module Hakyll.Web.Urls
( withUrls
, toUrl
, toSiteRoot
, isExternal
) where
import Data.List (isPrefixOf)
import System.FilePath (splitPath, takeDirectory, joinPath)
import qualified Data.Set as S
import Text.HTML.TagSoup (Tag (..), renderTags, parseTags)
withUrls :: (String -> String) -> String -> String
withUrls f = renderTags . map tag . parseTags
where
tag (TagOpen s a) = TagOpen s $ map attr a
tag x = x
attr (k, v) = (k, if k `S.member` refs then f v else v)
refs = S.fromList ["src", "href"]
toUrl :: FilePath -> String
toUrl ('/' : xs) = '/' : xs
toUrl url = '/' : url
toSiteRoot :: String -> String
toSiteRoot = emptyException . joinPath . map parent
. filter relevant . splitPath . takeDirectory
where
parent = const ".."
emptyException [] = "."
emptyException x = x
relevant "." = False
relevant "/" = False
relevant _ = True
isExternal :: String -> Bool
isExternal url = any (flip isPrefixOf url) ["http://", "https://"]