Blog Tutorial generating RSS feed

Generating RSS Feed for Posts

Finally, before the application is deployed, let's set up RSS and Atom feeds for our new blog so people can subscribe to our posts. For the feeds, we're going to head back to the posts controller and make a few changes by appending a provides option to our index block. This command below instructs the route that it should respond to HTML, RSS and Atom formats.

# app/controllers/posts.rb
SampleBlogUpdated::App.controllers :posts do
# ...
  get :index, :provides => [:html, :rss, :atom] do
    @posts = Post.order('created_at DESC').all
    render 'posts/index'
  end
# ...
end

Note that this route also instructs the rendering engine to avoid rendering the layout when using RSS or atom formats.

Back in the index.haml file, we'll use the auto_discovery_link_tag helpers to generate the RSS feed using builder.

-# app/views/posts/index.haml
- @title = "Welcome"

- content_for :include do
  = feed_tag(:rss, url(:posts, :index, :format => :rss), :title => "RSS")
  = feed_tag(:atom, url(:posts, :index, :format => :atom), :title => "ATOM")

#posts= partial 'posts/post', :collection => @posts

Next, let us add the templates for atom using builder templates:

# app/views/posts/index.atom.builder

xml.instruct!
xml.feed "xmlns" => "http://www.w3.org/2005/Atom" do
  xml.title   "Padrino Sample Blog"
  xml.link    "rel" => "self", "href" => url_for(:posts, :index)
  xml.id      url_for(:posts, :index)
  xml.updated @posts.first.created_at.strftime "%Y-%m-%dT%H:%M:%SZ" if @posts.any?
  xml.author  { xml.name "Padrino Team" }

  @posts.each do |post|
    xml.entry do
      xml.title   post.title
      xml.link    "rel" => "alternate", "href" => url_for(:posts, :show, :id => post)
      xml.id      url_for(:posts, :show, :id => post)
      xml.updated post.created_at.strftime "%Y-%m-%dT%H:%M:%SZ"
      xml.author  {}
    end
  end
end

and also the template for rss using builder:

# app/views/posts/index.rss.builder

xml.instruct!
xml.rss "version" => "2.0", "xmlns:dc" => "http://dublincore.org/documents/dc-xml-guidelines/" do
  xml.channel do
    xml.title "Padrino Blog"
    xml.description "The fantastic padrino sample blog"
    xml.link url_for(:posts, :index)

    for post in @posts
      xml.item do
        xml.title post.title
        xml.description post.body
        xml.pubDate post.created_at
        xml.link url_for(:posts, :show, :id => post.id)
      end
    end
  end
end

Please note, that you have to add builder in your Gemfile and run bundle. Let's check out our changes. View the available feeds at http://localhost:3000/posts.atom or http://localhost:3000/posts.rss. You now have rss and atom feeds available for your blog!