xml = <<-eoxml
<?xml version="1.0" ?><Root><Data><?xml version='1.0'?><Item>hey</Item></Data><Data><Item>hey yourself</Item></Data></Root>
eoxml

class Doc < Nokogiri::XML::SAX::Document
  def start_element(name, attributes)
    puts "<#{name}>"
  end

  def end_element(name)
    puts "</#{name}>"
  end

  def characters(string)
    puts string
  end
end

parser = Nokogiri::XML::SAX::Parser.new(Doc.new)
parser.parse(xml) do |ctx|
  ctx.recovery = false
end

<Root>
<Data>
<Item>
hey
</Item>
</Data>
<Data>
<Item>
hey yourself
</Item>
</Data>
</Root>

<Root>
<Data>
hey
hey yourself