How to run Ruby On Rails on Google AppEngine

There is a tutorial https://gist.github.com/671792 by John Woodell,
however it was costumed running in linux environment,
and there is some slightly changes they didnt update their tutorial script,
the script will not work out of box,
So in here i am making a post, especially benefit users who is using Windows, since i am doing this in Windows 7 environment.

PS : i assume u have already had a google app engine account, if u dont, do some bing or google and get one

Specially thanks for the help from Andrew Myers.

1) Install Java Development Kit  6 (JDK6)
make sure you have similar stuff show up in your windows command prompt

>java -version
java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b07)
Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)
>javac -version
javac 1.6.0_21

2)  Install AppEngine Java SDK http://code.google.com/appengine/downloads.html
Download the  SDK, and make sure you put the "bin" directory into your system "Path"

3) Install Ruby 1.8.7 , not JRuby
Download it http://www.ruby-lang.org/en/downloads/, and install it,
make sure you associate *.rb to be run by ruby  (for windows install, there is the check box)

again open a new command prompt, you should have something like this

>ruby -v
ruby 1.8.7 (2010-08-16 patchlevel 302) [i386-mingw32]
>gem -v
1.3.7

4) Install plugins for ruby
Make sure you open a command prompt as administrator

and type in the following one by one

gem install google-appengine

gem install rails -v "2.3.10"

gem install rails_dm_datastore

gem install activerecord-nulldb-adapter

each one will take a while, so be patient..

5) Make a directory to contain you ROR application

mkdir railsv1
cd railsv1

Or you can use GUI to do it.

6) Copy the code below, save it to a file, for example rails2310_appengine.rb

#!/usr/bin/ruby
#
# Copyright:: Copyright 2009 Google Inc.
# Original Author:: John Woodell (mailto:woodie@google.com)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

require 'fileutils'
require 'open-uri'

def composite(source, fragment, index = nil, trim = nil)
  File.open(source, 'r+') do |f|
    lines = f.readlines
    lines = lines[0..trim] unless trim.nil?
    f.pos = 0
    File.open(fragment) do |z|
      section = z.readlines
      if index and index.size < lines.size
        f.print lines[0,index] + section + lines[index..-1]
      else
        f.print lines + section
      end
    end
    f.truncate(f.pos)
  end
  FileUtils.rm fragment
end

def download_file(path, url)
  open(url) do |r|
    FileUtils.mkpath(File.dirname(path))
    open(path,"w"){|f| f.write(r.read) }
  end
end
SET_CMD = RUBY_PLATFORM.include?('mswin32') ? 'set' : 'export'
MORE_GEMS = 'rails_appengine/active_support_vendored'
FILE_BASE = 'http://appengine-jruby.googlecode.com/hg/demos/rails2/'
MOD_FILES = %w{ app/controllers/rails/info_controller.rb public/favicon.ico
                config.ru config/boot_rb config/environment_rb
                config/initializers/gae_init_patch.rb config/database.yml
                script/console.sh script/publish.sh script/server.sh }
# Install Rails 2.3.10
FileUtils.touch 'config.ru'
gemsrc = ARGV[0].eql?('tiny_ds') ? 'Gemfile_td' : 'Gemfile'
download_file("Gemfile", "#{FILE_BASE}#{gemsrc}")
download_file("gems_2310", "#{FILE_BASE}gems_2310")
composite('Gemfile', 'gems_2310', nil, -2)
FileUtils.mkdir_p 'WEB-INF'
download_file("WEB-INF/app.yaml", "#{FILE_BASE}WEB-INF/app.yaml")
system 'appcfg.rb bundle --update .'
# Remove dups and generate Rails app
# Generate rails, and skip APIs to escape the shell
system "rails _2.3.10_ ."
# Fetch configuration files
FileUtils.mkdir_p 'app/controllers/rails'
MOD_FILES.each { |path| download_file(path, "#{FILE_BASE}#{path}") }
if ARGV[0].eql? 'tiny_ds'
  download_file("config/environment_rb", "#{FILE_BASE}config/environment_td")
end
# Merge configs into boot.rb
composite('config/boot.rb', 'config/boot_rb', 108)
# Merge configs into environment.rb
composite('config/environment.rb', 'config/environment_rb', 30)
# install the nulldb adapter
system 'ruby script/plugin install http://svn.avdi.org/nulldb/trunk/'
puts "##"
puts "## Now type 'dev_appserver.rb .'"
puts "##"


and run it, e.g  ruby rails2310_appengine.rb, then you should see something like this: