Question

I’m using xml-mapping within my ruby on rails app.

I need to load xml files and parse those to objects using xml-mapping

xml example is here

<?xml version="1.0" encoding="UTF-8"?>
<elements type="array">
  <element></element>
  <element></element>
  ...
</elements>

and here is the ruby code

require 'xml/mapping'

class Macro; end

class Elements
  include XML::Mapping

  array_node :elements, "elements","element" :class => Element
end

class Element
  include XML::Mapping

  text_node :name, "name"
  text_node :description, "description"      
end

The problem is when I use Elements.load_from_file("my.xml") it doesn’t load array, but if I add root node to xml it works.

this xml works

<?xml version="1.0" encoding="UTF-8"?>
<mynode>
<elements type="array">
  <element></element>
  <element></element>
  ...
</elements>
<mynode>

Does anybody know how to fix this?

Answer 1

(I’m the xml-mapping author)

The XPath expressions are always relative to the mapped class’s base node in the XML tree, which is the “elements” element for the “Elements” class. So you mustn’t include that name in XPath expressions in Elements’s nodes. Just leave it out and the code should work:

class Elements
  include XML::Mapping

  array_node :elements, "element", :class => Element
end