Batch publish markdown files as HTML

publish.rb

#! /usr/bin/env ruby 

# Given a directory with several chapter subdirectories each containing a markdown file
# And a header and footer file in a directory called 00-shared,
# When I run ./publish -p html
# I should get individual html files from the markdown
# And I should get a book.html file with everything compiled together

# Example layout (cribbed from github.com/progit/progit):
#
# 00-shared
#    \--- header.html
#    \--- footer.html
# 01-chapter1
#    \--- 01-chapter1.markdown
# 02-chapter2
#    \--- 01-chapter2.markdown

require 'rubygems'
require 'clap'

FORMATS = ["html"]

if ARGV.empty?
  puts "usage: [-p format]"
end

class Publish
  HEADER = "00-shared/header.html"
  FOOTER = "00-shared/footer.html"
  CHAPTER_FILES = Dir.glob("*").collect{|g|
    next if File.file?(g)
    Dir.foreach(g).collect{|i_g|
      next if i_g.match(/markdown/).nil?
      "#{g}/#{i_g}"
    }
  }.flatten!.compact!

  CHAPTER_HTML = CHAPTER_FILES.collect{|f| f.gsub('markdown','html')}
  
  def self.publish(format)
    puts "Cleaning old files...\n"
    clean
    puts "Converting individual chapters....\n\n"
    convert_chapters
    if format == "html"
      puts "\nGenerating HTML Book"
      File.delete('book.html') if File.exists?('book.html')
      CHAPTER_HTML.collect{|f|
        puts "Collecting #{f}\n"
        system <<-HTML
cat #{HEADER} >> book.html && cat #{f} >> book.html && cat #{FOOTER} >> book.html
        HTML
      }
    end
  end
  
  def self.convert_chapters
    CHAPTER_FILES.each do |chapter_file|
      puts "Converting #{chapter_file}\n"
      chapter_html = chapter_file.gsub('markdown','html')
      system <<-MARKITDOWN
markdown #{chapter_file} > #{chapter_html}
      MARKITDOWN
    end
  end

  def self.clean
    CHAPTER_FILES.each{|f| File.delete(f.gsub('markdown','html'))}
  end

end

args = Clap.run ARGV,
    "-p" => lambda{|format| Publish.publish(format) if FORMATS.include?(format)}