Three Examples of DTOs in Ruby - Method 1: Simple Immutable Object

three_examples_of_dtos_in_ruby_method_1.rb

#
# In this example, all required parameters must be provided during
# construction of the object, or it will fail to be created.
#
# The attributes can be read but not modified after object construction.
#
class BirthdayCard
  attr_reader :from, :to, :messages

  def initialize(from:, to:, messages:)
    @from = from
    @to = to
    @messages = messages
  end
end

# To create this DTO
BirthdayCard.new(from: 'me',
                 to: 'you',
                 messages: ['Wishing you a Happy one!',
                            'You are getting old!'])