Dan Chak’s Blog

My new company is building an product that is both a web site and an iPhone app. Both are backed by the same web-service, which returns either xml or plists based on who’s asking.

For the web site, we return xml created using ROXML. The iPhone app does best when we send back plists, because they can be read easily with Objective C 2.0’s built-in libraries.

The following bit of code, injected into the base class of our “Service Objects” (as per Enterprise Rails), allows classes marked as with ROXML attributes to be serialized either as xml or as plists. to_xml returns the ROXML version as usual, but now xml_attributes_as_hash.to_plist returns a plist. xml_attributes_to_hash recursively turns all XML attributes into hashes (whether the attribute is another ServiceObject, an array, a hash, or a discrete value).

Of course, you need to have installed the ruby plist gem in order for “to_plist” to have any meaning.

module NewsService
  class ServiceObject
    include ROXML

    def as_hash(val)
      case val.class.to_s
      when "Array"
        return val.collect{|e| as_hash(e)}
      when "Hash"
        h = Hash.new
        val.each{|k,v| h[k] = as_hash(v)}
        return h
      else
        val.kind_of?(ServiceObject) ? as_hash(val.xml_attributes_as_hash) : val
      end
    end

    def xml_attributes_as_hash
      h = Hash.new
      attrs = self.class.roxml_attrs.collect{|a| a.accessor}

      for tag in attrs do
        val = self.send(tag)
        h[tag] = as_hash(val) if val
      end
      return h
    end
  end
end