07 - substituting xml entities.rb

O Reilly Ruby Cookbook source code

require 'rexml/document'

str = %{<?xml version="1.0"?>
<!DOCTYPE doc [
 <!ENTITY product 'Stargaze'>
 <!ENTITY version '2.3'>
]>
<doc>
 &product; v&version; is the most advanced astronomy product on the market.
</doc>}
doc = REXML::Document.new str

doc.root.children[0].value
# => "\n Stargaze v2.3 is the most advanced astronomy product on the market.\n"
doc.root.text
# => "\n Stargaze v2.3 is the most advanced astronomy product on the market.\n"

doc.root.children[0].to_s
# => "\n &product; v&version; is the most advanced astronomy product on the market.\n"
doc.root.write
# <doc>
#  &product; v&version; is the most advanced astronomy program on the market.
# </doc>
#---
require 'delegate'
require 'rexml/text'
class EntitySubstituter < DelegateClass(IO)
  def initialize(io, document, filter=nil)
    @document = document
    @filter = filter
    super(io)
  end
  
  def <<(s)
    super(REXML::Text::unnormalize(s, @document.doctype, @filter))
  end
end

output = EntitySubstituter.new($stdout, doc)
doc.write(output)
# <?xml version='1.0'?><!DOCTYPE doc [
# <!ENTITY product "Stargaze">
# <!ENTITY version "2.3">
# ]>
# <doc>
#  Stargaze v2.3 is the most advanced astronomy product on the market.
# </doc>
#---
text_node = doc.root.children[0]
text_node.value = "&product; v&version; has a catalogue of 2.3 " +
                  "million celestial objects."

doc.write
# <?xml version='1.0'?><!DOCTYPE doc [
# <!ENTITY product "Stargaze">
# <!ENTITY version "2.3">
# ]>
# <doc>&product; v&version; has a catalogue of &version; million celestial objects.</doc>
#---
text_node.raw = true
doc.write
# <?xml version='1.0'?><!DOCTYPE doc [
# <!ENTITY product "Stargaze">
# <!ENTITY version "2.3">
# ]>
# <doc>&product; v&version; has a catalogue of 2.3 million celestial objects.</doc>

text_node.value
# => "Stargaze v2.3 has a catalogue of 2.3 million celestial objects."
text_node.to_s
# => "&product; v&version; has a catalogue of 2.3 million celestial objects."
#---
str = %{
  <!DOCTYPE doc [ <!ENTITY year '2006'> ]>
  <doc>&copy; &year; Komodo Dragon &amp; Bob Productions</doc>
}

doc = REXML::Document.new str
text_node = doc.root.children[0]

text_node.value
# => "&copy; 2006 Komodo Dragon & Bob Productions"
text_node.to_s
# => "&copy; &year; Komodo Dragon &amp; Bob Productions"
#---