yesod/Yesod/Helpers/AtomFeed.hs
2010-01-25 02:00:08 +02:00

78 lines
2.5 KiB
Haskell

{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
---------------------------------------------------------
--
-- Module : Yesod.Helpers.AtomFeed
-- Copyright : Michael Snoyman
-- License : BSD3
--
-- Maintainer : Michael Snoyman <michael@snoyman.com>
-- Stability : Stable
-- Portability : portable
--
-- Generating atom news feeds.
--
---------------------------------------------------------
module Yesod.Helpers.AtomFeed
( AtomFeed (..)
, AtomFeedEntry (..)
, AtomFeedResponse (..)
, atomFeed
) where
import Yesod
import Data.Time.Clock (UTCTime)
import Web.Encodings (formatW3)
data AtomFeedResponse = AtomFeedResponse AtomFeed Approot
atomFeed :: YesodApproot y => AtomFeed -> Handler y AtomFeedResponse
atomFeed f = do
y <- getYesod
return $ AtomFeedResponse f $ approot y
data AtomFeed = AtomFeed
{ atomTitle :: String
, atomLinkSelf :: Location
, atomLinkHome :: Location
, atomUpdated :: UTCTime
, atomEntries :: [AtomFeedEntry]
}
instance HasReps AtomFeedResponse where
chooseRep = defChooseRep
[ (TypeAtom, return . cs)
]
data AtomFeedEntry = AtomFeedEntry
{ atomEntryLink :: Location
, atomEntryUpdated :: UTCTime
, atomEntryTitle :: String
, atomEntryContent :: Html
}
instance ConvertSuccess AtomFeedResponse Content where
convertSuccess = cs . (cs :: Html -> XmlDoc) . cs
instance ConvertSuccess AtomFeedResponse Html where
convertSuccess (AtomFeedResponse f ar) =
Tag "feed" [("xmlns", "http://www.w3.org/2005/Atom")] $ HtmlList
[ Tag "title" [] $ cs $ atomTitle f
, EmptyTag "link" [ ("rel", "self")
, ("href", showLocation ar $ atomLinkSelf f)
]
, EmptyTag "link" [ ("href", showLocation ar $ atomLinkHome f)
]
, Tag "updated" [] $ cs $ formatW3 $ atomUpdated f
, Tag "id" [] $ cs $ showLocation ar $ atomLinkHome f
, HtmlList $ map cs $ zip (atomEntries f) $ repeat ar
]
instance ConvertSuccess (AtomFeedEntry, Approot) Html where
convertSuccess (e, ar) = Tag "entry" [] $ HtmlList
[ Tag "id" [] $ cs $ showLocation ar $ atomEntryLink e
, EmptyTag "link" [("href", showLocation ar $ atomEntryLink e)]
, Tag "updated" [] $ cs $ formatW3 $ atomEntryUpdated e
, Tag "title" [] $ cs $ atomEntryTitle e
, Tag "content" [("type", "html")] $ cdata $ atomEntryContent e
]