data2ruby

Data2ruby

Convert an heterogeneous tree structure in nested ActiveModel::Model objects.

For instance, if you have a JSON object describing a train journey:

{
  "id": 987,
  "connections": [
    {
      "start": "London",
      "finish": "Paris",
      "departure_time": "2015-07-11T09:23:00+01:00",
      "arrival_time": "2015-07-11T12:41:00+02:00",
      "fare": {
        "currency": "GBP",
        "value": 159.0
      }
    },
    {
      "start": "Paris",
      "finish": "Barcelona",
      "departure_time": "2015-07-11T13:56:00+02:00",
      "arrival_time": "2015-07-11T20:17:00+02:00",
      "fare": {
        "currency": "GBP",
        "value": 50.0
      }
    }
  ]
}

You can define a Ruby class describing it as

class TravelOption
  include Data2ruby

  has_one :journey do
    attr_accessor :id
    validates_numericality_of :id, only_integer: true

    has_many :connections do
      attr_accessor :start, :finish, :departure_time, :arrival_time
      validates_presence_of :start, :finish, :departure_time, :arrival_time

      has_one :fare do
        attr_accessor :currency, :value
        validates_presence_of :currency
        validates_numericality_of :value
      end
    end
  end
end

Then instantiate and validate:

travel_option = TravelOption.new(JSON.parse(json_string))

# run ActiveModel validations
travel_option.valid_structure? # => true
travel_option.invalid_items # => []

# navigate the associations
travel_option.journey.id # => 987
travel_option.connections[0].start # => "London"
travel_option.connections[0].fare.currency # => "GBP"

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rmaestroni/data2ruby.

License

The gem is available as open source under the terms of the MIT License.