pandoc/src/Text/Pandoc/Writers/EPUB.hs

375 lines
17 KiB
Haskell

{-
Copyright (C) 2010 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.Writers.EPUB
Copyright : Copyright (C) 2010 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Conversion of 'Pandoc' documents to EPUB.
-}
module Text.Pandoc.Writers.EPUB ( writeEPUB ) where
import Data.IORef
import Data.Maybe ( fromMaybe, isNothing )
import Data.List ( findIndices, isPrefixOf )
import System.Environment ( getEnv )
import System.FilePath ( (</>), (<.>), takeBaseName, takeExtension, takeFileName )
import qualified Data.ByteString.Lazy as B
import Data.ByteString.Lazy.UTF8 ( fromString )
import Codec.Archive.Zip
import Data.Time.Clock.POSIX
import Text.Pandoc.Shared hiding ( Element )
import Text.Pandoc.Definition
import Text.Pandoc.Generic
import Control.Monad.State
import Text.XML.Light hiding (ppTopElement)
import Text.Pandoc.UUID
import Text.Pandoc.Writers.HTML
import Text.Pandoc.Writers.Markdown ( writePlain )
import Data.Char ( toLower )
import Network.URI ( unEscapeString )
import Text.Pandoc.MIME (getMimeType)
import Prelude hiding (catch)
import Control.Exception (catch, SomeException)
-- | Produce an EPUB file from a Pandoc document.
writeEPUB :: Maybe String -- ^ EPUB stylesheet specified at command line
-> [FilePath] -- ^ Paths to fonts to embed
-> WriterOptions -- ^ Writer options
-> Pandoc -- ^ Document to convert
-> IO B.ByteString
writeEPUB mbStylesheet fonts opts doc@(Pandoc meta _) = do
epochtime <- floor `fmap` getPOSIXTime
let mkEntry path content = toEntry path epochtime content
let opts' = opts{ writerEmailObfuscation = NoObfuscation
, writerStandalone = True
, writerWrapText = False }
let sourceDir = writerSourceDirectory opts'
let vars = writerVariables opts'
let mbCoverImage = lookup "epub-cover-image" vars
titlePageTemplate <- readDataFile (writerUserDataDir opts)
$ "templates" </> "epub-titlepage" <.> "html"
coverImageTemplate <- readDataFile (writerUserDataDir opts)
$ "templates" </> "epub-coverimage" <.> "html"
pageTemplate <- readDataFile (writerUserDataDir opts)
$ "templates" </> "epub-page" <.> "html"
-- cover page
(cpgEntry, cpicEntry) <-
case mbCoverImage of
Nothing -> return ([],[])
Just img -> do
let coverImage = "cover-image" ++ takeExtension img
let cpContent = fromString $ writeHtmlString
opts'{writerTemplate = coverImageTemplate,
writerVariables = ("coverimage",coverImage):vars}
(Pandoc meta [])
imgContent <- B.readFile img
return ( [mkEntry "cover.xhtml" cpContent]
, [mkEntry coverImage imgContent] )
-- title page
let tpContent = fromString $ writeHtmlString
opts'{writerTemplate = titlePageTemplate}
(Pandoc meta [])
let tpEntry = mkEntry "title_page.xhtml" tpContent
-- handle pictures
picsRef <- newIORef []
Pandoc _ blocks <- bottomUpM
(transformInlines (writerHTMLMathMethod opts) sourceDir picsRef) doc
pics <- readIORef picsRef
let readPicEntry (oldsrc, newsrc) = readEntry [] oldsrc >>= \e ->
return e{ eRelativePath = newsrc }
picEntries <- mapM readPicEntry pics
-- handle fonts
let mkFontEntry f = mkEntry (takeFileName f) `fmap` B.readFile f
fontEntries <- mapM mkFontEntry fonts
-- body pages
let isH1 (Header 1 _) = True
isH1 _ = False
-- internal reference IDs change when we chunk the file,
-- so the next two lines fix that:
let reftable = correlateRefs blocks
let blocks' = replaceRefs reftable blocks
let h1Indices = dropWhile (== 0) $ findIndices isH1 blocks'
let chunks = splitByIndices h1Indices blocks'
let titleize (Header 1 xs : ys) = Pandoc meta{docTitle = xs} ys
titleize xs = Pandoc meta xs
let chapters = map titleize chunks
let chapToHtml = writeHtmlString opts'{ writerTemplate = pageTemplate }
let chapterToEntry :: Int -> Pandoc -> Entry
chapterToEntry num chap = mkEntry ("ch" ++ show num ++ ".xhtml") $
fromString $ chapToHtml chap
let chapterEntries = zipWith chapterToEntry [1..] chapters
-- contents.opf
localeLang <- catch (liftM (map (\c -> if c == '_' then '-' else c) .
