HTTP-4000.2.0: A library for client-side HTTP

Portabilitynon-portable (not tested)
MaintainerSigbjorn Finne <>




Definitions of Request and Response types along with functions for normalizing them. It is assumed to be an internal module; user code should, if possible, import Network.HTTP to access the functionality that this module provides.

Additionally, the module exports internal functions for working with URLs, and for handling the processing of requests and responses coming back.




data Request a Source

An HTTP Request. The Show instance of this type is used for message serialisation, which means no body data is output.




rqURI :: URI

might need changing in future 1) to support * uri in OPTIONS request 2) transparent support for both relative & absolute uris, although this should already work (leave scheme & host parts empty).

rqMethod :: RequestMethod
rqHeaders :: [Header]
rqBody :: a


data Response a Source

An HTTP Response. The Show instance of this type is used for message serialisation, which means no body data is output, additionally the output will show an HTTP version of 1.1 instead of the actual version returned by a server.




data RequestMethod Source

The HTTP request method, to be used in the Request object. We are missing a few of the stranger methods, but these are not really necessary until we add full TLS.

URL Encoding

URI authority parsing

parseURIAuthority :: String -> Maybe URIAuthoritySource

Parse the authority part of a URL.

 RFC 1732, section 3.1:

  Some or all of the parts "<user>:<password>@", ":<password>",
  ":<port>", and "/<url-path>" may be excluded.

type ResponseData = (ResponseCode, String, [Header])Source

ResponseData contains the head of a response payload; HTTP response code, accompanying text description + header fields.

type ResponseCode = (Int, Int, Int)Source

For easy pattern matching, HTTP response codes xyz are represented as (x,y,z).

type RequestData = (RequestMethod, URI, [Header])Source

RequestData contains the head of a HTTP request; method, its URL along with the auxillary/supporting header data.

data NormalizeRequestOptions ty Source

NormalizeRequestOptions brings together the various defaulting/normalization options over Requests. Use defaultNormalizeRequestOptions for the standard selection of option

type RequestNormalizer ty = NormalizeRequestOptions ty -> Request ty -> Request tySource

RequestNormalizer is the shape of a (pure) function that rewrites a request into some normalized form.

normalizeRequest :: NormalizeRequestOptions ty -> Request ty -> Request tySource

normalizeRequest opts req is the entry point to use to normalize your request prior to transmission (or other use.) Normalization is controlled via the NormalizeRequestOptions record.

getAuth :: Monad m => Request ty -> m URIAuthoritySource

getAuth req fishes out the authority portion of the URL in a request's Host header.

linearTransfer :: (Int -> IO (Result a)) -> Int -> IO (Result ([Header], a))Source

Used when we know exactly how many bytes to expect.

hopefulTransfer :: BufferOp a -> IO (Result a) -> [a] -> IO (Result ([Header], a))Source

Used when nothing about data is known, Unfortunately waiting for a socket closure causes bad behaviour. Here we just take data once and give up the rest.

chunkedTransfer :: BufferOp a -> IO (Result a) -> (Int -> IO (Result a)) -> IO (Result ([Header], a))Source

A necessary feature of HTTP/1.1 Also the only transfer variety likely to return any footers.

uglyDeathTransfer :: String -> IO (Result ([Header], a))Source

Maybe in the future we will have a sensible thing to do here, at that time we might want to change the name.

readTillEmpty1 :: BufferOp a -> IO (Result a) -> IO (Result [a])Source

Remove leading crlfs then call readTillEmpty2 (not required by RFC)

readTillEmpty2 :: BufferOp a -> IO (Result a) -> [a] -> IO (Result [a])Source

Read lines until an empty line (CRLF), also accepts a connection close as end of input, which is not an HTTP/1.1 compliant thing to do - so probably indicates an error condition.

mkRequest :: BufferType ty => RequestMethod -> URI -> Request tySource

'mkRequest method uri' constructs a well formed request for the given HTTP method and URI. It does not normalize the URI for the request _nor_ add the required Host: header. That is done either explicitly by the user or when requests are normalized prior to transmission.

defaultUserAgent :: StringSource

A default user agent string. The string is "haskell-HTTP/$version" where $version is the version of this HTTP package.

httpPackageVersion :: StringSource

The version of this HTTP package as a string, e.g. "4000.1.2". This may be useful to include in a user agent string so that you can determine from server logs what version of this package HTTP clients are using. This can be useful for tracking down HTTP compatibility quirks.

catchIO :: IO a -> (IOException -> IO a) -> IO aSource

catchIO a h handles IO action exceptions throughout codebase; version-specific tweaks better go here.

catchIO_ :: IO a -> IO a -> IO aSource

getRequestVersion :: Request a -> Maybe StringSource

getRequestVersion req returns the HTTP protocol version of the request req. If Nothing, the default httpVersion can be assumed.

getResponseVersion :: Response a -> Maybe StringSource

getResponseVersion rsp returns the HTTP protocol version of the response rsp. If Nothing, the default httpVersion can be assumed.

setRequestVersion :: String -> Request a -> Request aSource

setRequestVersion v req returns a new request, identical to req, but with its HTTP version set to v.

setResponseVersion :: String -> Response a -> Response aSource

setResponseVersion v rsp returns a new response, identical to rsp, but with its HTTP version set to v.