CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3r
Sam
Sam

Reputation: 565

R client for a remote Ruby on Rails environment

I will try to explain as clearly as possible my issue.

My company has a Ruby on Rails 3 environment. Guys in charge of the RoR environment spent a lot of time on it and made a great job at building a complex information system.

I am an R user, and I would like to take advantage of the Rails layer they developped.

Is there an easy way for a local R instance to connect to the remote Rails server and use its set of functions to retrieve data ? The development team has total control over the Rails environment/server and I can easily interact with them, but they do not know much about R.

I have been looking at RSRuby, Rserve (Rserve-Ruby-client), Resque, RinRuby... but to my limited understanding, it always seems to be Ruby being an R client.

For R using Ruby, apart from local call to the Ruby console (not Rails) such as x=system('ruby calc.rb', intern=TRUE) . I could not find much.

Would stackoverflow community has some suggestion there ?

Upvotes: 1

Views: 592

Answers (3)

Harish Shetty
Harish Shetty

Reputation: 64363

I am assuming R can invoke REST based services. Your rails team can expose the RAILS server functions using the REST interface. In Rails 3, it is easy to convert a HTML service to a REST(XML/JSON) service.

Additional Notes based on user comment

Let us assume that you have a Users controller with an index action to return a list of users in a HTML document.

class UsersController
  def index
    @users = User.all
    respond_with(@users)    
  end
end

To enable the index service to return the user list in XML/JSON format:

class UsersController

  respond_to :html, :xml, :json 

  def index
    @users = User.all
    respond_with(@users)    
  end
end

Now

  • http://host/users.xml returns a XML document

  • http://host/users.json returns a JSON structure

The XML/JSON wire format is fixed by rails. You don't need to create a template for this. You should work with your rails team to get the XML/JSON document structure. A typical XML document might look like this:

http://host/orders/1

<?xml version="1.0" encoding="UTF-8"?>
<order>
  <client-id type="integer">1</client-id>
  <created-at type="datetime">2011-04-03</created-at>
  <id type="integer">1</id>
  <updated-at type="datetime">2011-04-03</updated-at>
  ...
</order>

Upvotes: 4

Carl Witthoft
Carl Witthoft

Reputation: 21502

The advice from other blogs, e.g. http://www.r-bloggers.com/calling-ruby-perl-or-python-from-r/ , seems to be to go ahead and use system calls. What you're hoping for is basically an interpreter, which is a big job (and usually doesn't work well :-( ). I'd recommend you collect the basic system calls you'll be using regularly and put them into an R-function. that way, you only need to type
> My.new.data <- tellRuby(data_to_get) and your "tellRuby" function can call the dbase and return the desired data.

Upvotes: 0

Keith Gaddis
Keith Gaddis

Reputation: 4113

I don't really know anything about R either, but it seems like you're likely to have the ability to load a remote URL and process XML, which means you could use activeresource to get data out of their system, and that's really all it takes. A rails system isn't any different from any other web-based system at the application boundary (web server). You could also get data back from Rails in JSON or any other format that's friendly to R if your Rails developers are willing to add those outputs (most of which you can get for free with one gem or another.)

Upvotes: 3

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