takeWhile (/='.')) $ getEnv "LANG")
(\e -> let _ = (e :: SomeException) in return "en-US")
let lang = case lookup "lang" (writerVariables opts') of
Just x -> x
Nothing -> localeLang
uuid <- getRandomUUID
let chapterNode ent = unode "item" !
[("id", takeBaseName $ eRelativePath ent),
("href", eRelativePath ent),
("media-type", "application/xhtml+xml")] $ ()
let chapterRefNode ent = unode "itemref" !
[("idref", takeBaseName $ eRelativePath ent)] $ ()
let pictureNode ent = unode "item" !
[("id", takeBaseName $ eRelativePath ent),
("href", eRelativePath ent),
("media-type", fromMaybe "application/octet-stream"
$ imageTypeOf $ eRelativePath ent)] $ ()
let fontNode ent = unode "item" !
[("id", takeBaseName $ eRelativePath ent),
("href", eRelativePath ent),
("media-type", maybe "" id $ getMimeType $ eRelativePath ent)] $ ()
let plainify t = removeTrailingSpace $
writePlain opts'{ writerStandalone = False } $
Pandoc meta [Plain t]
let plainTitle = plainify $ docTitle meta
let plainAuthors = map plainify $ docAuthors meta
let plainDate = maybe "" id $ normalizeDate $ stringify $ docDate meta
let contentsData = fromString $ ppTopElement $
unode "package" ! [("version","2.0")
,("xmlns","http://www.idpf.org/2007/opf")
,("unique-identifier","BookId")] $
[ metadataElement (writerEPUBMetadata opts')
uuid lang plainTitle plainAuthors plainDate mbCoverImage
, unode "manifest" $
[ unode "item" ! [("id","ncx"), ("href","toc.ncx")
,("media-type","application/x-dtbncx+xml")] $ ()
, unode "item" ! [("id","style"), ("href","stylesheet.css")
,("media-type","text/css")] $ ()
] ++
map chapterNode (cpgEntry ++ (tpEntry : chapterEntries)) ++
map pictureNode (cpicEntry ++ picEntries) ++
map fontNode fontEntries
, unode "spine" ! [("toc","ncx")] $
case mbCoverImage of
Nothing -> []
Just _ -> [ unode "itemref" !
[("idref", "cover"),("linear","no")] $ () ]
++ map chapterRefNode (tpEntry : chapterEntries)
]
let contentsEntry = mkEntry "content.opf" contentsData
-- toc.ncx
let navPointNode ent n tit = unode "navPoint" !
