{-# LANGUAGE OverloadedStrings #-}
{-
Copyright (C) 2011-2016 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) 2011-2016 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 ( makeDataURI, makeSelfContained ) where
import Codec.Compression.GZip as Gzip
import Control.Applicative ((<|>))
import Control.Monad.Except (throwError)
import Control.Monad.Trans (lift)
import Data.ByteString (ByteString)
import Data.ByteString.Base64
import qualified Data.ByteString.Char8 as B
import qualified Data.ByteString.Lazy as L
import Data.Char (isAlphaNum, isAscii, toLower)
import Data.List (isPrefixOf)
import Network.URI (URI (..), escapeURIString, isURI, parseURI)
import System.FilePath (takeDirectory, takeExtension, (</>))
import Text.HTML.TagSoup
import Text.Pandoc.Class (PandocMonad (..), fetchItem, report)
import Text.Pandoc.Error
import Text.Pandoc.Logging
import Text.Pandoc.MIME (MimeType)
import Text.Pandoc.Options (WriterOptions (..))
import Text.Pandoc.Shared (renderTags', trim)
import Text.Pandoc.UTF8 (toString)
import Text.Parsec (ParsecT, runParserT)
import qualified Text.Parsec as P
isOk :: Char -> Bool
isOk c = isAscii c && isAlphaNum c
makeDataURI :: (MimeType, ByteString) -> String
makeDataURI (mime, raw) =
if textual
then "data:" ++ mime' ++ "," ++ escapeURIString isOk (toString raw)
else "data:" ++ mime' ++ ";base64," ++ toString (encode raw)
where textual = "text/" `Data.List.isPrefixOf` mime
mime' = if textual && ';' `notElem` mime
then mime ++ ";charset=utf-8"
else mime -- mime type already has charset
convertTags :: PandocMonad m => Maybe String -> [Tag String] -> m [Tag String]
convertTags _ [] = return []
convertTags sourceURL (t@TagOpen{}:ts)
| fromAttrib "data-external" t == "1" = (t:) <$> convertTags sourceURL ts
convertTags sourceURL (t@(TagOpen tagname as):ts)
| tagname `elem`
["img", "embed", "video", "input", "audio", "source", "track"] = do
as' <- mapM processAttribute as
rest <- convertTags sourceURL ts
return $ TagOpen tagname as' : rest
where processAttribute (x,y) =
if x == "src" || x == "data-src" || x == "href" || x == "poster"
then do
enc <- getDataURI sourceURL (fromAttrib "type" t) y
return (x, enc)
else return (x,y)
convertTags sourceURL (t@(TagOpen "script" as):TagClose "script":ts) =
case fromAttrib "src" t of
[] -> (t:) <$> convertTags sourceURL ts
src -> do
let typeAttr = fromAttrib "type" t
res <- getData sourceURL typeAttr src
rest <- convertTags sourceURL ts
case res of
Left dataUri -> return $ TagOpen "script"
(("src",dataUri) : [(x,y) | (x,y) <- as, x /= "src"]) :
TagClose "script" : rest
Right (mime, bs)
| (mime == "text/javascript" ||
mime == "application/javascript" ||
mime == "application/x-javascript") &&
not ("</script" `B.isInfixOf` bs) ->
return $
TagOpen "script" [("type", typeAttr)|not (null typeAttr)]
: TagText (toString bs)
: TagClose "script"
: rest
| otherwise ->
return $ TagOpen "script"
(("src",makeDataURI (mime, bs)) :
[(x,y) | (x,y) <- as, x /= "src"]) :
TagClose "script" : rest
convertTags sourceURL (t@(TagOpen "link" as):ts) =
case fromAttrib "href" t of
[] -> (t:) <$> convertTags sourceURL ts
src -> do
res <- getData sourceURL (fromAttrib "type" t) src
case res of
Left dataUri -> do
rest <- convertTags sourceURL ts
return $ TagOpen "link"
(("href",dataUri) : [(x,y) | (x,y) <- as, x /= "href"]) :
rest
Right (mime, bs)
| mime == "text/css" && not ("</" `B.isInfixOf` bs) -> do
rest <- convertTags sourceURL $
dropWhile (==TagClose "link") ts
return $
TagOpen "style" [("type", "text/css")]
: TagText (toString bs)
: TagClose "style"
: rest
| otherwise -> do
rest <- convertTags sourceURL ts
return $ TagOpen "link"
(("href",makeDataURI (mime, bs)) :
[(x,y) | (x,y) <- as, x /= "href"]) : rest
convertTags sourceURL (t:ts) = (t:) <$> convertTags sourceURL ts
cssURLs :: PandocMonad m
=> Maybe String -> FilePath -> ByteString -> m ByteString
cssURLs sourceURL d orig = do
res <- runParserT (parseCSSUrls sourceURL d) () "css" orig
case res of
Left e -> do
report $ CouldNotParseCSS (show e)
return orig
Right bs -> return bs
parseCSSUrls :: PandocMonad m
=> Maybe String -> FilePath -> ParsecT ByteString () m ByteString
parseCSSUrls sourceURL d = B.concat <$> P.many
(pCSSWhite <|> pCSSComment <|> pCSSUrl sourceURL d <|> pCSSOther)
-- Note: some whitespace in CSS is significant, so we can't collapse it!
