Portability | non-portable (not tested) |
---|---|
Stability | experimental |
Maintainer | Ganesh Sittampalam <http@projects.haskell.org> |
Safe Haskell | Safe-Inferred |
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 Request
s and Response
s. 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.
- 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 whereSource
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.
getHeaders :: x -> [Header]Source
setHeaders :: x -> [Header] -> xSource
HasHeaders (Response a) | |
HasHeaders (Request a) |
The Header
data type pairs header names & values.
mkHeader :: HeaderName -> String -> HeaderSource
Header constructor as a function, hiding above rep.
hdrName :: Header -> HeaderNameSource
data HeaderName Source
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.
insertHeader :: HasHeaders a => HeaderSetter aSource
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 aSource
insertHeaderIfMissing hdr val x
adds the new header only if no previous
header with name hdr
exists in x
.
insertHeaders :: HasHeaders a => [Header] -> a -> aSource
insertHeaders hdrs x
appends multiple headers to x
's existing
set.
retrieveHeaders :: HasHeaders a => HeaderName -> a -> [Header]Source
retrieveHeaders hdrNm x
gets a list of headers with HeaderName
hdrNm
.
replaceHeader :: HasHeaders a => HeaderSetter aSource
replaceHeader hdr val o
replaces the header hdr
with the
value val
, dropping any existing
findHeader :: HasHeaders a => HeaderName -> a -> Maybe StringSource
findHeader hdrNm x
looks up hdrNm
in x
, returning the first
header that matches, if any.
lookupHeader :: HeaderName -> [Header] -> Maybe StringSource
lookupHeader hdr hdrs
locates the first header matching hdr
in the
list hdrs
.
parseHeader :: String -> Result HeaderSource
parseHeader headerNameAndValueString
tries to unscramble a
header: value
pairing and returning it as a Header
.
parseHeaders :: [String] -> Result [Header]Source
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)]Source
headerMap
is a straight assoc list for translating between header names
and values.
type HeaderSetter a = HeaderName -> String -> a -> aSource