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{-# LANGUAGE OverloadedStrings #-}
{-
Copyright (C) 2011-2014 John MacFarlane <jgm@berkeley.edu>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : Text.Pandoc.SelfContained
Copyright : Copyright (C) 2011-2014 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Functions for converting an HTML file into one that can be viewed
offline, by incorporating linked images, CSS, and scripts into
the HTML using data URIs.
-}
module Text.Pandoc.SelfContained ( makeSelfContained ) where
import Text.HTML.TagSoup
import Network.URI (isURI, escapeURIString)
import Data.ByteString.Base64
import qualified Data.ByteString.Char8 as B
import Data.ByteString (ByteString)
import System.FilePath (takeExtension, dropExtension, takeDirectory, (</>))
import Data.Char (toLower, isAscii, isAlphaNum)
import Codec.Compression.GZip as Gzip
import qualified Data.ByteString.Lazy as L
import Text.Pandoc.Shared (renderTags', openURL, readDataFile, err)
import Text.Pandoc.UTF8 (toString, fromString)
import Text.Pandoc.MIME (getMimeType)
import System.Directory (doesFileExist)
isOk :: Char -> Bool
isOk c = isAscii c && isAlphaNum c
convertTag :: Maybe FilePath -> Tag String -> IO (Tag String)
convertTag userdata t@(TagOpen tagname as)
| tagname `elem` ["img", "embed", "video", "input", "audio", "source"] = do
as' <- mapM processAttribute as
return $ TagOpen tagname as'
where processAttribute (x,y) =
if x == "src" || x == "href" || x == "poster"
then do
(raw, mime) <- getRaw userdata (fromAttrib "type" t) y
let enc = "data:" ++ mime ++ ";base64," ++ toString (encode raw)
return (x, enc)
else return (x,y)
convertTag userdata t@(TagOpen "script" as) =
case fromAttrib "src" t of
[] -> return t
src -> do
(raw, mime) <- getRaw userdata (fromAttrib "type" t) src
let enc = "data:" ++ mime ++ "," ++ escapeURIString isOk (toString raw)
return $ TagOpen "script" (("src",enc) : [(x,y) | (x,y) <- as, x /= "src"])
convertTag userdata t@(TagOpen "link" as) =
case fromAttrib "href" t of
[] -> return t
src -> do
(raw, mime) <- getRaw userdata (fromAttrib "type" t) src
let enc = "data:" ++ mime ++ "," ++ escapeURIString isOk (toString raw)
return $ TagOpen "link" (("href",enc) : [(x,y) | (x,y) <- as, x /= "href"])
convertTag _ t = return t
-- NOTE: This is really crude, it doesn't respect CSS comments.
cssURLs :: Maybe FilePath -> FilePath -> ByteString -> IO ByteString
cssURLs userdata d orig =
case B.breakSubstring "url(" orig of
(x,y) | B.null y -> return orig
| otherwise -> do
let (u,v) = B.breakSubstring ")" $ B.drop 4 y
let url = toString
$ case B.take 1 u of
"\"" -> B.takeWhile (/='"') $ B.drop 1 u
"'" -> B.takeWhile (/='\'') $ B.drop 1 u
_ -> u
let url' = if isURI url
then url
else d </> url
(raw, mime) <- getRaw userdata "" url'
rest <- cssURLs userdata d v
let enc = "data:" `B.append` fromString mime `B.append`
";base64," `B.append` (encode raw)
return $ x `B.append` "url(" `B.append` enc `B.append` rest
getItem :: Maybe FilePath -> String -> IO (ByteString, Maybe String)
getItem userdata f =
if isURI f
then openURL f >>= either handleErr return
else do
-- strip off trailing query or fragment part, if relative URL.
-- this is needed for things like cmunrm.eot?#iefix,
-- which is used to get old versions of IE to work with web fonts.
let f' = takeWhile (\c -> c /= '?' && c /= '#') f
let mime = case takeExtension f' of
".gz" -> getMimeType $ dropExtension f'
x -> getMimeType x
exists <- doesFileExist f'
cont <- if exists then B.readFile f' else readDataFile userdata f'
return (cont, mime)
where handleErr e = err 61 $ "Failed to retrieve " ++ f ++ "\n" ++ show e
getRaw :: Maybe FilePath -> String -> String -> IO (ByteString, String)
getRaw userdata mimetype src = do
let ext = map toLower $ takeExtension src
(raw, respMime) <- getItem userdata src
let raw' = if ext == ".gz"
then B.concat $ L.toChunks $ Gzip.decompress $ L.fromChunks
$ [raw]
else raw
let mime = case (mimetype, respMime) of
("",Nothing) -> error
$ "Could not determine mime type for `" ++ src ++ "'"
(x, Nothing) -> x
(_, Just x ) -> x
result <- if mime == "text/css"
then cssURLs userdata (takeDirectory src) raw'
else return raw'
return (result, mime)
-- | Convert HTML into self-contained HTML, incorporating images,
-- scripts, and CSS using data: URIs. Items specified using absolute
-- URLs will be downloaded; those specified using relative URLs will
-- be sought first relative to the working directory, then relative
-- to the user data directory (if the first parameter is 'Just'
-- a directory), and finally relative to pandoc's default data
-- directory.
makeSelfContained :: Maybe FilePath -> String -> IO String
makeSelfContained userdata inp = do
let tags = parseTags inp
out' <- mapM (convertTag userdata) tags
return $ renderTags' out'
|
