yesod/yesod-static/Yesod/EmbeddedStatic/Css/AbsoluteUrl.hs
2014-04-21 22:07:21 -07:00

81 lines
3.0 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
-- | Manipulate CSS urls.
--
-- * Make relative urls absolute (useful when combining assets)
module Yesod.EmbeddedStatic.Css.AbsoluteUrl (
-- * Absolute urls
absoluteUrls
, absoluteUrlsAt
, absoluteUrlsWith
, absCssUrlsFileProd
, absCssUrlsProd
) where
import Prelude hiding (FilePath)
import Yesod.EmbeddedStatic.Generators
import Yesod.EmbeddedStatic.Types
import qualified Data.ByteString.Lazy as BL
import qualified Data.Text as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.IO as T
import qualified Data.Text.Lazy.Encoding as TL
import Control.Monad ((>=>))
import Data.Maybe (fromMaybe)
import Filesystem.Path.CurrentOS ((</>), collapse, FilePath, fromText, toText, encodeString, decodeString)
import Yesod.EmbeddedStatic.Css.Util
-------------------------------------------------------------------------------
-- Generator
-------------------------------------------------------------------------------
-- | Anchors relative CSS image urls
absCssUrlsFileProd :: FilePath -- ^ Anchor relative urls to here
-> FilePath
-> IO BL.ByteString
absCssUrlsFileProd dir file = do
contents <- T.readFile (encodeString file)
return $ TL.encodeUtf8 $ absCssUrlsProd dir contents
absCssUrlsProd :: FilePath -- ^ Anchor relative urls to here
-> T.Text
-> TL.Text
absCssUrlsProd dir contents =
let css = either error id $ parseCssUrls contents
in renderCssWith toAbsoluteUrl css
where
toAbsoluteUrl (UrlReference rel) = T.concat
[ "url('/"
, (either id id $ toText $ collapse $ dir </> fromText rel)
, "')"
]
-- | Equivalent to passing the same string twice to 'absoluteUrlsAt'.
absoluteUrls :: FilePath -> Generator
absoluteUrls f = absoluteUrlsAt (encodeString f) f
-- | Equivalent to passing @return@ to 'absoluteUrlsWith'.
absoluteUrlsAt :: Location -> FilePath -> Generator
absoluteUrlsAt loc f = absoluteUrlsWith loc f Nothing
-- | Automatically make relative urls absolute
--
-- During development, leave CSS as is.
--
-- When CSS is organized into a directory structure, it will work properly for individual requests for each file.
-- During production, we want to combine and minify CSS as much as possible.
-- The combination process combines files from different directories, messing up relative urls.
-- This pre-processor makes relative urls absolute
absoluteUrlsWith ::
Location -- ^ The location the CSS file should appear in the static subsite
-> FilePath -- ^ Path to the CSS file.
-> Maybe (CssGeneration -> IO BL.ByteString) -- ^ Another filter function run after this one (for example @return . yuiCSS . cssContent@) or other CSS filter that runs after this filter.
-> Generator
absoluteUrlsWith loc file mpostFilter =
return [ cssProductionFilter (absCssUrlsFileProd (decodeString loc) >=> postFilter . mkCssGeneration loc file) loc file
]
where
postFilter = fromMaybe (return . cssContent) mpostFilter