gistfile1.rb

class Feed
  def page
    @page ||= get_url
  end

  def posts
    @posts ||= do
      post_nodes.map do |post_node|
        build_post(post_node)
      end
    end
  end
  def post_nodes
    page.get_xpath(event_node_xpath)
  end

end
class MillEvents < Feed
  def event_node_xpath
    "//item"
  end
  def build_post(post_node)
    MillPost.new(post_node)
  end
end

class Post
  attr :node
  def initialize(node)
    @node = node
  end
  def description
    node.get_xpath(description_xpath)
  end
  def title
    node.get_xpath(title_xpath)
  end
  def attributes
    attributes = {}
    %w(identifier description title).each do |attr|
      attributes[attr.to_sym] = self.send(attr)
    end
    attributes
  end
end
class MillPost < Post
  def title_xpath
    "./title"
  end
  def identifier
    # compute an id for node
  end
end

%w(mill).each do |venue|
  get_const("#{venue.camelize}Events").posts.each do |post|
    if event = Event.find(:one, :conditions => {:venue => venue, :identifier => post.identifier})
      # update event
    else
      Event.create(post.attributes)
    end
  end

end