Generating XML for ActiveRecord associations using batched find

I have a controller that returns XML for a has_many association in the most straight-forward but inefficient way possible:

@atoms = @molecule.atoms.find(:all, :include => :neutrons)

render :xml => @atoms.to_xml(:root => 'atoms')

This fetches and instantiates all objects at once. To make this more memory efficient I开发者_如何学C'd like to use ActiveRecord's batched find. At first glance, this seems to be the only way to do it:

xml = '<atoms>'
@molecule.atoms.find_each(:include => :neutrons) do |atom|
  xml << atom.to_xml
end
xml << '</atoms>'

render :xml => xml

This is definitely more memory efficient but is decidedly less elegant. It duplicates some of the existing functionality of Array#to_xml.

Is there a way to harness the power of find_each without building XML by hand?

My usual approach to generating XML is to use the XML Builder template.

#in the controller
respond_to do |format|
  format.html # index.html.erb
  format.xml # index.xml.builder
end

#in index.xml.builder
xml.atoms {
  @molecule.atoms.find_each(:include => :neutrons) do |atom|
     #etc
  end
}