Class: Bindery::Formats::Epub

Inherits:
Object
  • Object
show all
Defined in:
lib/bindery/formats/epub.rb

Overview

Builds an EPUB book file from the book description.

The EPUB Wikipedia entry provides a nice, concise overview of the EPUB format.

For more precise details:

Defined Under Namespace

Modules: BookMethods, ChapterMethods Classes: ManifestEntry

Constant Summary collapse

MimeTypes = 
{
  '.jpg' => 'image/jpeg',
  '.png' => 'image/png',
  '.gif' => 'image/gif',
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(book) ⇒ Epub

Returns a new instance of Epub.



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# File 'lib/bindery/formats/epub.rb', line 35

def initialize(book)
  self.book = book
  book.extend BookMethods
  book.chapters.each{|chapter| chapter.extend ChapterMethods}
  self.manifest_entries = []
end

Instance Attribute Details

#book ⇒ Object

Returns the value of attribute book.



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# File 'lib/bindery/formats/epub.rb', line 33

def book
  @book
end

#manifest_entries ⇒ Object

Returns the value of attribute manifest_entries.



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# File 'lib/bindery/formats/epub.rb', line 33

def manifest_entries
  @manifest_entries
end

Instance Method Details

#add_manifest_entry(file_name) ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 197

def add_manifest_entry(file_name)
  xml_id, ext = File.base_parts(file_name.gsub('/', '-'))
  manifest_entries << ManifestEntry.new(file_name, xml_id, MimeTypes[ext])
end

#container ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 69

def container
  %q{|<?xml version="1.0" encoding="UTF-8" ?>
     |<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
     |  <rootfiles>
     |    <rootfile full-path="book.opf" media-type="application/oebps-package+xml"/>
     |  </rootfiles>
     |</container>
     |}.strip_margin
end

#cover ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 202

def cover
  xm = Builder::XmlMarkup.new(:indent => 2)
  xm.instruct!
  xm.declare!(:DOCTYPE, :html, :PUBLIC, '-//W3C//DTD XHTML 1.1//END', 'http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd')
  xm.html('xmlns'=>'http://www.w3.org/1999/xhtml') { # ??? xml:lang attribute?
    xm.head {
      xm.title "#{book.title}: Cover"
      xm.meta('http-equiv'=>'Content-Type', 'content'=>'application/xhtml+xml; charset=utf-8')
    }
    xm.body {
      xm.div('style'=>'text-align: center; page-break-after: always;') {
        if book.cover
          xm.img('src'=>"images/#{book.cover}", 'alt'=>book.title, 'style'=>'height: 100%; max-width: 100%;')
        else
          xm.h1 book.title
          xm.h2 book.subtitle if book.subtitle
          xm.h3 "by #{book.author}" if book.author
        end
      }
    }
  }
end

#generate ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 42

def generate
  File.delete(book.epub_output_file) if File.exist?(book.epub_output_file)
  Zip::ZipFile.open(book.epub_output_file, Zip::ZipFile::CREATE) do |zipfile|
    # FIXME: The mimetype file is supposed to be the first one in the Zip directory, but that doesn't seem to be happening.
    zipfile.write_uncompressed_file 'mimetype', mimetype
    zipfile.mkdir 'META-INF'
    zipfile.write_file 'META-INF/container.xml', container
    
    # also frontmatter, backmatter
    book.chapters.each do |chapter|
      write_chapter(chapter, zipfile)
    end
    
    zipfile.mkdir 'css'
    zipfile.write_file 'css/book.css', stylesheet

    zipfile.write_file 'book.opf', opf
    zipfile.write_file 'book.ncx', ncx
  end
end

#ident_options(opts) ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 259

def ident_options(opts)
  if book.isbn
    return opts.merge('id'=>'BookId') if opts['opf:scheme'] == 'ISBN'
  else
    return opts.merge('id'=>'BookId') if opts['opf:scheme'] == 'URL'
  end
  opts
end

#include_images(doc, zipfile) ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 180

def include_images(doc, zipfile)
  # TODO: where else can images appear? Style sheets?
  zipfile.mkdir('images') unless zip_dir_exists?(zipfile, 'images')
  doc.css('img').each do |img|
    url = img['src']
    img_fn = make_image_file_name(zipfile, url)
    # TODO: These images should be cached somewhere for multi-format runs
    open(url, 'r') do |is|
      zipfile.get_output_stream(img_fn) do |os|
        os.write is.read
      end
    end
    add_manifest_entry(img_fn)
    img['src'] = img_fn
  end
end

#make_image_file_name(zipfile, url) ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 277

def make_image_file_name(zipfile, url)
  stem, ext = File.base_parts(url)
  filename = "images/#{stem}#{ext}"
  n = 0
  while zip_file_exists?(zipfile, filename)
    n += 1
    filename = "#{stem}_#{n}#{ext}"
  end
  filename
end

#mimetype ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 63

def mimetype
  # the mimetype file must be the first file in the archive
  # it must be ASCII, uncompressed, and unencrypted
  'application/epub+zip'
end

