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-- | Provides utilities to manipulate URL's
--
module Hakyll.Web.Urls
( withUrls
, toUrl
, toSiteRoot
, isExternal
) where
import Data.List (isPrefixOf)
import Data.Char (toLower)
import System.FilePath (splitPath, takeDirectory, joinPath)
import qualified Data.Set as S
import qualified Text.HTML.TagSoup as TS
-- | Apply a function to each URL on a webpage
--
withUrls :: (String -> String) -> String -> String
withUrls f = renderTags' . map tag . TS.parseTags
where
tag (TS.TagOpen s a) = TS.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"]
-- | Customized TagSoup renderer. (The default TagSoup renderer escape CSS
-- within style tags.)
--
renderTags' :: [TS.Tag String] -> String
renderTags' = TS.renderTagsOptions TS.renderOptions
{ TS.optRawTag = (`elem` ["script", "style"]) . map toLower
, TS.optMinimize = (`elem` ["br", "img"])
}
-- | Convert a filepath to an URL starting from the site root
--
-- Example:
--
-- > toUrl "foo/bar.html"
--
-- Result:
--
-- > "/foo/bar.html"
--
toUrl :: FilePath -> String
toUrl ('/' : xs) = '/' : xs
toUrl url = '/' : url
-- | Get the relative url to the site root, for a given (absolute) 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
-- | Check if an URL links to an external HTTP(S) source
--
isExternal :: String -> Bool
isExternal url = any (flip isPrefixOf url) ["http://", "https://"]
|
