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{- hpodder component
Copyright (C) 2006 John Goerzen <jgoerzen@complete.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : FeedParser
Copyright : Copyright (C) 2006 John Goerzen
License : GNU GPL, version 2 or above
Maintainer : John Goerzen <jgoerzen@complete.org>
Stability : provisional
Portability: portable
Written by John Goerzen, jgoerzen\@complete.org
-}
module FeedParser where
import Types
import Text.XML.HaXml
import Text.XML.HaXml.Parse
import Utils
import Data.Maybe.Utils
import Data.Char
import Data.Either.Utils
import Data.List
data Item = Item {itemtitle :: String,
itemguid :: Maybe String,
enclosureurl :: String,
enclosuretype :: String,
enclosurelength :: String
}
deriving (Eq, Show, Read)
data Feed = Feed {channeltitle :: String,
items :: [Item]}
deriving (Eq, Show, Read)
item2ep pc item =
Episode {podcast = pc, epid = 0,
eptitle = sanitize_basic (itemtitle item),
epurl = sanitize_basic (enclosureurl item),
epguid = fmap sanitize_basic (itemguid item),
eptype = sanitize_basic (enclosuretype item), epstatus = Pending,
eplength = case reads . sanitize_basic . enclosurelength $ item of
[] -> 0
[(x, [])] -> x
_ -> 0,
epfirstattempt = Nothing,
eplastattempt = Nothing,
epfailedattempts = 0}
parse :: FilePath -> String -> IO (Either String Feed)
parse fp name =
do c <- readFile fp
case xmlParse' name (unifrob c) of
Left x -> return (Left x)
Right y ->
do let doc = getContent y
let title = getTitle doc
let feeditems = getEnclosures doc
return $ Right $
(Feed {channeltitle = title, items = feeditems})
where getContent (Document _ _ e _) = CElem e
unifrob ('\xef':'\xbb':'\xbf':x) = x -- Strip off unicode BOM
unifrob x = x
unesc = xmlUnEscape stdXmlEscaper
getTitle doc = forceEither $ strofm "title" (channel doc)
getEnclosures doc =
concat . map procitem $ item doc
where procitem i = map (procenclosure title guid) enclosure
where title = case strofm "title" [i] of
Left x -> "Untitled"
Right x -> x
guid = case strofm "guid" [i] of
Left _ -> Nothing
Right x -> Just x
enclosure = tag "enclosure" `o` children $ i
procenclosure title guid e =
Item {itemtitle = title,
itemguid = guid,
enclosureurl = head0 $ forceMaybe $ stratt "url" e,
enclosuretype = head0 $ case stratt "type" e of
Nothing -> ["application/octet-stream"]
Just x -> x,
enclosurelength = head $ case stratt "length" e of
Nothing -> ["0"]
Just [] -> ["0"]
Just x -> x
}
head0 [] = ""
head0 (x:xs) = x
item = tag "item" `o` children `o` channel
channel =
tag "channel" `o` children `o` tag "rss"
--------------------------------------------------
-- Utilities
--------------------------------------------------
attrofelem :: String -> Content -> Maybe AttValue
attrofelem attrname (CElem inelem) =
case unesc inelem of
Elem name al _ -> lookup attrname al
attrofelem _ _ =
error "attrofelem: called on something other than a CElem"
stratt :: String -> Content -> Maybe [String]
stratt attrname content =
case attrofelem attrname content of
Just (AttValue x) -> Just (concat . map mapfunc $ x)
Nothing -> Nothing
where mapfunc (Left x) = [x]
mapfunc (Right _) = []
-- Finds the literal children of the named tag, and returns it/them
tagof :: String -> CFilter
tagof x = keep /> tag x -- /> txt
-- Retruns the literal string that tagof would find
strof :: String -> Content -> String
strof x y = forceEither $ strof_either x y
strof_either :: String -> Content -> Either String String
strof_either x y =
case tagof x $ y of
[CElem elem] -> Right $ verbatim $ tag x /> txt $ CElem (unesc elem)
z -> Left $ "strof: expecting CElem in " ++ x ++ ", got "
++ verbatim z ++ " at " ++ verbatim y
strofm x y =
if length errors /= 0
then Left errors
else Right (concat plainlist)
where mapped = map (strof_either x) $ y
(errors, plainlist) = conveithers mapped
isright (Left _) = False
isright (Right _) = True
conveithers :: [Either a b] -> ([a], [b])
conveithers inp = worker inp ([], [])
where worker [] y = y
worker (Left x:xs) (lefts, rights) =
worker xs (x:lefts, rights)
worker (Right x:xs) (lefts, rights) =
worker xs (lefts, x:rights)
|
