Simple rack PHP server rake task

Rakefile

#
# Sample rake task for starting a Thin rack server for a PHP application (like
# Wordpress or Drupal or whatever).
#
# Requires php-cgi be available on path (I used homebrew on my mac to install 
# php since it doesn't come pre-installed) and gems 'thin', 'rack' and 
# 'rack-legacy'.
# 
BASE_PATH = File.expand_path(File.dirname(__FILE__))
SRC_PATH = File.join(BASE_PATH, 'src')

SERVER_PORT = '3000'
SERVER_HOST = '0.0.0.0'

desc 'Starts a thin rack server to dish out the src directory'
task :server do
  require 'thin'
  require 'rack-legacy' 
  require 'rack/legacy/cgi'
  require 'rack/legacy/php'

  # Handler to sort of simulate Apache's DirectoryIndex directive
  class DirectoryIndex
    def initialize(app, root=Dir.pwd, files=[])
      @app = app
      @root = root
      @files = files
    end

    def call(env)
      if env['PATH_INFO'] =~ /\/$/
        path = File.join(@root, Rack::Utils.unescape(env['PATH_INFO']))
        if File.directory?(path)
          @files.each do |file|
            if File.exists?(File.join(path, file))
              env['PATH_INFO'] = env['PATH_INFO'] + file
              break
            end
          end
        end
      end
      @app.call(env)
    end
  end

  app = Rack::Builder.new do
    use DirectoryIndex, SRC_PATH, ['index.php', 'index.html', 'index.htm']

    use Rack::ShowExceptions
    use Rack::Legacy::Php, SRC_PATH
    use Rack::Legacy::Cgi, SRC_PATH

    run Rack::Directory.new(SRC_PATH)
  end
  
  Rack::Handler::Thin.run(app, { :Host => SERVER_HOST, :Port => SERVER_PORT })
end