Generating RSS feed in Rails 3

Question

I\'m looking for a best practice/standard pattern for generating feeds in Rails 3. Is http://railscasts.com/episodes/87-generating-rss-feeds still valid?

Answer 1

First of all, nowadays I recommend using an ATOM feed instead of RSS.

The specification of ATOM feed offers more value than the RSS one with internationalization, content types and other things and every modern feed reader supports it.

More info about ATOM vs RSS can be found at:

• the Wikipedia ATOM entry
• PRO Blogger and Free Marketing Zone blog posts about the subject

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On to the coding:

This example assumes:

• a model called NewsItem with the following attributes:
  • title
  • content
  • author_name
• a controller for that model (news_items_controller.rb), to which you'll add the feed action

We'll use a builder template for this and the Ruby on Rails atom_feed helper which is of great use.

1. Add the action to the controller

Go to app/controllers/news_items_controller.rb and add:

def feed
  # this will be the name of the feed displayed on the feed reader
  @title = "FEED title"

  # the news items
  @news_items = NewsItem.order("updated_at desc")

  # this will be our Feed's update timestamp
  @updated = @news_items.first.updated_at unless @news_items.empty?

  respond_to do |format|
    format.atom { render :layout => false }

    # we want the RSS feed to redirect permanently to the ATOM feed
    format.rss { redirect_to feed_path(:format => :atom), :status => :moved_permanently }
  end
end

2. Setup your builder template

Now let's add the template to build the feed.

Go to app/views/news_items/feed.atom.builder and add:

atom_feed :language => 'en-US' do |feed|
  feed.title @title
  feed.updated @updated

  @news_items.each do |item|
    next if item.updated_at.blank?

    feed.entry( item ) do |entry|
      entry.url news_item_url(item)
      entry.title item.title
      entry.content item.content, :type => 'html'

      # the strftime is needed to work with Google Reader.
      entry.updated(item.updated_at.strftime("%Y-%m-%dT%H:%M:%SZ")) 

      entry.author do |author|
        author.name entry.author_name
      end
    end
  end
end

3. Wire it up with a route

Let's make the feeds available at http://domain.com/feed

This will call the action with the ATOM format by default and redirect /feed.rss to /feed.atom.

Go to config/routes.rb and add:

resources :news_items
match '/feed' => 'news_items#feed',
      :as => :feed,
      :defaults => { :format => 'atom' }

4. Add the link to ATOM and RSS feeds on the layout

Finally, all that is left is to add the feed to the layout.

Go to app/views/layouts/application.html.erb and add this your section:

<%= auto_discovery_link_tag :atom, "/feed" %>
<%= auto_discovery_link_tag :rss, "/feed.rss" %>

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There may be a typo or two in that, so let me know if this works for you.