Safe Haskell	Safe-Inferred
Language	Haskell2010

Network.HTTP.Semantics.IO

Contents

Reading n bytes
Position read
Filling a buffer

Synopsis

type ReadN = Int -> IO ByteString
defaultReadN :: Socket -> IORef (Maybe ByteString) -> ReadN
type PositionRead = FileOffset -> ByteCount -> Buffer -> IO ByteCount
type PositionReadMaker = FilePath -> IO (PositionRead, Sentinel)
data Sentinel
- = Closer (IO ())
- | Refresher (IO ())
defaultPositionReadMaker :: PositionReadMaker
data Next
- = Next BytesFilled Bool (Maybe DynaNext)
- | CancelNext (Maybe SomeException)
type DynaNext = Buffer -> Int -> IO Next
type BytesFilled = Int
data StreamingChunk
data IsEndOfStream
- = NotEndOfStream
- | EndOfStream (Maybe CleanupStream)
type CleanupStream = IO ()
fillBuilderBodyGetNext :: Builder -> DynaNext
fillFileBodyGetNext :: PositionRead -> FileOffset -> ByteCount -> IO () -> DynaNext
fillStreamBodyGetNext :: IO (Maybe StreamingChunk) -> DynaNext
type TrailersMaker = Maybe ByteString -> IO NextTrailersMaker
defaultTrailersMaker :: TrailersMaker
data NextTrailersMaker
- = NextTrailersMaker TrailersMaker
- | Trailers [Header]
runTrailersMaker :: TrailersMaker -> Buffer -> Int -> IO NextTrailersMaker

Reading n bytes

type ReadN = Int -> IO ByteString Source #

Reading n bytes.

defaultReadN :: Socket -> IORef (Maybe ByteString) -> ReadN Source #

Naive implementation for readN.

NOTE: This function is intended to be used by a single thread only. (It is probably quite rare anyway to want concurrent reads from the same network socket.)

Position read

type PositionRead = FileOffset -> ByteCount -> Buffer -> IO ByteCount Source #

Position read for files.

type PositionReadMaker = FilePath -> IO (PositionRead, Sentinel) Source #

Making a position read and its closer.

data Sentinel Source #

Constructors

Closer (IO ())	Closing a file resource. Its refresher is automatiaclly generated by the internal timer.
Refresher (IO ())	Refreshing a file resource while reading. Closing the file must be done by its own timer or something.

defaultPositionReadMaker :: PositionReadMaker Source #

Position read based on Handle.

Filling a buffer

data Next Source #

Constructors

Next BytesFilled Bool (Maybe DynaNext)
CancelNext (Maybe SomeException)

type DynaNext Source #

Arguments

= Buffer

Write buffer

-> Int

Maximum number of bytes we are allowed to write

In http2, this maximum will be set to the space left in the write buffer. Implicitly this also means that this maximum cannot exceed the maximum size of a HTTP2 frame, since in http2 the size of the write buffer is also used to set SETTINGS_MAX_FRAME_SIZE (see confBufferSize).

-> IO Next

Information on the data written, and on how to continue if not all data was written

Write part of a streaming response to the write buffer

In http2 this will be used to construct a single HTTP2 DATA frame (see discussion of the maximum number of bytes, below).

type BytesFilled = Int Source #

data StreamingChunk Source #

Constructors

StreamingFinished (Maybe CleanupStream)	Indicate that the stream is finished
StreamingCancelled (Maybe SomeException)	Indicate that the stream is cancelled
StreamingFlush	Flush the stream This will cause the write buffer to be written to the network socket, without waiting for more data.
StreamingBuilder Builder IsEndOfStream	Construct a DATA frame, optionally terminating the stream

data IsEndOfStream Source #

Constructors

NotEndOfStream

The stream is not yet terminated

EndOfStream (Maybe CleanupStream)

The stream is terminated

In addition to indicating that the stream is terminated, we can also specify an optional Cleanup handler to be run.

type CleanupStream = IO () Source #

Action to run prior to terminating the stream

fillBuilderBodyGetNext :: Builder -> DynaNext Source #

fillFileBodyGetNext :: PositionRead -> FileOffset -> ByteCount -> IO () -> DynaNext Source #

fillStreamBodyGetNext :: IO (Maybe StreamingChunk) -> DynaNext Source #

type TrailersMaker = Maybe ByteString -> IO NextTrailersMaker Source #

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

defaultTrailersMaker :: TrailersMaker Source #

TrailersMake to create no trailers.

data NextTrailersMaker Source #

Either the next trailers maker or final trailers.

Constructors

NextTrailersMaker TrailersMaker
Trailers [Header]

runTrailersMaker :: TrailersMaker -> Buffer -> Int -> IO NextTrailersMaker Source #

Running trailers-maker.

bufferIO buf siz $ \bs -> tlrmkr (Just bs)