1 rack.duby

import org.jruby.rack.DefaultRackApplicationFactory
import org.jruby.rack.RackApplicationFactory
import org.jruby.rack.RackInitializationException
import org.jruby.rack.RackServletContextListener
import org.jruby.rack.SharedRackApplicationFactory

class AppEngineRackApplicationFactory < DefaultRackApplicationFactory
  def initialize
  end

  def createApplicationObject(runtime)
    createRackServletWrapper(
        runtime, "eval(IO.read('config.ru'), nil, 'config.ru', 1)")
  end

  def createRackServletWrapper(runtime, rackup)
    runtime.evalScriptlet(<<-EOF)
      require 'appengine-rack/boot'
      load 'jruby/rack/boot/rack.rb'
      Rack::Handler::Servlet.new(Rack::Builder.new {( #{rackup}
       )}.to_app)
    EOF
  end
end

class LazyApplicationFactory; implements RackApplicationFactory
  def initialize
  end

  def init(context)
    @context = context
  end

  def real_factory
    throws RackInitializationException
    if @factory.nil?
      @factory = SharedRackApplicationFactory.new(
          AppEngineRackApplicationFactory.new)
      @factory.init(@context)
    end
    @factory
  end

  def newApplication
    throws RackInitializationException
    real_factory.newApplication
  end

  def getApplication
    throws RackInitializationException
    real_factory.getApplication
  end

  def finishedWithApplication(app)
    @factory.finishedWithApplication(app) unless @factory.nil?
  end

  def getErrorApplication
    real_factory.getErrorApplication rescue nil
  end

  def destroy
    @factory.destroy unless @factory.nil?
  end
end

class LazyContextListener < RackServletContextListener
  def newApplicationFactory(context)
    if context.getServerInfo.contains("Development")
      RackApplicationFactory(SharedRackApplicationFactory.new(
        RackApplicationFactory(AppEngineRackApplicationFactory.new)))
    else
      RackApplicationFactory(LazyApplicationFactory.new)
    end
  end
end

2 boot.rb

require 'jruby/rack/booter'

# try to require the bundled environment
begin
  require 'bundler_gems/environment'
rescue LoadError
  # continue
end

module JRuby
  module Rack
    class AppEngineLayout < WebInfLayout
      def app_uri
        @app_uri ||= '/'
      end

      def public_uri
        @public_uri ||= begin
          path = @rack_context.getInitParameter('public.root') || '/public'
          path = "/#{path}" unless path =~ %r{^/}
          path.chomp("/")
        end
      end

      def change_working_directory
        if @rack_context.server_info.include?('Development')
          ENV['RACK_ENV'] = 'development'
        else
          ENV['RACK_ENV'] = 'production'
        end
        super
      end
    end

    class Booter
      def default_layout_class
        AppEngineLayout
      end
    end
  end
end