#ncx ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 116

def ncx
  xm = Builder::XmlMarkup.new(:indent => 2)
  xm.instruct!
  xm.declare!(:DOCTYPE, :ncx, :PUBLIC, '-//NISO//DTD ncx 2005-1//EN', 'http://www.daisy.org/z3986/2005/ncx-2005-1.dtd')
  xm.ncx('version'=>'2005-1', 'xml:lang'=>'en', 'xmlns'=>'http://www.daisy.org/z3986/2005/ncx/') {
    xm.head {
      xm.meta 'name'=>'dtb:uid', 'content'=>book.ident
      xm.meta 'name'=>'dtb:depth', 'content'=>book.depth
      xm.meta 'name'=>'dtb:totalPageCount', 'content'=>0
      xm.meta 'name'=>'dtb:maxPageNumber', 'content'=>0
    }
    
    xm.docTitle {
      xm.text book.full_title
    }
    
    xm.docAuthor {
      xm.text book.author
    }
    
    xm.navMap {
      play_order = 1
      
      # also frontmatter, backmatter
      book.chapters.each do |chapter|
        xm.navPoint('class'=>'chapter', 'id'=>chapter.epub_id, 'playOrder'=>play_order) {
          xm.navLabel {
            xm.text chapter.title
          }
          xm.content 'src'=>chapter.epub_output_file
        }
        play_order += 1
      end
    }
  }
end

#opf ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 79

def opf
  xm = Builder::XmlMarkup.new(:indent => 2)
  xm.instruct!
  xm.package('version'=>'2.0', 'xmlns'=>'http://www.idpf.org/2007/opf', 'unique-identifier'=>'BookId') {
    
    xm.metadata('xmlns:dc'=>'http://purl.org/dc/elements/1.1/', 'xmlns:opf'=>'http://www.idpf.org/2007/opf') {
      # required elements
      xm.dc :title, book.full_title
      xm.dc :language, book.language
      xm.dc :identifier, book.url, ident_options('opf:scheme'=>'URL') if book.url
      xm.dc :identifier, book.isbn, ident_options('opf:scheme'=>'ISBN') if book.isbn            
      
      # optional elements
      xm.dc :creator, book.author, 'opf:role'=>'aut' if book.author
    }
    
    xm.manifest {
      book.chapters.each{|chapter| xm.item 'id'=>chapter.epub_id, 'href'=>chapter.epub_output_file, 'media-type'=>'application/xhtml+xml'}
      # also frontmatter, backmatter
      xm.item 'id'=>'stylesheet', 'href'=>'css/book.css', 'media-type'=>'text/css'
      manifest_entries.each do |entry|
        xm.item 'id'=>entry.xml_id, 'href'=>entry.file_name, 'media-type'=>entry.mime_type
      end
      # xm.item 'id'=>'myfont', 'href'=>'css/myfont.otf', 'media-type'=>'application/x-font-opentype'
      xm.item 'id'=>'ncx', 'href'=>'book.ncx', 'media-type'=>'application/x-dtbncx+xml'
    }
    
    xm.spine('toc'=>'ncx') {
      book.chapters.each{|chapter| xm.itemref 'idref'=>chapter.epub_id}
    }
    
    # xm.guide {
    #   xm.reference 'type'='loi', 'title'=>'List of Illustrations', 'href'=>'appendix.html#figures'
    # }
  }
end

#stylesheet ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 225

def stylesheet
  # This is a start, but needs work.
  %q{|@page {
     |  margin-top: 0.8em;
     |  margin-bottom: 0.8em;}
     |
     |body {
     |  margin-left: 1em;
     |  margin-right: 1em;
     |  padding: 0;}
     |
     |h2 {
     |  padding-top:0;
     |  display:block;}
     |
     |p {
     |  margin-top: 0.3em;
     |  margin-bottom: 0.3em;
     |  text-indent: 1.0em;
     |  text-align: justify;}
     |
     |body > p:first-child {text-indent: 0}
     |div.text p:first-child {text-indent: 0}
     |
     |blockquote p, li p {
     |  text-indent: 0.0em;
     |  text-align: left;}
     |
     |div.chapter {padding-top: 3.0em;}
     |div.part {padding-top: 3.0em;}
     |h3.section_title {text-align: center;}
     |}.strip_margin
end

#write_chapter(chapter, zipfile) ⇒ Object 



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# File 'lib/bindery/formats/epub.rb', line 153

def write_chapter(chapter, zipfile)
  save_options = Nokogiri::XML::Node::SaveOptions
  File.open(chapter.file, 'r:UTF-8') do |ch_in|
    doc = Nokogiri.HTML(ch_in.read)
    include_images(doc, zipfile) if chapter.include_images?
    zipfile.get_output_stream(chapter.epub_output_file) do |ch_out|
      if chapter.body_only?
        # FIXME: must HTML-escape the chapter title
        ch_out.write %{|<?xml version="1.0" encoding="UTF-8" ?>
                       |<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
                       |<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
                       |<head>
                       |  <meta http-equiv="Content-Type" content="application/xhtml+xml; charset=utf-8" />
                       |  <title>#{chapter.title}</title>
                       |  <link rel="stylesheet" href="css/book.css" type="text/css" />
                       |</head>
                       |}.strip_margin
        ch_out.write doc.at('body').serialize(:save_with => (save_options::AS_XHTML | save_options::NO_DECLARATION))
        ch_out.write %{|</html>
                       |}.strip_margin
      else
        ch_out.write doc.serialize(:save_with => save_options::AS_XHTML)
      end
    end
  end
end

#zip_dir_exists?(zipfile, dirname) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/bindery/formats/epub.rb', line 268

def zip_dir_exists?(zipfile, dirname)
  dirname = "#{dirname}/" unless dirname =~ %r{/$}
  zipfile.entries.any?{|e| e.directory? && e.name == dirname}
end

#zip_file_exists?(zipfile, filename) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/bindery/formats/epub.rb', line 273

def zip_file_exists?(zipfile, filename)
  zipfile.entries.any?{|e| e.name == filename}
end