[("id", "navPoint-" ++ show n)
,("playOrder", show n)] $
[ unode "navLabel" $ unode "text" tit
, unode "content" ! [("src",
eRelativePath ent)] $ ()
]
let tocData = fromString $ ppTopElement $
unode "ncx" ! [("version","2005-1")
,("xmlns","http://www.daisy.org/z3986/2005/ncx/")] $
[ unode "head" $
[ unode "meta" ! [("name","dtb:uid")
,("content", show uuid)] $ ()
, unode "meta" ! [("name","dtb:depth")
,("content", "1")] $ ()
, unode "meta" ! [("name","dtb:totalPageCount")
,("content", "0")] $ ()
, unode "meta" ! [("name","dtb:maxPageNumber")
,("content", "0")] $ ()
] ++ case mbCoverImage of
Nothing -> []
Just _ -> [unode "meta" ! [("name","cover"),
("content","cover-image")] $ ()]
, unode "docTitle" $ unode "text" $ plainTitle
, unode "navMap" $ zipWith3 navPointNode (tpEntry : chapterEntries)
[1..(length chapterEntries + 1)]
("Title Page" : map (\(Pandoc m _) ->
plainify $ docTitle m) chapters)
]
let tocEntry = mkEntry "toc.ncx" tocData
-- mimetype
let mimetypeEntry = mkEntry "mimetype" $ fromString "application/epub+zip"
-- container.xml
let containerData = fromString $ ppTopElement $
unode "container" ! [("version","1.0")
,("xmlns","urn:oasis:names:tc:opendocument:xmlns:container")] $
unode "rootfiles" $
unode "rootfile" ! [("full-path","content.opf")
,("media-type","application/oebps-package+xml")] $ ()
let containerEntry = mkEntry "META-INF/container.xml" containerData
-- com.apple.ibooks.display-options.xml
let apple = fromString $ ppTopElement $
unode "display_options" $
unode "platform" ! [("name","*")] $
unode "option" ! [("name","specified-fonts")] $ "true"
let appleEntry = mkEntry "META-INF/com.apple.ibooks.display-options.xml" apple
-- stylesheet
stylesheet <- case mbStylesheet of
Just s -> return s
Nothing -> readDataFile (writerUserDataDir opts) "epub.css"
let stylesheetEntry = mkEntry "stylesheet.css" $ fromString stylesheet
-- construct archive
let archive = foldr addEntryToArchive emptyArchive
(mimetypeEntry : containerEntry : appleEntry : stylesheetEntry : tpEntry :
contentsEntry : tocEntry :
(picEntries ++ cpicEntry ++ cpgEntry ++ chapterEntries ++ fontEntries) )
return $ fromArchive archive
metadataElement :: String -> UUID -> String -> String -> [String] -> String -> Maybe a -> Element
metadataElement metadataXML uuid lang title authors date mbCoverImage =
let userNodes = parseXML metadataXML
elt = unode "metadata" ! [("xmlns:dc","http://purl.org/dc/elements/1.1/")
,("xmlns:opf","http://www.idpf.org/2007/opf")] $
filter isDublinCoreElement $ onlyElems userNodes
dublinElements = ["contributor","coverage","creator","date",
"description","format","identifier","language","publisher",
"relation","rights","source","subject","title","type"]
isDublinCoreElement e = qPrefix (elName e) == Just "dc" &&
qName (elName e) `elem` dublinElements
contains e n = not (null (findElements (QName n Nothing (Just "dc")) e))
newNodes = [ unode "dc:title" title | not (elt `contains` "title") ] ++
[ unode "dc:language" lang | not (elt `contains` "language") ] ++
[ unode "dc:identifier" ! [("id","BookId")] $ show uuid |
not (elt `contains` "identifier") ] ++
[ unode "dc:creator" ! [("opf:role","aut")] $ a | a <- authors ] ++
[ unode "dc:date" date | not (elt `contains` "date") ] ++
[ unode "meta" ! [("name","cover"), ("content","cover-image")] $ () |
not (isNothing mbCoverImage) ]
in elt{ elContent = elContent elt ++ map Elem newNodes }
transformInlines :: HTMLMathMethod
-> FilePath
-> IORef [(FilePath, FilePath)] -- ^ (oldpath, newpath) images
-> [Inline]
-> IO [Inline]
transformInlines _ _ _ (Image lab (src,_) : xs) | isNothing (imageTypeOf src) =
