HTTP-4000.2.0: A library for client-side HTTP

Portabilitynon-portable (not tested)
MaintainerSigbjorn Finne <>



In order to give the user freedom in how request and response content is represented, a sufficiently abstract representation is needed of these internally. The Network.BufferType module provides this, defining the BufferType class and its ad-hoc representation of buffer operations via the BufferOp record.

This module provides definitions for the standard buffer types that the package supports, i.e., for String and ByteString (strict and lazy.)



class BufferType bufType whereSource

The BufferType class encodes, in a mixed-mode way, the interface that the library requires to operate over data embedded in HTTP requests and responses. That is, we use explicit dictionaries for the operations, but overload the name of the dicts themselves.


bufferOps :: BufferOp bufTypeSource

data BufferOp a Source

BufferOp encodes the I/O operations of the underlying buffer over a Handle in an (explicit) dictionary type. May not be needed, but gives us flexibility in explicit overriding and wrapping up of these methods.

Along with IO operations is an ad-hoc collection of functions for working with these abstract buffers, as needed by the internals of the code that processes requests and responses.

We supply three default BufferOp values, for String along with the strict and lazy versions of ByteString. To add others, provide BufferOp definitions for




buf_hGet :: Handle -> Int -> IO a
buf_hGetContents :: Handle -> IO a
buf_hPut :: Handle -> a -> IO ()
buf_hGetLine :: Handle -> IO a
buf_empty :: a
buf_append :: a -> a -> a
buf_concat :: [a] -> a
buf_fromStr :: String -> a
buf_toStr :: a -> String
buf_snoc :: a -> Word8 -> a
buf_splitAt :: Int -> a -> (a, a)
buf_span :: (Char -> Bool) -> a -> (a, a)
buf_isLineTerm :: a -> Bool
buf_isEmpty :: a -> Bool


Eq (BufferOp a) 

strictBufferOp :: BufferOp ByteStringSource

strictBufferOp is the BufferOp definition over ByteStrings, the non-lazy kind.

lazyBufferOp :: BufferOp ByteStringSource

lazyBufferOp is the BufferOp definition over ByteStrings, the non-strict kind.

stringBufferOp :: BufferOp StringSource

stringBufferOp is the BufferOp definition over Strings. It is defined in terms of strictBufferOp operations, unpacking/converting to String when needed.