Nokogiri: Searching for <div> using XPath

nokogiri, regex, ruby, ruby-on-rails, xpath

Solution

Mike Dalessio (one half of the Nokogiri core developers) gave me an answer on `#nokogiri` (irc.freenode.net). Looks like neither Nokogiri CSS nor XPath search do support regex matching. This is his solution on how to search for regular expressions with Nokogiri:

require 'rubygems'
require 'nokogiri'

value = Nokogiri::HTML.parse(<<-HTML_END)
  "<html>
    <body>
      <p id='para-1'>A</p>
      <p id='para-22'>B</p>
      <h1>Bla</h1>
      <p id='para-3'>C</p>
      <p id='para-4'>D</p>
      <div class="foo" id="eq-1_bl-1">
        <p id='para-5'>3</p>
      </div>
      <div class="bar" id="eq-1_bl-1">
        <p id='para-5'>3</p>
      </div>
    </body>
  </html>"
HTML_END

# my_block is given
my_bl = "1"
# my_eq corresponds to this regex
my_eq = "[0-9]+"
# full regex to search for in node ids
full_regex = %r(eq-#{my_eq}_bl-#{my_bl})

filter_by_id = Class.new do
  attr_accessor :matches

  def initialize(regex)
    @regex = regex
    @matches = []
  end

  def filter(node_set)
    @matches += node_set.find_all { |x| x['id'] =~ @regex }
  end
end.new(full_regex)

value.css("div.foo:filter()", filter_by_id)
filter_by_id.matches.each do |node|
  puts node
end

Problem

I use Nokogiri (Rubygem) css search to look for certain `<div>` inside my html. It looks like Nokogiri's css search doesn't like regex. I would like to switch to Nokogiri's xpath search as this seems to support regex in search strings. How do I implement the (pseudo) css search mentioned below in an xpath search? ``` require 'rubygems' require 'nokogiri' value = Nokogiri::HTML.parse(<<-HTML_END) "<html> <body> <p id='para-1'>A</p> <p id='para-22'>B</p> <h1>Bla</h1> <p id='para-3'>C</p> <p id='para-4'>D</p> <div class="foo" id="eq-1_bl-1"> <p id='para-5'>3</p> </div> </body> </html>" HTML_END # my_block is given my_bl = "1" # my_eq corresponds to this regex my_eq = "\/[0-9]+\/" # FIXME The following line should be changed to an xpath search. if my_div = value.css("div#eq-#{my_eq}_bl-#{my_bl}.foo").first # doing some stuff with the <p> inside the div end ```

Original source