Merging a document into another

[cv]

Greetings,

I'm new to Ruby and Nokogiri, so please forgive the cluelessness. 

I'm trying to put together some code that "merges" two documents. The idea is basically to add any nodes that are not present, and if a matching node exists, but it differs, correct it.

I'm using traverse, replace and add_child, and not exactly getting the expected results. Before I keep trying to make it work, I'd like to know if I'm totally off. Here's the code:

require 'nokogiri'

require 'pp'

class Nokogiri::XML::Node

  # Determine if two nodes are equal

  # (borrowed from nokogiri-diff)

  def is_equal(node)

    if (self.class == node.class)

      case node

      when Nokogiri::XML::Attr

        (self.name == node.name && self.value == node.value)

      when Nokogiri::XML::Element, Nokogiri::XML::DTD

        self.name == node.name

      when Nokogiri::XML::Text, Nokogiri::XML::Comment

        self.text == node.text

      when Nokogiri::XML::ProcessingInstruction

        (self.name == node.name && self.content = self.content)

      else

        false

      end

    else

      false

    end

  end

end

class Nokogiri::XML::Document

  # Merge XML document into another

  # 

  # Paramters:

  # patch - XML (patch) document

  # 

  # Returns:

  # String with merged XML

  #

  def merge(patch) 

    

    patch.root.traverse do |node|

      path = node.path

      if ( mynode = self.at(path) )

        puts "Found node at #{path} containing: #{node}"

        if ( !node.is_equal(mynode) )

          puts "Node #{pp node} is not equal to #{mynode}"

          mynode.replace(node)

        else

          puts "Node #{pp node} is equal to #{mynode}"

        end

      else

        puts "Node not found at #{path}"

        ppath = node.parent.path

        puts "Parent's path is #{ppath}"

        if ( mypar = self.at(ppath) )

          mypar.add_child(node)

        else

          puts "Parent not found at #{ppath}"

        end

      end

    end

    return self.to_xml        

  end

end

dir = '/home/test/'

f1 = dir + 'config.xml'

f2 = dir + 'patch.xml'

xml1 = Nokogiri::XML(File.open(f1))

xml2 = Nokogiri::XML(File.open(f2))

puts xml1.merge(xml2)

----

Any pointers would be very much appreciated.

cv

[cv]

Or is there a much simpler way to do this with Nokogiri Builder?