gistfile1.rb

def print
    @doc = Document.find(params[:id]) 
    respond_to do |format|
      format.html {
        render "final", :layout => "print"
      }
      format.pdf {
        html = render_to_string "final", :layout => "print"
        p [:output,html]
        kit = PDFKit.new(html, :page_size => 'Letter')
        send_data(kit.to_pdf, :filename => @doc.name, :type => "application/pdf")
      }
    end
  end