1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
Module : Text.Pandoc.SelfContained
Copyright : Copyright (C) 2011-2019 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 Prelude
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 (escapeURIString)
import System.FilePath (takeDirectory, takeExtension, (</>))
import Text.HTML.TagSoup
import Text.Pandoc.Class (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)
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 => [Tag String] -> m [Tag String]
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" `isPrefixOf` mime ||
"application/javascript" `isPrefixOf` mime ||
"application/x-javascript" `isPrefixOf` mime) &&
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 (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" `isPrefixOf` mime
&& null (fromAttrib "media" t)
&& not ("</" `B.isInfixOf` bs) -> do
rest <- convertTags $
dropWhile (==TagClose "link") ts
return $
TagOpen "style" [("type", mime)]
: TagText (toString 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 (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 (B.pack $ "url(" ++ enc ++ ")")
pQuoted :: PandocMonad m
=> ParsecT ByteString () m (String, ByteString)
pQuoted = P.try $ do
quote <- P.oneOf "\"'"
url <- P.manyTill P.anyChar (P.char quote)
let fallback = B.pack ([quote] ++ trim url ++ [quote])
return (url, fallback)
pUrl :: PandocMonad m
=> ParsecT ByteString () m (String, ByteString)
pUrl = 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 ++ ")")
return (url, fallback)
handleCSSUrl :: PandocMonad m
=> FilePath -> (String, ByteString)
-> ParsecT ByteString () m
(Either ByteString (MimeType, ByteString))
handleCSSUrl d (url, fallback) =
case escapeURIString (/='|') (trim url) of
'#':_ -> return $ Left fallback
'd':'a':'t':'a':':':_ -> return $ Left fallback
u -> do let url' = if isURI u then u else d </> u
res <- lift $ getData "" url'
case res of
Left uri -> return $ Left (B.pack $ "url(" ++ uri ++ ")")
Right (mt, raw) -> do
-- note that the downloaded CSS may
-- itself contain url(...).
b <- if "text/css" `isPrefixOf` mt
then cssURLs d raw
else return raw
return $ Right (mt, b)
getDataURI :: PandocMonad m => MimeType -> String -> m String
getDataURI mimetype src = do
res <- getData mimetype src
case res of
Left uri -> return uri
Right x -> return $ makeDataURI x
getData :: PandocMonad m
=> MimeType -> String
-> m (Either String (MimeType, ByteString))
getData _ src@('d':'a':'t':'a':':':_) = return $ Left src-- already data: uri
getData mimetype src = do
let ext = map toLower $ takeExtension 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" `isPrefixOf` mime
then do
oldInputs <- getInputFiles
setInputFiles [src]
res <- cssURLs (takeDirectory 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 => String -> m String
makeSelfContained inp = do
let tags = parseTags inp
out' <- convertTags tags
return $ renderTags' out'
|
