controller.rb

  # exportação de TODOS os dados no formato xml e json
  def export
    @ufs = Uf.find(:all, :order => "uf")
    prawnto :prawn => {:page_layout => :landscape}
    respond_to do |format|
      format.xml  { render :xml => @ufs }
      format.json  { render :json => @ufs }
      format.csv do
          @output_encoding = 'ISO-8859-1'
          @filename = "ufs.csv"
      end
      format.pdf { render :layout => false, :page_layout => :landscape, :pdf => @ufs, :pdf => @ufs }
    end
  end