ConvertToStandAloneHTML.rb

module ConvertToStandAloneHTML

  EMPTY_LINE = /^\s*$/

  #
  # This is the only public method.
  # Please use like this.
  #
  #  Pack[ "Some HTML string to be converted." ]
  def self.[] contents

    image_tag = /<img\s*.*?\s*src="(.*?\.png)".*?>/i

    ret = contents.each_line.map do |l|
      case l
      when /<script\s*.*\s*src="(.*?\.js)".*>/
        "<script type='text/javascript'>#{ File.read( "./#{$1}" ) }</script>"

      when /<link\s*.*\s*href="(.*?\.css)".*>/
        css_contents = File.read( "./#{$1}" )
        "<style type='text/css'>#{ source_css_images( css_contents ) }</style>"

      when image_tag

        puts "SOURCE: #{l}"
        l.gsub( image_tag ) do |matched|
          data = File.open("./#{$1}", "r" ){ |f| f.binmode.read }
          encoded = [data].pack( "m*" ).split("\n").join("")
          matched.gsub( /src=".*"/, "src='data:image/png;base64,#{encoded}'" )
        end

      when EMPTY_LINE then nil
      else l
      end rescue l
    end.compact.join("\n")

    ret
  end

  def self.source_css_images css_contents

    image_url = /^.*:\s*url\(\s*["']images\/(.*?\.png)["']\).*;.*$/

    css_contents.each_line.map do |l|
      case l
      when image_url

        l.gsub( image_url ) do |matched|
          data = File.open( Dir.glob( "**/#{$1}" ).first, "r" ){ |f| f.binmode.read }
          encoded = [data].pack( "m*" ).split("\n").join("")
          matched.gsub( /url\(.*?\)\s*;.*$/, "url(data:image/png;base64,#{encoded});" )
        end

      when EMPTY_LINE then nil
      else l
      end rescue l
    end.compact.join("\n")
  end
  private_class_method :source_css_images

end