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|
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TupleSections #-}
{- |
Module : Text.Pandoc.SelfContained
Copyright : Copyright (C) 2011-2020 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 qualified Data.Text as T
import Data.Char (isAlphaNum, isAscii)
import Network.URI (escapeURIString)
import System.FilePath (takeDirectory, takeExtension, (</>))
import Text.HTML.TagSoup
import Text.Pandoc.Class.PandocMonad (PandocMonad (..), fetchItem,
getInputFiles, report, setInputFiles)
import Text.Pandoc.Error
import Text.Pandoc.Logging
import Text.Pandoc.MIME (MimeType)
import Text.Pandoc.Shared (isURI, renderTags', trim)
import Text.Pandoc.UTF8 (toString, toText, fromText)
import Text.Parsec (ParsecT, runParserT)
import qualified Text.Parsec as P
isOk :: Char -> Bool
isOk c = isAscii c && isAlphaNum c
makeDataURI :: (MimeType, ByteString) -> T.Text
makeDataURI (mime, raw) =
if textual
then "data:" <> mime' <> "," <> T.pack (escapeURIString isOk (toString raw))
else "data:" <> mime' <> ";base64," <> toText (encode raw)
where textual = "text/" `T.isPrefixOf` mime
mime' = if textual && T.any (== ';') mime
then mime <> ";charset=utf-8"
else mime -- mime type already has charset
convertTags :: PandocMonad m => [Tag T.Text] -> m [Tag T.Text]
convertTags [] = return []
convertTags (t@TagOpen{}:ts)
| fromAttrib "data-external" t == "1" = (t:) <$> convertTags ts
convertTags (t@(TagOpen tagname as):ts)
| tagname `elem`
["img", "embed", "video", "input", "audio", "source", "track",
"section"] = do
as' <- mapM processAttribute as
rest <- convertTags ts
return $ TagOpen tagname as' : rest
where processAttribute (x,y) =
if x `elem` ["src", "data-src", "href", "poster", "data-background-image"]
then do
enc <- getDataURI (fromAttrib "type" t) y
return (x, enc)
else return (x,y)
convertTags (t@(TagOpen "script" as):TagClose "script":ts) =
case fromAttrib "src" t of
"" -> (t:) <$> convertTags ts
src -> do
let typeAttr = fromAttrib "type" t
res <- getData typeAttr src
rest <- convertTags ts
case res of
Left dataUri -> return $ TagOpen "script"
(("src",dataUri) : [(x,y) | (x,y) <- as, x /= "src"]) :
TagClose "script" : rest
Right (mime, bs)
| ("text/javascript" `T.isPrefixOf` mime ||
"application/javascript" `T.isPrefixOf` mime ||
"application/x-javascript" `T.isPrefixOf` mime) &&
not ("</script" `B.isInfixOf` bs) ->
return $
TagOpen "script" [("type", typeAttr)|not (T.null typeAttr)]
: TagText (toText bs)
: TagClose "script"
: rest
| otherwise ->
return $ TagOpen "script"
(("src",makeDataURI (mime, bs)) :
[(x,y) | (x,y) <- as, x /= "src"]) :
TagClose "script" : rest
convertTags (t@(TagOpen "link" as):ts) =
case fromAttrib "href" t of
"" -> (t:) <$> convertTags ts
src -> do
res <- getData (fromAttrib "type" t) src
case res of
Left dataUri -> do
rest <- convertTags ts
return $ TagOpen "link"
(("href",dataUri) : [(x,y) | (x,y) <- as, x /= "href"]) :
rest
Right (mime, bs)
| "text/css" `T.isPrefixOf` mime
&& T.null (fromAttrib "media" t)
&& not ("</" `B.isInfixOf` bs) -> do
rest <- convertTags $
dropWhile (==TagClose "link") ts
return $
TagOpen "style" [("type", "text/css")] -- see #5725
: TagText (toText bs)
: TagClose "style"
: rest
| otherwise -> do
rest <- convertTags ts
return $ TagOpen "link"
(("href",makeDataURI (mime, bs)) :
[(x,y) | (x,y) <- as, x /= "href"]) : rest
convertTags (t:ts) = (t:) <$> convertTags ts
cssURLs :: PandocMonad m
=> FilePath -> ByteString -> m ByteString
cssURLs d orig = do
res <- runParserT (parseCSSUrls d) () "css" orig
