65 lines
1.7 KiB
Haskell
65 lines
1.7 KiB
Haskell
-- | Provides utilities to manipulate URL's
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--
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module Hakyll.Web.Urls
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( withUrls
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, toUrl
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, toSiteRoot
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, isExternal
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) where
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import Data.List (isPrefixOf)
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import Data.Char (toLower)
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import System.FilePath (splitPath, takeDirectory, joinPath)
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import qualified Data.Set as S
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import qualified Text.HTML.TagSoup as TS
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-- | Apply a function to each URL on a webpage
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--
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withUrls :: (String -> String) -> String -> String
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withUrls f = renderTags' . map tag . TS.parseTags
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where
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tag (TS.TagOpen s a) = TS.TagOpen s $ map attr a
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tag x = x
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attr (k, v) = (k, if k `S.member` refs then f v else v)
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refs = S.fromList ["src", "href"]
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-- | Customized TagSoup renderer. (The default TagSoup renderer escape CSS
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-- within style tags.)
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--
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renderTags' :: [TS.Tag String] -> String
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renderTags' = TS.renderTagsOptions TS.renderOptions
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{ TS.optRawTag = (`elem` ["script", "style"]) . map toLower
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}
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-- | Convert a filepath to an URL starting from the site root
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--
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-- Example:
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--
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-- > toUrl "foo/bar.html"
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--
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-- Result:
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--
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-- > "/foo/bar.html"
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--
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toUrl :: FilePath -> String
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toUrl ('/' : xs) = '/' : xs
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toUrl url = '/' : url
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-- | Get the relative url to the site root, for a given (absolute) url
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--
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toSiteRoot :: String -> String
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toSiteRoot = emptyException . joinPath . map parent
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. filter relevant . splitPath . takeDirectory
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where
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parent = const ".."
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emptyException [] = "."
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emptyException x = x
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relevant "." = False
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relevant "/" = False
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relevant _ = True
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-- | Check if an URL links to an external HTTP(S) source
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--
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isExternal :: String -> Bool
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isExternal url = any (flip isPrefixOf url) ["http://", "https://"]
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