using to_xml and to_json hiding certain attributes

serializable_hash_example.rb

# require 'rubygems'
require 'active_model'

class LegacyTable
  
  include ActiveModel::Serialization
  include ActiveModel::Serializers::JSON
  include ActiveModel::Serializers::Xml
  
  attr_accessor :nice_attribute, 
                :crappy_old_attribute, 
                :hide_from_xml, 
                :hide_from_json
  
  def attributes
    {
      'nice_attribute'       => nice_attribute,
      'crappy_old_attribute' => crappy_old_attribute,
      'hide_from_xml'        => hide_from_xml,
      'hide_from_json'       => hide_from_json
    }
  end
  
  def method_that_is_not_in_attributes
    'method that is not in attributes/db but we want to include'
  end

  # the clean way to do this would be to override serializable_hash
  # but to_xml ignores it so this is best way i could see how to do it
  def default_serialization_options
     {
      :except  => ['crappy_old_attribute'],
      :methods => ['method_that_is_not_in_attributes']
    }
  end
  
  # you can also hide or add certain methods/attributes for xml or json specifically
  def as_json(options = {})
    options ||= {}
    options = default_serialization_options.merge(options)
    options[:except] << 'hide_from_json'
    super(options)
  end
  
  def to_xml(options = {})
    options ||= {}
    options = default_serialization_options.merge(options)
    options[:except] << 'hide_from_xml'

    super(options)
  end
end

lt = LegacyTable.new

puts "serializable_hash"
puts "==="
puts lt.serializable_hash

puts "as json"
puts "==="
puts lt.as_json

puts "to json"
puts "==="
puts lt.to_json

puts "to xml"
puts "==="
puts lt.to_xml