pCSSWhite :: PandocMonad m => ParsecT ByteString () m ByteString
pCSSWhite = B.singleton <$> P.space <* P.spaces
pCSSComment :: PandocMonad m => ParsecT ByteString () m ByteString
pCSSComment = P.try $ do
P.string "/*"
P.manyTill P.anyChar (P.try (P.string "*/"))
return B.empty
pCSSOther :: PandocMonad m => ParsecT ByteString () m ByteString
pCSSOther = do
(B.pack <$> P.many1 (P.noneOf "u/ \n\r\t")) <|>
(B.singleton <$> P.char 'u') <|>
(B.singleton <$> P.char '/')
pCSSUrl :: PandocMonad m
=> Maybe String -> FilePath -> ParsecT ByteString () m ByteString
pCSSUrl sourceURL d = P.try $ do
P.string "url("
P.spaces
quote <- P.option Nothing (Just <$> P.oneOf "\"'")
url <- P.manyTill P.anyChar (maybe (P.lookAhead (P.char ')')) P.char quote)
P.spaces
P.char ')'
let fallback = B.pack ("url(" ++ maybe "" (:[]) quote ++ trim url ++
maybe "" (:[]) quote ++ ")")
case trim url of
'#':_ -> return fallback
'd':'a':'t':'a':':':_ -> return fallback
u -> do let url' = if isURI u then u else d </> u
enc <- lift $ getDataURI sourceURL "" url'
return (B.pack $ "url(" ++ enc ++ ")")
getDataURI :: PandocMonad m => Maybe String -> MimeType -> String -> m String
getDataURI sourceURL mimetype src = do
res <- getData sourceURL mimetype src
case res of
Left uri -> return uri
Right x -> return $ makeDataURI x
getData :: PandocMonad m
=> Maybe String -> MimeType -> String
-> m (Either String (MimeType, ByteString))
getData _ _ src@('d':'a':'t':'a':':':_) = return $ Left src-- already data: uri
getData sourceURL mimetype src = do
let ext = map toLower $ takeExtension src
(raw, respMime) <- fetchItem sourceURL src
let raw' = if ext == ".gz"
then B.concat $ L.toChunks $ Gzip.decompress $ L.fromChunks
$ [raw]
else raw
mime <- case (mimetype, respMime) of
("",Nothing) -> throwError $ PandocSomeError
$ "Could not determine mime type for `" ++ src ++ "'"
(x, Nothing) -> return x
(_, Just x ) -> return x
let cssSourceURL = case parseURI src of
Just u
| uriScheme u `elem` ["http:","https:"] ->
Just $ show u{ uriPath = "",
uriQuery = "",
uriFragment = "" }
_ -> Nothing
result <- if mime == "text/css"
then cssURLs cssSourceURL (takeDirectory src) raw'
else return raw'
return $ Right (mime, result)
-- | Convert HTML into self-contained HTML, incorporating images,
-- scripts, and CSS using data: URIs.
makeSelfContained :: PandocMonad m => WriterOptions -> String -> m String
makeSelfContained opts inp = do
let tags = parseTags inp
out' <- convertTags (writerSourceURL opts) tags
return $ renderTags' out'