Rails 2.3.5 on App Engine with DataMapper

README.rdoc

Rails 2.3.5 on App Engine (DataMapper)¶ ↑

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 2.3.5 calls to rubygems, and now we have it working. Rails 2.3.5 currently spins up several seconds faster than Rails 3, and just a few seconds behind Sinatra.

See the TinyDS version also: gist.github.com/269075

Install the Development Environment¶ ↑

The gems for the development environment include a pre-release appengine-tools gem that provides a pre-release version of jruby-rack.

sudo gem install google-appengine
sudo gem install appengine-tools --pre

Install Rails 2.3.5 with required patches¶ ↑

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/rails2_appengine.rb
ruby rails2_appengine.rb

Working with Your Rails App¶ ↑

Start development server

dev_appserver.rb .

Open local console

appcfg.rb run script/console

Publish to production

appcfg.rb update .

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.

sudo gem install rails rails_dm_datastore
sudo gem install activerecord-nulldb-adapter

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

./script/generate scaffold article title:string summary:text \
url:string phone:string -f --skip-migration

Generate a model for DataMapper

./script/generate dm_model article title:string summary:text \
url:link phone:phone_number -f

./script/generate dm_model article title:string summary:text url:string -f

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

article.rb

class Article
  include DataMapper::Resource

  property :id,      Serial
  property :title,   String,        :nullable => false
  property :summary, Text,          :nullable => false
  property :url,     Link,          :nullable => false
  property :phone,   PhoneNumber,   :nullable => false
  timestamps :at
end

If you want to use the XML versions of the generated scaffolds, you must install the dm-serializer gem because DataMapper doesn't generates valid XML. Of course, you have to require the gem somewhere before you models are used.

if someone needs it i got twitter working on APP ENGIEN using the twitter GEM
http://github.com/huemorgan/Twitter-on-GAE
notes:

1. see the Gemfile for the gems that were bundled here.
   the gem versions matter, older versions don't support new fixes for GAE
   new versions of the twitter GEM currently has binary extentions also not supported by GAE.
2. see that you set the right callback url in your twitter account
   it should match the oauth.set_callback_url in the session controller.
3. used DataMapper for models http://gist.github.com/268192
4. built on http://code.google.com/p/appengine-jruby/
5. some valuable info here about bundeling gems and setting up a new project http://code.google.com/p/appengine-jruby/wiki/InstallEverything

How can I migrate appengien storage structure using DataMapper
DataMapper.auto_upgrade! - doesn't seem to work?

No migration needed for trivial things like adding properties. You have to declare a 'property' in DataMapper so it generates accessors and things, but think of the entities themselves as basically hashes.

If you actually have something you want to change on a global level, that's a bit trickier, and would likely require a bit of task queue trickery if you want to do it on an actual live app.

super helpful -- thanks!

I am unable to follow these instructions: When I try publish the application, I get a message complaining that there are too many files. 8500 instead of the 3000 limit. Does anyone know how to overcome this problem?

thanks

no... using the 238 version of the script didn't do the trick. I am still getting the following message when I try to publish the app:

java.io.IOException: Applications are limited to 3000 files, you have 8914.
Unable to update app: Applications are limited to 3000 files, you have 8914.
Please see the logs [/tmp/appcfg2041444326558256837.log] for further information.

I'm guessing that you have do something bad to the Gemfile

Maybe run a 'find' on your app directory and post that as a gist somewhere?

masover: the files listing can be found here: http://gist.github.com/485749

woodie: what is the Gemfile? How can I tackle its problems?

By the way: My application is empty: I didn't change anything after having ran script that created the directory structure.

How to use the Rails 3.0.1 (latest) with app engine??
Is there any other resource coz I googled and couldn't find the exact for Rails 3.

I publish the app and recive an Error: INTERNAL_SERVER_ERROR (500)
on local server runs ok

I publish the app and recive an Error: INTERNAL_SERVER_ERROR (500)
on local server runs ok

Yes. I have same problem