README.rdoc

Rails 2.3.11 on App Engine (DataMapper)¶ ↑

Do not use rvm (or install and run from JRuby). The google-appengine gem must install into your system MRI. The appengine-sdk gem includes a complete Java app server. We bootstrap Java from MRI, then your app runs inside a servlet container (with access to all the APIs) using the version of JRuby installed into each app.

We assumed Rails 2 would never work without rubygems, and we committed to gem bunlder for JRuby on App Engine, so we were waiting for Rails 3. Fortunately, Takeru Sasaki was able to patch the Rails 2.3.x calls to rubygems, and now we have it working. Rails 2.3.x currently spins up several seconds faster than Rails 3, and just a few seconds behind Sinatra.

See the TInyDS version also: gist.github.com/gists/269075

Install the Development Environment¶ ↑

One meta-gem provides the development environment

sudo gem install google-appengine

Install Rails 2.3.11 with required patches¶ ↑

Install some gems you’ll need

sudo gem install rails -v "2.3.11"
sudo gem install rails_dm_datastore
sudo gem install activerecord-nulldb-adapter

Create a folder for your app

mkdir rails_app; cd rails_app

Download and run the setup script

curl -O http://appengine-jruby.googlecode.com/hg/demos/rails2/rails2311_appengine.rb
ruby rails2311_appengine.rb

Working with Your Rails App¶ ↑

Start development server

./script/server.sh

Open local console

./script/console.sh

Publish to production

./script/publish.sh

Support for generators¶ ↑

We disable rubygems in the development environment, and the generators from Rails 2 perform various Gem dependency checks that are too difficult to patch, so we run the generators from the MRI. We also use Josh Moore’s rails_dm_datastore integration plugin.

Generate a restful controller and add it to config/routes.rb

./script/generate scaffold contact title:string summary:text \
birthday:date url:string address:string phone:string -f --skip-migration

Generate a model for DataMapper

./script/generate dd_model contact title:string summary:text \
birthday:date url:link address:postal_address phone:phone_number -f

You’ve created a RESTful controller, and a DataMapper model

contact.rb

class Contact
  include DataMapper::Resource
  storage_names[:default] = "Contact"

  property :id,       Serial
  property :title,    String,        :required => true, :length => 500
  property :summary,  Text,          :required => true, :lazy => false
  property :birthday, Date,          :required => true
  property :url,      Link,          :required => true
  property :address,  PostalAddress, :required => true
  property :phone,    PhoneNumber,   :required => true
  timestamps :at
end

Data types: http://code.google.com/appengine/docs/java/datastore/entities.html#Properties_and_Value_Types