case res of
Left e -> do
report $ CouldNotParseCSS $ T.pack $ show e
return orig
Right bs -> return bs
parseCSSUrls :: PandocMonad m
=> FilePath -> ParsecT ByteString () m ByteString
parseCSSUrls d = B.concat <$> P.many
(pCSSWhite <|> pCSSComment <|> pCSSImport d <|> pCSSUrl d <|> pCSSOther)
pCSSImport :: PandocMonad m
=> FilePath -> ParsecT ByteString () m ByteString
pCSSImport d = P.try $ do
P.string "@import"
P.spaces
res <- (pQuoted <|> pUrl) >>= handleCSSUrl d
P.spaces
P.char ';'
P.spaces
case res of
Left b -> return $ B.pack "@import " <> b
Right (_, b) -> return b
-- 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 =
(B.pack <$> P.many1 (P.noneOf "u/ \n\r\t")) <|>
(B.singleton <$> P.char 'u') <|>
(B.singleton <$> P.char '/')
pCSSUrl :: PandocMonad m
=> FilePath -> ParsecT ByteString () m ByteString
pCSSUrl d = P.try $ do
res <- pUrl >>= handleCSSUrl d
case res of
Left b -> return b
Right (mt,b) -> do
let enc = makeDataURI (mt, b)
return $ fromText $ "url(" <> enc <> ")"
pQuoted :: PandocMonad m
=> ParsecT ByteString () m (T.Text, ByteString)
pQuoted = P.try $ do
quote <- P.oneOf "\"'"
url <- T.pack <$> P.manyTill P.anyChar (P.char quote)
let fallback = fromText $ T.singleton quote <> trim url <> T.singleton quote
return (url, fallback)
pUrl :: PandocMonad m
=> ParsecT ByteString () m (T.Text, ByteString)
pUrl = P.try $ do
P.string "url("
P.spaces
quote <- P.option Nothing (Just <$> P.oneOf "\"'")
url <- T.pack <$> P.manyTill P.anyChar (maybe (P.lookAhead (P.char ')')) P.char quote)
P.spaces
P.char ')'
let fallback = fromText ("url(" <> maybe "" T.singleton quote <> trim url <>
maybe "" T.singleton quote <> ")")
return (url, fallback)
handleCSSUrl :: PandocMonad m
=> FilePath -> (T.Text, ByteString)
-> ParsecT ByteString () m
(Either ByteString (MimeType, ByteString))
handleCSSUrl d (url, fallback) =
case escapeURIString (/='|') (T.unpack $ trim url) of
'#':_ -> return $ Left fallback
'd':'a':'t':'a':':':_ -> return $ Left fallback
u -> do let url' = if isURI (T.pack u) then T.pack u else T.pack (d </> u)
res <- lift $ getData "" url'
case res of
Left uri -> return $ Left (fromText $ "url(" <> uri <> ")")
Right (mt', raw) -> do
-- note that the downloaded CSS may
-- itself contain url(...).
(mt, b) <- if "text/css" `T.isPrefixOf` mt'
-- see #5725: in HTML5, content type
-- isn't allowed on style type attribute
then ("text/css",) <$> cssURLs d raw
else return (mt', raw)
return $ Right (mt, b)
getDataURI :: PandocMonad m => MimeType -> T.Text -> m T.Text
getDataURI mimetype src = do
res <- getData mimetype src
case res of
Left uri -> return uri
Right x -> return $ makeDataURI x
getData :: PandocMonad m
=> MimeType -> T.Text
-> m (Either T.Text (MimeType, ByteString))
getData mimetype src
| "data:" `T.isPrefixOf` src = return $ Left src -- already data: uri
| otherwise = do
let ext = T.toLower $ T.pack $ takeExtension $ T.unpack src
(raw, respMime) <- fetchItem src
let raw' = if ext `elem` [".gz", ".svgz"]
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
result <- if "text/css" `T.isPrefixOf` mime
then do
oldInputs <- getInputFiles
setInputFiles [T.unpack src]
res <- cssURLs (takeDirectory $ T.unpack src) raw'
setInputFiles oldInputs
return res
else return raw'
return $ Right (mime, result)
-- | Convert HTML into self-contained HTML, incorporating images,
-- scripts, and CSS using data: URIs.
makeSelfContained :: PandocMonad m => T.Text -> m T.Text
makeSelfContained inp = do
let tags = parseTags inp
out' <- convertTags tags
return $ renderTags' out'
|
