How do I expose data in a JSON format through a web service using Rails?

Question

Is there an easy way to return data to web service clients in JSON using Rails?

Answer 1

Rails resource gives a RESTful interface for your model. Let's see.

Model

class Contact < ActiveRecord::Base
  ...
end

Routes

map.resources :contacts

Controller

class ContactsController < ApplicationController
  ...
  def show
    @contact = Contact.find(params[:id]

    respond_to do |format|
      format.html 
      format.xml {render :xml => @contact}
      format.js  {render :json => @contact.json}
    end
  end
  ...
end

So this gives you an API interfaces without the need to define special methods to get the type of respond required

Eg.

/contacts/1 # Responds with regular html page

/contacts/1.xml # Responds with xml output of Contact.find(1) and its attributes

/contacts/1.js # Responds with json output of Contact.find(1) and its attributes

Answer 2

http://wiki.rubyonrails.org/rails/pages/HowtoGenerateJSON