bmc/fixepub.rb

## fixepub.rb
#!/usr/bin/env ruby
#
# Fix an EPUB document generated by Pandoc to have a title page.
#
# Usage: fixepub epub_in epub_out cover_png
#
# Only supports PNG at the moment, but easily hacked to support JPEG.
#
# Requires these gems:
#
# - rubyzip
# ---------------------------------------------------------------------------

require 'rexml/document'
require 'rubygems'
require 'zip/zipfilesystem'
require 'zip/zip'
require 'tempfile'
require 'fileutils'

# Unzip a zip file to a temporary directory. Assumes the directory already
# exists.
def unzip(zip_file, dir)
  puts "Unzipping #{zip_file}"
  zip = Zip::ZipFile.open(zip_file)
  Zip::ZipFile.foreach(zip_file) do |entry|
    file_path = File.join(dir, entry.to_s)
    if not File.exists? file_path
      # Make the directory
      FileUtils.mkdir_p File.dirname(file_path)
    end
    zip.extract(entry, file_path)
  end
end

# Zip the contents of a directory into a new zip file. Deletes the zip file
# if it already exists.
def zip(zip_file, dir)
  FileUtils.rm_f(zip_file)
  puts("Creating #{File.expand_path(zip_file)}")
  zip = Zip::ZipFile.open(zip_file, Zip::ZipFile::CREATE)
  Dir[File.join(dir, '**', '*').to_s].each do |path|
    short_path = path[dir.length+1..-1]
    if File.directory? path
      zip.mkdir(short_path)
    else
      zip.add(short_path, path)
    end
  end
  zip.close
end

# Fix the epub distribution, adding a cover image and editing various
# things.
def fix_epub(unpacked_dir, cover_image)
  # Copy the cover image and XHTML wrapper into place.

  puts("Copying #{cover_image}")
  FileUtils.mkdir_p File.join(unpacked_dir, 'images')
  FileUtils.cp cover_image, File.join(unpacked_dir, 'images', 'cover.png')

  puts("Generating cover XHTML")
  cover_xhtml_file = File.open(File.join(unpacked_dir, 'cover.xhtml'), 'w')
  cover_xhtml = <<COVER_XHTML
<!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">
<head>
<title>Cover</title>
<style type="text/css"> img { max-width: 100%; } </style>
</head>
<body>
<div id="cover-image">
<img src="images/cover.png" alt="Rebel by Default"/>
</div>
</body>
</html>
COVER_XHTML
  cover_xhtml_file.write(cover_xhtml)
  cover_xhtml_file.close

  # Edit the OPF file.

  content_opf = File.join(unpacked_dir, 'content.opf')
  puts("Editing #{content_opf}")
  doc = REXML::Document.new(File.new(content_opf))

  # Add the cover to the metadata.
  metadata = REXML::XPath.first(doc, '//package/metadata')
  metadata.add_element 'meta', {'name' => 'cover', 'content' => 'cover-image'}

  # Add cover to the manifest
  manifest = REXML::XPath.first(doc, '//package/manifest')
  manifest.add_element 'item', {'id' => 'cover',
                                'href' => 'cover.xhtml',
                                'media-type' => 'application/xhtml+xml'}
  manifest.add_element 'item', {'id' => 'cover-image',
                                'href' => 'images/cover.png',
                                'media-type' => 'image/png'}

  # Add the cover to the spine.
  spine = REXML::XPath.first(doc, '//package/spine')
  cover_ref = REXML::Element.new 'itemref'
  cover_ref.attributes['idref'] = 'cover'
  cover_ref.attributes['linear'] = 'no'
  spine[0,0] = cover_ref

  # Delete the title page from the spine
  title_page = REXML::XPath.first(spine, "//itemref[@idref='title_page']")
  if not title_page
    puts "WARNING: No title page xref found in spine."
  else
    spine.delete(title_page)
  end

  # Add the guide section.
  guide = doc.root.add_element 'guide'
  guide.add_element 'reference', {'href' => 'cover.xhtml',
                                  'type' => 'cover',
                                  'title' => 'cover'}
  f_opf = File.open(content_opf, 'w')
  f_opf.write(doc.to_s)
  f_opf.close
end

# ---------------------------------------------------------------------------
# Main logic

# ---------------------------------------------------------------------------

if ARGV.length != 3
  abort("Usage: #{$0} epub_in epub_out cover_image")
end

PATH_IN = ARGV[0]
PATH_OUT = ARGV[1]
COVER_IMAGE = ARGV[2]

# Create temporary directory and arrange to have it go away on exit.
temp_dir = File.join(Dir.tmpdir, "book" + $$.to_s)
Dir.mkdir temp_dir
at_exit do
  puts("Removing #{temp_dir}")
  FileUtils.rm_rf temp_dir
end

