Custom to_xml for ActiveRecord classes

In an attempt to product client definable API returns, Dean Radcliffe, Jake Scruggs and I decided that using the local files would be a good idea. I mentioned this in a previous post. It is a great idea, and the execution is pretty sweet as well.

I am currently fighting with a way to do the sub level arrays such as

Document has many Document tags

So a layout like
<doc>
<tags>
   <tag>Tag 1</tag>
   <tag>Tag 2 </tag>
<t/ags>
</doc>

where Tags are objects themselves

I got a solution working but it is course and not using Builder XML.

It uses <<--DOCXML DOCXML tags and internally hand hacked xml arguments.

Nasty...

  def to_xmls
    xml_class_fetch = self.class.to_s.downcase
    buff = <<-EOF
    <#{xml_class_fetch}>
    #{ClientConfig.get("xml_export.#{xml_class_fetch}").map do | xml_field_name, method_call |
    case method_call
    when Symbol
      val = self.send(method_call)
    when String
      val = self.instance_eval(method_call)
    end

    if val.is_a?(Array)
      val = val.map do |element|
        if element.respond_to?(:name)
          element_call = element.name
        elsif element.respond_to?(:identifier)
          element_call = element.identifier
        end
        "<#{xml_field_name.singularize}>#{element_call}</#{xml_field_name.singularize}>"
      end
    end

    "<#{xml_field_name}>#{val}</#{xml_field_name}>"
    end.join("\n")}
    </#{xml_class_fetch}>
    EOF
  end


where the feed looks like

  xml_export:
    document:
      # TODO - may add XML element names etc ...
      - ["other-id", :other_id]
      - ['created-at', :created_at]
      - ['tags', "tags.to_a"]



As one can imagine, I am not happy with this solution at all.

If any one has any better suggestions to return valid XML with nested elements that are part of the model's has_and_belongs_to_many as well as other types of associations, please feel free to shoot me a tweet or comment.