Response.rb. Updated to include error subclass.

response.rb

class Response
  attr_accessor :data

  delegate :[], :map, :select, :each, :first, :inject, to: :data

  def initialize(data = nil)
    self.data = data
  end

  def value
    data
  end

  def result
    data
  end

  def success?
    true
  end

  def error?
    false
  end

  def transform(transformed = nil)
    self.data = block_given? ? yield(data) : transformed
    self
  end
end

class ResponseError < Response

  attr_reader :message, :error, :status

  def initialize(error, options = {})
    if error.is_a?(Exception)
      self.error = error
    elsif error.is_a?(String)
      self.error = RuntimeError.new(error)
    else
      raise RuntimeError, "Unknown error specified #{error.inspect}"
    end

    self.message = options[:message] || self.error.message
    self.status = options[:status]
  end

  def success?
    false
  end

  def error?
    true
  end
end