json_version_of for Rails ActiveRecord::Base models

json_version_of.rb

  def rename_keys(obj, old_key, new_key)
    renamer = lambda { |i| i.rename_key(old_key, new_key) }

    case obj
      when Array then obj.collect(&renamer)
      when Hash then renamer.call(obj)
      else obj
    end
  end

  def json_version_of(model, options={})
    as = options.delete(:as)
    repr = JSON.parse(model.to_json(options))

    if !as.nil? and options.has_key?(:include)
      rename_keys(repr, options[:include].to_s, as.to_s)
    else
      repr
    end
  end