Rails controller action for an HTML5 cache manifest file.

installer_controller.rb

class InstallerController < ApplicationController
  # Rails controller action for an HTML5 cache manifest file.
  # Generates a plain text list of files that changes
  # when one of the listed files change... 
  # So the client knows when to refresh its cache.
  def cache_manifest
    @files = ["CACHE MANIFEST\n"]

    @files << 'favicon.ico'
    
    @files << './client/sencha/ext-touch.js'
    @files << './client/sencha/resources/css/apple.css'
    
    add_from('./client/views/','*.html')
    add_from('./client/javascripts/','*.js')
    add_from('./client/stylesheets/','*.css')
    add_from('./client/images/','*.png')

    @files << "\nNETWORK:"
    @files << '*'
    
    digest = Digest::SHA1.new
    @files.each do |f|
      actual_file = File.join(Rails.root,'public',f)
      digest << "##{File.mtime(actual_file)}" if File.exist?(actual_file)
    end
    @files << "\n# Modification Digest: #{digest.hexdigest}"
    
    render :text => @files.join("\n"), :content_type => 'text/cache-manifest', :layout => nil
  end

protected
  def add_from(loc,match)
    Dir.glob(File.join(Rails.root,'public',loc, match)) do |file|
      @files << "#{loc}#{File.basename(file)}"
    end
  end
end