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|
--------------------------------------------------------------------
-- |
-- Module : Text.RSS.Import
-- Copyright : (c) Galois, Inc. 2008
-- License : BSD3
--
-- Maintainer: Sigbjorn Finne <sof@galois.com>
-- Stability : provisional
-- Description: Converting from XML to RSS
--
--------------------------------------------------------------------
module Text.RSS.Import where
import Text.RSS.Syntax
import Text.RSS1.Utils ( dcNS, dcPrefix )
import Text.XML.Light as XML
import Data.Maybe (listToMaybe, mapMaybe)
import Data.Char (isSpace )
import Control.Monad (guard,mplus)
pNodes :: String -> [XML.Element] -> [XML.Element]
pNodes x es = filter ((qualName x ==) . elName) es
pQNodes :: QName -> [XML.Element] -> [XML.Element]
pQNodes x es = filter ((x==) . elName) es
pNode :: String -> [XML.Element] -> Maybe XML.Element
pNode x es = listToMaybe (pNodes x es)
pQNode :: QName -> [XML.Element] -> Maybe XML.Element
pQNode x es = listToMaybe (pQNodes x es)
pLeaf :: String -> [XML.Element] -> Maybe String
pLeaf x es = strContent `fmap` pNode x es
pQLeaf :: QName -> [XML.Element] -> Maybe String
pQLeaf x es = strContent `fmap` (pQNode x es)
pAttr :: String -> XML.Element -> Maybe String
pAttr x e = lookup (qualName x) [ (k,v) | Attr k v <- elAttribs e ]
pMany :: String -> (XML.Element -> Maybe a) -> [XML.Element] -> [a]
pMany p f es = mapMaybe f (pNodes p es)
children :: XML.Element -> [XML.Element]
children e = onlyElems (elContent e)
qualName :: String -> QName
qualName x = QName{qName=x,qURI=Nothing,qPrefix=Nothing}
dcName :: String -> QName
dcName x = blank_name{qName=x,qURI=dcNS,qPrefix=dcPrefix}
elementToRSS :: XML.Element -> Maybe RSS
elementToRSS e = do
guard (elName e == qualName "rss")
let es = children e
let as = elAttribs e
v <- pAttr "version" e
ch <- pNode "channel" es >>= elementToChannel
return RSS
{ rssVersion = v
, rssAttrs = filter (\ a -> not (qName (attrKey a) `elem` known_attrs)) as
, rssChannel = ch
, rssOther = filter (\ e1 -> elName e1 /= qualName "channel") es
}
where
known_attrs = ["version"]
elementToChannel :: XML.Element -> Maybe RSSChannel
elementToChannel e = do
guard (elName e == qualName "channel")
let es = children e
title <- pLeaf "title" es
link <- pLeaf "link" es
desc <- pLeaf "description" es
return RSSChannel
{ rssTitle = title
, rssLink = link
, rssDescription = desc
, rssItems = pMany "item" elementToItem es
, rssLanguage = pLeaf "language" es `mplus` pQLeaf (dcName "lang") es
, rssCopyright = pLeaf "copyright" es
, rssEditor = pLeaf "managingEditor" es `mplus` pQLeaf (dcName "creator") es
, rssWebMaster = pLeaf "webMaster" es
, rssPubDate = pLeaf "pubDate" es `mplus` pQLeaf (dcName "date") es
, rssLastUpdate = pLeaf "lastBuildDate" es `mplus` pQLeaf (dcName "date") es
, rssCategories = pMany "category" elementToCategory es
, rssGenerator = pLeaf "generator" es `mplus` pQLeaf (dcName "source") es
, rssDocs = pLeaf "docs" es
, rssCloud = pNode "cloud" es >>= elementToCloud
, rssTTL = pLeaf "ttl" es >>= readInt
, rssImage = pNode "image" es >>= elementToImage
, rssRating = pLeaf "rating" es
, rssTextInput = pNode "textInput" es >>= elementToTextInput
, rssSkipHours = pNode "skipHours" es >>= elementToSkipHours
, rssSkipDays = pNode "skipDays" es >>= elementToSkipDays
, rssChannelOther = filter (\ e1 -> not (elName e1 `elem` known_channel_elts)) es
}
where
known_channel_elts = map qualName
[ "title", "link", "description"
, "item", "language", "copyright"
, "managingEditor", "webMaster"
, "pubDate", "lastBuildDate"
, "category", "generator", "docs"
, "cloud", "ttl", "image"
, "rating", "textInput"
, "skipHours", "skipDays"
]
elementToImage :: XML.Element -> Maybe RSSImage
elementToImage e = do
guard (elName e == qualName "image")
let es = children e
url <- pLeaf "url" es
title <- pLeaf "title" es
link <- pLeaf "link" es
return RSSImage
{ rssImageURL = url
, rssImageTitle = title
, rssImageLink = link
, rssImageWidth = pLeaf "width" es >>= readInt
, rssImageHeight = pLeaf "height" es >>= readInt
, rssImageDesc = pLeaf "description" es
, rssImageOther = filter (\ e1 -> not (elName e1 `elem` known_image_elts)) es
}
where
known_image_elts = map qualName
