HTTP-4000.0.9: A library for client-side HTTPContentsIndex
Network.HTTP.Headers
Portabilitynon-portable (not tested)
Stabilityexperimental
MaintainerSigbjorn Finne <sigbjorn.finne@gmail.com>
Description
This module provides the data types for representing HTTP headers, and operations for looking up header values and working with sequences of header values in Requests and Responses. To avoid having to provide separate set of operations for doing so, we introduce a type class HasHeaders to facilitate writing such processing using overloading instead.
Synopsis
class HasHeaders x where
getHeaders :: x -> [Header]
setHeaders :: x -> [Header] -> x
data Header = Header HeaderName String
mkHeader :: HeaderName -> String -> Header
hdrName :: Header -> HeaderName
hdrValue :: Header -> String
data HeaderName
= HdrCacheControl
| HdrConnection
| HdrDate
| HdrPragma
| HdrTransferEncoding
| HdrUpgrade
| HdrVia
| HdrAccept
| HdrAcceptCharset
| HdrAcceptEncoding
| HdrAcceptLanguage
| HdrAuthorization
| HdrCookie
| HdrExpect
| HdrFrom
| HdrHost
| HdrIfModifiedSince
| HdrIfMatch
| HdrIfNoneMatch
| HdrIfRange
| HdrIfUnmodifiedSince
| HdrMaxForwards
| HdrProxyAuthorization
| HdrRange
| HdrReferer
| HdrUserAgent
| HdrAge
| HdrLocation
| HdrProxyAuthenticate
| HdrPublic
| HdrRetryAfter
| HdrServer
| HdrSetCookie
| HdrTE
| HdrTrailer
| HdrVary
| HdrWarning
| HdrWWWAuthenticate
| HdrAllow
| HdrContentBase
| HdrContentEncoding
| HdrContentLanguage
| HdrContentLength
| HdrContentLocation
| HdrContentMD5
| HdrContentRange
| HdrContentType
| HdrETag
| HdrExpires
| HdrLastModified
| HdrContentTransferEncoding
| HdrCustom String
insertHeader :: HasHeaders a => HeaderSetter a
insertHeaderIfMissing :: HasHeaders a => HeaderSetter a
insertHeaders :: HasHeaders a => [Header] -> a -> a
retrieveHeaders :: HasHeaders a => HeaderName -> a -> [Header]
replaceHeader :: HasHeaders a => HeaderSetter a
findHeader :: HasHeaders a => HeaderName -> a -> Maybe String
lookupHeader :: HeaderName -> [Header] -> Maybe String
parseHeader :: String -> Result Header
parseHeaders :: [String] -> Result [Header]
headerMap :: [(String, HeaderName)]
type HeaderSetter a = HeaderName -> String -> a -> a
Documentation
class HasHeaders x where
HasHeaders is a type class for types containing HTTP headers, allowing you to write overloaded header manipulation functions for both Request and Response data types, for instance.
Methods
getHeaders :: x -> [Header]
setHeaders :: x -> [Header] -> x
show/hide Instances
data Header
The Header data type pairs header names & values.
Constructors
Header HeaderName String
show/hide Instances
mkHeader :: HeaderName -> String -> Header
Header constructor as a function, hiding above rep.
hdrName :: Header -> HeaderName
hdrValue :: Header -> String
data HeaderName

HTTP HeaderName type, a Haskell data constructor for each specification-defined header, prefixed with Hdr and CamelCased, (i.e., eliding the - in the process.) Should you require using a custom header, there's the HdrCustom constructor which takes a String argument.

Encoding HTTP header names differently, as Strings perhaps, is an equally fine choice..no decidedly clear winner, but let's stick with data constructors here.

Constructors
HdrCacheControl
HdrConnection
HdrDate
HdrPragma
HdrTransferEncoding
HdrUpgrade
HdrVia
HdrAccept
HdrAcceptCharset
HdrAcceptEncoding
HdrAcceptLanguage
HdrAuthorization
HdrCookie
HdrExpect
HdrFrom
HdrHost
HdrIfModifiedSince
HdrIfMatch
HdrIfNoneMatch
HdrIfRange
HdrIfUnmodifiedSince
HdrMaxForwards
HdrProxyAuthorization
HdrRange
HdrReferer
HdrUserAgent
HdrAge
HdrLocation
HdrProxyAuthenticate
HdrPublic
HdrRetryAfter
HdrServer
HdrSetCookie
HdrTE
HdrTrailer
HdrVary
HdrWarning
HdrWWWAuthenticate
HdrAllow
HdrContentBase
HdrContentEncoding
HdrContentLanguage
HdrContentLength
HdrContentLocation
HdrContentMD5
HdrContentRange
HdrContentType
HdrETag
HdrExpires
HdrLastModified
HdrContentTransferEncodingMIME entity headers (for sub-parts)
HdrCustom StringAllows for unrecognised or experimental headers.
show/hide Instances
insertHeader :: HasHeaders a => HeaderSetter a
insertHeader hdr val x inserts a header with the given header name and value. Does not check for existing headers with same name, allowing duplicates to be introduce (use replaceHeader if you want to avoid this.)
insertHeaderIfMissing :: HasHeaders a => HeaderSetter a
insertHeaderIfMissing hdr val x adds the new header only if no previous header with name hdr exists in x.
insertHeaders :: HasHeaders a => [Header] -> a -> a
insertHeaders hdrs x appends multiple headers to x's existing set.
retrieveHeaders :: HasHeaders a => HeaderName -> a -> [Header]
retrieveHeaders hdrNm x gets a list of headers with HeaderName hdrNm.
replaceHeader :: HasHeaders a => HeaderSetter a
replaceHeader hdr val o replaces the header hdr with the value val, dropping any existing
findHeader :: HasHeaders a => HeaderName -> a -> Maybe String
findHeader hdrNm x looks up hdrNm in x, returning the first header that matches, if any.
lookupHeader :: HeaderName -> [Header] -> Maybe String
lookupHeader hdr hdrs locates the first header matching hdr in the list hdrs.
parseHeader :: String -> Result Header
parseHeader headerNameAndValueString tries to unscramble a header: value pairing and returning it as a Header.
parseHeaders :: [String] -> Result [Header]
parseHeaders hdrs takes a sequence of strings holding header information and parses them into a set of headers (preserving their order in the input argument.) Handles header values split up over multiple lines.
headerMap :: [(String, HeaderName)]
headerMap is a straight assoc list for translating between header names and values.
type HeaderSetter a = HeaderName -> String -> a -> a
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