Merge pull request #8348 from danchoi/master

Kindle ebook generation with working section navigation

guides/Rakefile

@@ -13,6 +13,12 @@ namespace :guides do
 
     desc "Generate .mobi file. The kindlegen executable must be in your PATH. You can get it for free from http://www.amazon.com/kindlepublishing"
     task :kindle do
+      unless `kindlerb -v 2> /dev/null` =~ /kindlerb 0.1.1/  
+        abort "Please `gem install kindlerb`"
+      end
+      unless `convert` =~ /convert/  
+        abort "Please install ImageMagick`"
+      end
       ENV['KINDLE'] = '1'
       Rake::Task['guides:generate:html'].invoke
     end

guides/rails_guides/generator.rb

@@ -112,11 +112,9 @@ def check_for_kindlegen
     end
 
     def generate_mobi
-      opf = "#{output_dir}/rails_guides.opf"
+      require 'rails_guides/kindle'
       out = "#{output_dir}/kindlegen.out"
-
-      system "kindlegen #{opf} -o #{mobi} > #{out} 2>&1"
-      puts "Guides compiled as Kindle book to #{mobi}"
+      Kindle.generate(output_dir, mobi, out)
       puts "(kindlegen log at #{out})."
     end
 

guides/rails_guides/kindle.rb

+#!/usr/bin/env ruby
+
+unless `which kindlerb` 
+  abort "Please gem install kindlerb"
+end
+
+require 'nokogiri'
+require 'fileutils'
+require 'yaml'
+require 'date'
+
+module Kindle
+  extend self
+
+  def generate(output_dir, mobi_outfile, logfile)
+    output_dir = File.absolute_path(output_dir)
+    Dir.chdir output_dir do 
+      puts "=> Using output dir: #{output_dir}"
+      puts "=> Arranging html pages in document order"
+      toc = File.read("toc.ncx")
+      doc = Nokogiri::XML(toc).xpath("//ncx:content", 'ncx' => "http://www.daisy.org/z3986/2005/ncx/")
+      html_pages = doc.select {|c| c[:src]}.map {|c| c[:src]}.uniq
+     
+      generate_front_matter(html_pages)
+
+      generate_sections(html_pages)
+
+      generate_document_metadata(mobi_outfile)
+
+      puts "Creating MOBI document with kindlegen. This make take a while."
+      cmd = "kindlerb . > #{File.absolute_path logfile} 2>&1"
+      puts cmd
+      system(cmd)
+      puts "MOBI document generated at #{File.expand_path(mobi_outfile, output_dir)}"
+    end
+  end
+
+  def generate_front_matter(html_pages)
+    frontmatter = []
+    html_pages.delete_if {|x| 
+      if x =~ /(toc|welcome|credits|copyright).html/
+        frontmatter << x unless x =~ /toc/
+        true
+      end
+    }
+    html = frontmatter.map {|x|
+      Nokogiri::HTML(File.open(x)).at("body").inner_html
+    }.join("\n")
+
+    fdoc = Nokogiri::HTML(html)
+    fdoc.search("h3").each do |h3|
+      h3.name = 'h4'
+    end
+    fdoc.search("h2").each do |h2| 
+      h2.name = 'h3'
+      h2['id'] = h2.inner_text.gsub(/\s/, '-')
+    end
+    add_head_section fdoc, "Front Matter"
+    File.open("frontmatter.html",'w') {|f| f.puts fdoc.to_html}
+    html_pages.unshift "frontmatter.html"
+  end
+
+  def generate_sections(html_pages)
+    FileUtils::rm_rf("sections/")
+    html_pages.each_with_index do |page, section_idx|
+      FileUtils::mkdir_p("sections/%03d" % section_idx)
+      doc = Nokogiri::HTML(File.open(page))
+      title = doc.at("title").inner_text.gsub("Ruby on Rails Guides: ", '')
+      title = page.capitalize.gsub('.html', '') if title.strip == ''
+      File.open("sections/%03d/_section.txt" % section_idx, 'w') {|f| f.puts title}
+      doc.xpath("//h3[@id]").each_with_index do |h3,item_idx|
+        subsection = h3.inner_text
+        content = h3.xpath("./following-sibling::*").take_while {|x| x.name != "h3"}.map {|x| x.to_html}
+        item = Nokogiri::HTML(h3.to_html + content.join("\n"))
+        item_path = "sections/%03d/%03d.html" % [section_idx, item_idx] 
+        add_head_section(item, subsection)
+        item.search("img").each do |img|
+          img['src'] = "#{Dir.pwd}/#{img['src']}"
+        end
+        item.xpath("//li/p").each {|p| p.swap(p.children); p.remove}
+        File.open(item_path, 'w') {|f| f.puts item.to_html}
+      end
+    end
+  end
+
+  def generate_document_metadata(mobi_outfile)
+    puts "=> Generating _document.yml"
+    x = Nokogiri::XML(File.open("rails_guides.opf")).remove_namespaces!
+    cover_jpg = "#{Dir.pwd}/images/rails_guides_kindle_cover.jpg"
+    cover_gif = cover_jpg.sub(/jpg$/, 'gif')
+    puts `convert #{cover_jpg} #{cover_gif}`
+    document = {
+      'doc_uuid' => x.at("package")['unique-identifier'],
+      'title' => x.at("title").inner_text.gsub(/\(.*$/, " v2"),
+      'publisher' => x.at("publisher").inner_text,
+      'author' => x.at("creator").inner_text,
+      'subject' => x.at("subject").inner_text,
+      'date' => x.at("date").inner_text,
+      'cover' => cover_gif,
+      'masthead' => nil,
+      'mobi_outfile' => mobi_outfile
+    }
+    puts document.to_yaml
+    File.open("_document.yml", 'w'){|f| f.puts document.to_yaml}
+  end
+
+  def add_head_section(doc, title)
+    head = Nokogiri::XML::Node.new "head", doc
+    title_node = Nokogiri::XML::Node.new "title", doc
+    title_node.content = title
+    title_node.parent = head
+    css = Nokogiri::XML::Node.new "link", doc
+    css['rel'] = 'stylesheet'
+    css['type'] = 'text/css'
+    css['href'] = "#{Dir.pwd}/stylesheets/kindle.css"
+    css.parent = head
+    doc.at("body").before head
+  end
+end

guides/source/kindle/rails_guides.opf.erb

@@ -32,7 +32,7 @@
 
   <item id="toc" media-type="application/x-dtbncx+xml" href="toc.ncx" />
 
-  <item id="cover" media-type="image/jpeg" href="images/rails_guides_kindle_cover.jpg"/>
+  <item id="cover" media-type="image/jpg" href="images/rails_guides_kindle_cover.jpg"/>
 </manifest>
 
 <spine toc="toc">