# Unzip the epub file.
unzip PATH_IN, temp_dir

# Fix the unpacked epub distribution
fix_epub(temp_dir, COVER_IMAGE)

# Zip it all back up again.
zip PATH_OUT, temp_dir

exit(0)
	#!/usr/bin/env ruby
	#
	# Fix an EPUB document generated by Pandoc to have a title page.
	#
	# Usage: fixepub epub_in epub_out cover_png
	#
	# Only supports PNG at the moment, but easily hacked to support JPEG.
	#
	# Requires these gems:
	#
	# - rubyzip
	# ---------------------------------------------------------------------------

	require 'rexml/document'
	require 'rubygems'
	require 'zip/zipfilesystem'
	require 'zip/zip'
	require 'tempfile'
	require 'fileutils'

	# Unzip a zip file to a temporary directory. Assumes the directory already
	# exists.
	def unzip(zip_file, dir)
	puts "Unzipping #{zip_file}"
	zip = Zip::ZipFile.open(zip_file)
	Zip::ZipFile.foreach(zip_file) do \|entry\|
	file_path = File.join(dir, entry.to_s)
	if not File.exists? file_path
	# Make the directory
	FileUtils.mkdir_p File.dirname(file_path)
	end
	zip.extract(entry, file_path)
	end
	end

	# Zip the contents of a directory into a new zip file. Deletes the zip file
	# if it already exists.
	def zip(zip_file, dir)
	FileUtils.rm_f(zip_file)
	puts("Creating #{File.expand_path(zip_file)}")
	zip = Zip::ZipFile.open(zip_file, Zip::ZipFile::CREATE)
	Dir[File.join(dir, '*', '').to_s].each do \|path\|
	short_path = path[dir.length+1..-1]
	if File.directory? path
	zip.mkdir(short_path)
	else
	zip.add(short_path, path)
	end
	end
	zip.close
	end

	# Fix the epub distribution, adding a cover image and editing various
	# things.
	def fix_epub(unpacked_dir, cover_image)
	# Copy the cover image and XHTML wrapper into place.

	puts("Copying #{cover_image}")
	FileUtils.mkdir_p File.join(unpacked_dir, 'images')
	FileUtils.cp cover_image, File.join(unpacked_dir, 'images', 'cover.png')

	puts("Generating cover XHTML")
	cover_xhtml_file = File.open(File.join(unpacked_dir, 'cover.xhtml'), 'w')
	cover_xhtml = <<COVER_XHTML
	<!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">
	<head>
	<title>Cover</title>
	<style type="text/css"> img { max-width: 100%; } </style>
	</head>
	<body>
	<div id="cover-image">
	<img src="images/cover.png" alt="Rebel by Default"/>
	</div>
	</body>
	</html>
	COVER_XHTML
	cover_xhtml_file.write(cover_xhtml)
	cover_xhtml_file.close

	# Edit the OPF file.

	content_opf = File.join(unpacked_dir, 'content.opf')
	puts("Editing #{content_opf}")
	doc = REXML::Document.new(File.new(content_opf))

	# Add the cover to the metadata.
	metadata = REXML::XPath.first(doc, '//package/metadata')
	metadata.add_element 'meta', {'name' => 'cover', 'content' => 'cover-image'}

	# Add cover to the manifest
	manifest = REXML::XPath.first(doc, '//package/manifest')
	manifest.add_element 'item', {'id' => 'cover',
	'href' => 'cover.xhtml',
	'media-type' => 'application/xhtml+xml'}
	manifest.add_element 'item', {'id' => 'cover-image',
	'href' => 'images/cover.png',
	'media-type' => 'image/png'}

	# Add the cover to the spine.
	spine = REXML::XPath.first(doc, '//package/spine')
	cover_ref = REXML::Element.new 'itemref'
	cover_ref.attributes['idref'] = 'cover'
	cover_ref.attributes['linear'] = 'no'
	spine[0,0] = cover_ref

	# Delete the title page from the spine
	title_page = REXML::XPath.first(spine, "//itemref[@idref='title_page']")
	if not title_page
	puts "WARNING: No title page xref found in spine."
	else
	spine.delete(title_page)
	end

	# Add the guide section.
	guide = doc.root.add_element 'guide'
	guide.add_element 'reference', {'href' => 'cover.xhtml',
	'type' => 'cover',
	'title' => 'cover'}
	f_opf = File.open(content_opf, 'w')
	f_opf.write(doc.to_s)
	f_opf.close
	end

	# ---------------------------------------------------------------------------
	# Main logic

	# ---------------------------------------------------------------------------

	if ARGV.length != 3
	abort("Usage: #{$0} epub_in epub_out cover_image")
	end

	PATH_IN = ARGV[0]
	PATH_OUT = ARGV[1]
	COVER_IMAGE = ARGV[2]

	# Create temporary directory and arrange to have it go away on exit.
	temp_dir = File.join(Dir.tmpdir, "book" + $$.to_s)
	Dir.mkdir temp_dir
	at_exit do
	puts("Removing #{temp_dir}")
	FileUtils.rm_rf temp_dir
	end

	# Unzip the epub file.
	unzip PATH_IN, temp_dir

	# Fix the unpacked epub distribution
	fix_epub(temp_dir, COVER_IMAGE)

	# Zip it all back up again.
	zip PATH_OUT, temp_dir

	exit(0)