[ "url", "title", "link"
, "width", "height", "description"
]
elementToCategory :: XML.Element -> Maybe RSSCategory
elementToCategory e = do
guard (elName e == qualName "category")
let as = elAttribs e
return RSSCategory
{ rssCategoryDomain = pAttr "domain" e
, rssCategoryAttrs = filter (\ a -> not (qName (attrKey a) `elem` known_attrs)) as
, rssCategoryValue = strContent e
}
where
known_attrs = ["domain"]
elementToCloud :: XML.Element -> Maybe RSSCloud
elementToCloud e = do
guard (elName e == qualName "cloud")
let as = elAttribs e
return RSSCloud
{ rssCloudDomain = pAttr "domain" e
, rssCloudPort = pAttr "port" e
, rssCloudPath = pAttr "path" e
, rssCloudRegister = pAttr "register" e
, rssCloudProtocol = pAttr "protocol" e
, rssCloudAttrs = filter (\ a -> not (qName (attrKey a) `elem` known_attrs)) as
}
where
known_attrs = [ "domain", "port", "path", "register", "protocol" ]
elementToItem :: XML.Element -> Maybe RSSItem
elementToItem e = do
guard (elName e == qualName "item")
let es = children e
return RSSItem
{ rssItemTitle = pLeaf "title" es
, rssItemLink = pLeaf "link" es
, rssItemDescription = pLeaf "description" es
, rssItemAuthor = pLeaf "author" es `mplus` pQLeaf (dcName "creator") es
, rssItemCategories = pMany "category" elementToCategory es
, rssItemComments = pLeaf "comments" es
, rssItemEnclosure = pNode "enclosure" es >>= elementToEnclosure
, rssItemGuid = pNode "guid" es >>= elementToGuid
, rssItemPubDate = pLeaf "pubDate" es `mplus` pQLeaf (dcName "date") es
, rssItemSource = pNode "source" es >>= elementToSource
, rssItemAttrs = elAttribs e
, rssItemOther = filter (\ e1 -> not (elName e1 `elem` known_item_elts)) es
}
where
known_item_elts = map qualName
[ "title", "link", "description"
, "author", "category", "comments"
, "enclosure", "guid", "pubDate"
, "source"
]
elementToSource :: XML.Element -> Maybe RSSSource
elementToSource e = do
guard (elName e == qualName "source")
let as = elAttribs e
url <- pAttr "url" e
return RSSSource
{ rssSourceURL = url
, rssSourceAttrs = filter (\ a -> not (qName (attrKey a) `elem` known_attrs)) as
, rssSourceTitle = strContent e
}
where
known_attrs = [ "url" ]
elementToEnclosure :: XML.Element -> Maybe RSSEnclosure
elementToEnclosure e = do
guard (elName e == qualName "enclosure")
let as = elAttribs e
url <- pAttr "url" e
ty <- pAttr "type" e
len <- pAttr "length" e >>= readInt
return RSSEnclosure
{ rssEnclosureURL = url
, rssEnclosureType = ty
, rssEnclosureLength = len
, rssEnclosureAttrs = filter (\ a -> not (qName (attrKey a) `elem` known_attrs)) as
}
where
known_attrs = [ "url", "type", "length" ]
elementToGuid :: XML.Element -> Maybe RSSGuid
elementToGuid e = do
guard (elName e == qualName "guid")
let as = elAttribs e
return RSSGuid
{ rssGuidPermanentURL = pAttr "isPermaLink" e >>= readBool
, rssGuidAttrs = filter (\ a -> not (qName (attrKey a) `elem` known_attrs)) as
, rssGuidValue = strContent e
}
where
known_attrs = ["isPermaLink"]
elementToTextInput :: XML.Element -> Maybe RSSTextInput
elementToTextInput e = do
guard (elName e == qualName "textInput")
let es = children e
title <- pLeaf "title" es
desc <- pLeaf "description" es
name <- pLeaf "name" es
link <- pLeaf "link" es
return RSSTextInput
{ rssTextInputTitle = title
, rssTextInputDesc = desc
, rssTextInputName = name
, rssTextInputLink = link
, rssTextInputAttrs = elAttribs e
, rssTextInputOther = filter (\ e1 -> not (elName e1 `elem` known_ti_elts)) es
}
where
known_ti_elts = map qualName
["title", "description", "name", "link"]
elementToSkipHours :: XML.Element -> Maybe [Integer]
elementToSkipHours e = do
guard (elName e == qualName "skipHours")
-- don't bother checking that this is below limit ( <= 24)
return (pMany "hour" (readInt.strContent) (children e))
elementToSkipDays :: XML.Element -> Maybe [String]
elementToSkipDays e = do
guard (elName e == qualName "skipDays")
-- don't bother checking that this is below limit ( <= 7)
return (pMany "day" (return . strContent) (children e))
----
readInt :: String -> Maybe Integer
readInt s =
case reads s of
((x,_):_) -> Just x
_ -> Nothing
readBool :: String -> Maybe Bool
readBool s =
case dropWhile isSpace s of
't':'r':'u':'e':_ -> Just True
'f':'a':'l':'s':'e':_ -> Just False
_ -> Nothing
|
