Speeding up xml view for RSS feed in Rails

Recently, I tried to make a RSS feed faster in my Rails application. I had a Rails application with standard xml.builder view wrote with builder gem.

Example:

xml.instruct! :xml, :version => "1.0"
xml.rss :version => "2.0" do
  xml.channel do
    xml.title "My Company Blog1"
    xml.description "This is a blog by My Company"
    xml.link '/'
    @topics.each do |i|
      xml.item do
        xml.title i.title
        xml.subtitle i.subtitle
        xml.description i.description
        xml.big_text i.big_text
        xml.rubric_id i.rubric_id
        xml.tag_id i.tag_id
        xml.publication_at i.publication_at
        xml.one_more_time i.one_more_time
      end
    end
  end
end

It is absolutely standard xml view for all RSS feeds in Rails. I began an experiment to rewrite it from xml.bulder to xml.erb and it made render faster. For my app, it made it twice as fast as before.

Example:

<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0">
  <channel>
  <title><%= 'My Company Blog1' %></title>
  <description><%= 'This is a blog by My Company' %></description>
  <link><%= '/' %></link>
  <% @topics.each do |i| %>
    <item>
      <title><%= i.title %></title>
      <subtitle><%= i.subtitle %></subtitle>
      <description><%= i.description %></description>
      <big_text><%= i.big_text %></big_text>
      <rubric_id><%= i.rubric_id %></rubric_id>
      <tag_id><%= i.tag_id %></tag_id>
      <publication_at><%= i.publication_at %></publication_at>
      <one_more_time><%= i.one_more_time %></one_more_time>
    </item>
  <% end %>
</channel>
</rss>

Almost the same result we can reach to replace gem builder by ox (the fastest optimized XML parser and generator). But, unfortunately, it has quirky syntax and we don’t have action_view’s template out the box.

In conclusion, there is an easy way to decrease rss response time. I prepared a test application in order to check it out and uploaded it to Github. There is the link to test application with the result — github.