv :: ( FromNamedRecord csv
, MonadResource m
)
=> FileInfo
-> Source m csv
fileSourceCsv = (.| decodeCsv) . fileSource