Ox vs Nokogiri: DOM and SAX parsing comparison

benchmark

# I'm no benchmark guru. Just did a bunch of:
$ time ruby <filename>

# Note: This is just an 80mb XML file with 38,000 nodes.

ox_dom.rb        4.56s  user 0.78s system 93% cpu 5.714  total (550mb)
ox_dom.rb        4.58s  user 0.79s system 87% cpu 6.126  total (550mb)
ox_dom.rb        4.60s  user 0.80s system 87% cpu 6.140  total (550mb)
nokigiri_dom.rb  11.75s user 1.02s system 94% cpu 13.518 total (895mb)
nokigiri_dom.rb  11.36s user 1.02s system 93% cpu 13.211 total (895mb)
nokigiri_dom.rb  11.57s user 1.03s system 94% cpu 13.326 total (900mb)
ox_sax.rb        4.37s  user 0.41s system 81% cpu 5.848  total (12.3mb)
ox_sax.rb        4.47s  user 0.43s system 91% cpu 5.339  total (11.8mb)
ox_sax.rb        4.29s  user 0.41s system 82% cpu 5.724  total (12.0mb)
nokogiri_sax.rb  23.01s user 0.52s system 98% cpu 23.782 total (11.9mb)
nokogiri_sax.rb  23.40s user 0.55s system 98% cpu 24.319 total (11.8mb)
nokogiri_sax.rb  23.18s user 0.54s system 98% cpu 24.022 total (11.7mb)

nokogiri_dom_parsing.rb

require "nokogiri"

doc = Nokogiri::XML(open("user.xml"))

doc.search("//row").each do |post|
  @user = {}
  @user[:userid] = post.at("userid").text.to_i
  @user[:username] = post.at("username").text
  @user[:email] = post.at("email").text
  puts @user[:userid], @user[:username], @user[:email]
end

nokogiri_sax_parsing.rb

require "nokogiri"
class UsersDocument < Nokogiri::XML::SAX::Document
  USER_ATTR = %w[userid username email]

  def start_element(name, attrs=[])
    @user = {} if name == "row"
    @current_node = name
  end

  def characters(string)
    return unless USER_ATTR.include?(@current_node)
    @user[@current_node] = string unless string.strip.empty?
  end

  def end_element(name)
    return unless name == "row"
    puts @user["userid"], @user["username"], @user["email"]
  end
end

parser = Nokogiri::XML::SAX::Parser.new(UsersDocument.new)
parser.parse_file("user.xml")

ox_dom_parsing.rb

# Check out Ox's tests to see how to iterate through it: https://github.com/ohler55/ox/blob/master/test/parse_cmp.rb

require "ox"
require "open-uri"

USER_ATTR = %w[userid username email]

def first_text(node)
  node.nodes.each do |n|
    return n if n.is_a?(String)
  end
  nil
end

def get_value(node)
  case node.name
  when "userid" 
    first_text(node).to_i
  when "username", "email"
    first_text(node)
  end
end

doc = Ox.parse(open("user.xml").read)
plist = doc.root
rows = plist.nodes.first.nodes

rows.each do |row|
  @user = {}
  row.nodes.each do |node|
    if USER_ATTR.include?(node.name)
      @user[node.name] = get_value(node)
    end
  end
  puts @user["userid"], @user["username"], @user["email"]
end

ox_sax_parsing.rb

require "ox"
require "open-uri"

class Handler < Ox::Sax
  USER_ATTR = [:userid, :username, :email]
  ATTR_MAP = { userid: :as_i, username: :as_s, email: :as_s}

  def start_element(name)
    @user = {} if name == :row
    @current_node = name
  end

  def value(value)
    return unless USER_ATTR.include?(@current_node)
    @user[@current_node] = value.send(ATTR_MAP[@current_node])
  end

  def end_element(name)
    return unless name == :row
    puts @user[:userid], @user[:username], @user[:email]
  end
end

handler = Handler.new
File.open("user.xml") do |f|
  Ox.sax_parse(handler, f)
end

user.xml

<!-- 80mb file, 38,000 row nodes -->
<?xml version="1.0"?>
<data>
  <users>
    <row>
      <userid>1</userid>
      <username>danneu</username>
      <email>danrodneu@gmail.com</email>
      <dozens>etc.</dozens>
      <more>etc.</more>
      <nodes>etc.</nodes>
    </row>
    <row>
      <userid>2</userid>
      ...
    </row>
    ...
  </users>
</data>