xml builder by Nokogiri

action.xml.nokogiri

xml.feed(:xmlns => "http://www.w3.org/2005/Atom") { |feed|
  feed.title("#{user.name}'s Private Notification Feed")
  feed.link(:href => "http://#{account.subdomain}.domain.com/feeds/#{user.email_alias}.xml", :rel => "self")
  feed.link(:href => "http://#{account.subdomain}.domain.com")
}

nokogiri_builder.rb

require 'nokogiri'
require 'action_view'

class NokogiriBuilder < ActionView::TemplateHandler
  include ActionView::TemplateHandlers::Compilable

  def compile template
    "_set_controller_content_type(Mime::XML);" +
      "xml = ::Nokogiri::XML::Builder.new { |xml|" +
      template.source +
      "}.to_xml; self.output_buffer = xml;"
  end
end

ActionView::Template.register_template_handler :nokogiri, NokogiriBuilder

xxx_controller.rb

def feed
  ...
  respond_to do |format|
    format.xml
  end
end