Rails makes it really simple to expose your data as XML. It also makes it pretty easy to support any other type of format.

While you can do this in Rails 1.2, this writeup will focus on doing it with Edge Rails.

Assume I have a Project model, a Projects controller, and I’m using a RESTful design…

  rails my_projects_rss --database=sqlite3
  cd my_projects_rss
  ruby scriptgenerate scaffold Project title:string description:string
  rake db:migrate
  ruby script/server

Create a new file at apps/views/projects called index.rss.builder.

Place this code in that file:

xml.rss('version' => '2.0') do
  xml.channel do 
    xml.title(@page_title)
    xml.link(projects_url)
    xml.description(@page_title)
    @projects.each { |project|
      xml.item do 
        xml.title(project.title)
        xml.link(project_url(project))
        xml.description(project.description)
        xml.pubDate(project.updated_at.rfc822)
      end
    }
  end
end

Now… take the index action in your projects controller and change it from this:

  # GET /projects
  # GET /projects.xml
  def index

    @projects = Project.find :all
 
    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @projects}
    end
 
  end

to this:

  # GET /projects
  # GET /projects.xml
  # get /projects.rss
  def index
  
    @projects = Project.find :all, :order => "update_at desc"
 
    respond_to do |format|
      format.html # index.html.erb
      format.xml  { render :xml => @projects}
      format.rss do 
        @page_title = "Journal entries"
        render :layout=>false
      end
 
    end
 
  end

Start up your server and add some projects. You can then navigate to http://localhost:3000/projects.rss and see the feed.

Now we’re not going to talk about how to cache the feed, but that’s easy enough to figure out.

How do I do this right now, without using Edge rails

The steps are simple.

1. Use this to generate your resource scaffold:

         ruby scriptgenerate scaffold_resource Project title:string description:string
     

2. Name the above mentioned RSS template file projects_rss.rxml
3. Use this for your controller action.

     # GET /projects
     # GET /projects.xml
     # get /projects.rss
     def index
     
       @projects = Project.find :all, :order => "update_at desc"
    
       respond_to do |format|
         format.html # index.html.erb
         format.xml  { render :text => @projects.to_xml}
         format.rss do 
           @page_title = "Projects"
           render :action=>"projects_rss", :layout=>false
         end
    
       end
    
     end