Convert relative links to absolute in HTML

gistfile1.rb

#!/usr/bin/env ruby
# encoding: utf-8

# This works pretty well, but can't yet go up dir tree
# Also doesn't work on JS generated hrefs/srcs
# I was surprised there wasn't a ready-made solution online (that I could quickly find)

require 'open-uri'
require 'nokogiri'
require 'active_support/core_ext'

def convert_to_abs(base_uri,rel_uri)
  # Note: can't follow up (i.e. "..")
  base_uri = URI.parse(base_uri)
  rel_uri  = URI.parse(rel_uri)
  if (rel_uri.class == URI::Generic) and not rel_uri.path.blank?
    URI.join(base_uri,rel_uri).to_s
  else
    rel_uri.to_s
  end
end

url_lookup = "http://library.tcu.edu/govweb/"
doc = Nokogiri::HTML(open(url_lookup))

doc.xpath("//@href | //@src").each do |x|
  x.value = convert_to_abs(url_lookup,x.value)
end

puts doc.to_html