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module Network.HTTP.Semantics.Trailer where
import Network.ByteOrder
import qualified Network.HTTP.Types as H
-- | Trailers maker. A chunks of the response body is passed
-- with 'Just'. The maker should update internal state
-- with the 'ByteString' and return the next trailers maker.
-- When response body reaches its end,
-- 'Nothing' is passed and the maker should generate
-- trailers. An example:
--
-- > {-# LANGUAGE BangPatterns #-}
-- > import Data.ByteString (ByteString)
-- > import qualified Data.ByteString.Char8 as C8
-- > import Crypto.Hash (Context, SHA1) -- cryptonite
-- > import qualified Crypto.Hash as CH
-- >
-- > -- Strictness is important for Context.
-- > trailersMaker :: Context SHA1 -> Maybe ByteString -> IO NextTrailersMaker
-- > trailersMaker ctx Nothing = return $ Trailers [("X-SHA1", sha1)]
-- > where
-- > !sha1 = C8.pack $ show $ CH.hashFinalize ctx
-- > trailersMaker ctx (Just bs) = return $ NextTrailersMaker $ trailersMaker ctx'
-- > where
-- > !ctx' = CH.hashUpdate ctx bs
--
-- Usage example:
--
-- > let h2rsp = responseFile ...
-- > maker = trailersMaker (CH.hashInit :: Context SHA1)
-- > h2rsp' = setResponseTrailersMaker h2rsp maker
type TrailersMaker = Maybe ByteString -> IO NextTrailersMaker
-- | TrailersMake to create no trailers.
defaultTrailersMaker :: TrailersMaker
defaultTrailersMaker Nothing = return $ Trailers []
defaultTrailersMaker _ = return $ NextTrailersMaker defaultTrailersMaker
-- | Either the next trailers maker or final trailers.
data NextTrailersMaker
= NextTrailersMaker TrailersMaker
| Trailers [H.Header]
----------------------------------------------------------------
-- | Running trailers-maker.
--
-- > bufferIO buf siz $ \bs -> tlrmkr (Just bs)
runTrailersMaker :: TrailersMaker -> Buffer -> Int -> IO NextTrailersMaker
runTrailersMaker tlrmkr buf siz = bufferIO buf siz $ \bs -> tlrmkr (Just bs)
|