return $ Emph lab : xs
transformInlines _ sourceDir picsRef (Image lab (src,tit) : xs) = do
let src' = unEscapeString src
pics <- readIORef picsRef
let oldsrc = sourceDir </> src'
let ext = takeExtension src'
newsrc <- case lookup oldsrc pics of
Just n -> return n
Nothing -> do
let new = "images/img" ++ show (length pics) ++ ext
modifyIORef picsRef ( (oldsrc, new): )
return new
return $ Image lab (newsrc, tit) : xs
transformInlines (MathML _) _ _ (x@(Math _ _) : xs) = do
let writeHtmlInline opts z = removeTrailingSpace $
writeHtmlString opts $ Pandoc (Meta [] [] []) [Plain [z]]
mathml = writeHtmlInline defaultWriterOptions{
writerHTMLMathMethod = MathML Nothing } x
fallback = writeHtmlInline defaultWriterOptions{
writerHTMLMathMethod = PlainMath } x
inOps = "<ops:switch xmlns:ops=\"http://www.idpf.org/2007/ops\">" ++
"<ops:case required-namespace=\"http://www.w3.org/1998/Math/MathML\">" ++
mathml ++ "</ops:case><ops:default>" ++ fallback ++ "</ops:default>" ++
"</ops:switch>"
result = if "<math" `isPrefixOf` mathml then inOps else mathml
return $ RawInline "html" result : xs
transformInlines _ _ _ xs = return xs
(!) :: Node t => (t -> Element) -> [(String, String)] -> t -> Element
(!) f attrs n = add_attrs (map (\(k,v) -> Attr (unqual k) v) attrs) (f n)
-- | Version of 'ppTopElement' that specifies UTF-8 encoding.
ppTopElement :: Element -> String
ppTopElement = ("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" ++) . unEntity . ppElement
-- unEntity removes numeric entities introduced by ppElement
-- (kindlegen seems to choke on these).
where unEntity [] = ""
unEntity ('&':'#':xs) =
let (ds,ys) = break (==';') xs
rest = drop 1 ys
in case reads ('\'':'\\':ds ++ "'") of
((x,_):_) -> x : unEntity rest
_ -> '&':'#':unEntity xs
unEntity (x:xs) = x : unEntity xs
imageTypeOf :: FilePath -> Maybe String
imageTypeOf x = case drop 1 (map toLower (takeExtension x)) of
"jpg" -> Just "image/jpeg"
"jpeg" -> Just "image/jpeg"
"jfif" -> Just "image/jpeg"
"png" -> Just "image/png"
"gif" -> Just "image/gif"
"svg" -> Just "image/svg+xml"
_ -> Nothing
data IdentState = IdentState{
chapterNumber :: Int,
runningIdents :: [String],
chapterIdents :: [String],
identTable :: [(String,String)]
} deriving (Read, Show)
-- Go through a block list and construct a table
-- correlating the automatically constructed references
-- that would be used in a normal pandoc document with
-- new URLs to be used in the EPUB. For example, what
-- was "header-1" might turn into "ch6.xhtml#header".
correlateRefs :: [Block] -> [(String,String)]
correlateRefs bs = identTable $ execState (mapM_ go bs)
IdentState{ chapterNumber = 0
, runningIdents = []
, chapterIdents = []
, identTable = [] }
where go :: Block -> State IdentState ()
go (Header n ils) = do
when (n == 1) $
modify $ \s -> s{ chapterNumber = chapterNumber s + 1
, chapterIdents = [] }
st <- get
let runningid = uniqueIdent ils (runningIdents st)
let chapid = if n == 1
then Nothing
else Just $ uniqueIdent ils (chapterIdents st)
modify $ \s -> s{ runningIdents = runningid : runningIdents st
, chapterIdents = maybe (chapterIdents st)
(: chapterIdents st) chapid
, identTable = (runningid, "ch" ++ show (chapterNumber st) ++
".xhtml" ++ maybe "" ('#':) chapid) : identTable st
}
go _ = return ()
-- Replace internal link references using the table produced
-- by correlateRefs.
replaceRefs :: [(String,String)] -> [Block] -> [Block]
replaceRefs refTable = bottomUp replaceOneRef
where replaceOneRef x@(Link lab ('#':xs,tit)) =
case lookup xs refTable of
Just url -> Link lab (url,tit)
Nothing -> x
replaceOneRef x = x