Some thoughts on Virtus use in our project.

_virtus_vs_plain_method.markdown

The more Virtus code I wrote, the more awkward I feel it is. It's not because Virtus is inherently bad, I just don't think it fits our case.

1. So many attributes need to be marked reader: :private. It's not ruby's way. Ruby has its own private keyword.

2. NilToDefault is bad. How do I decide whether a model need to include it? Or we simply include it everywhere?

3. The difference between writer_class and default is subtle. Why does the implementer add a new writer_class here? Why does he use default value there? We're using different ways to do the same thing (compute values) here.

4. writer_class is awkward. Why do I need to create a class just for its coerce method? I feel like writing Java.

5. default method is the most awkward. We turn every computed attribute from a single method to two method (attribute and the default method) by using Virtus. There're dozens of attributes like beds below in ListingPresenter.

6. The type annotation is useless.

plain_base.rb

module Listing
  class Base

    def initialize(attributes)
      @attributes = attributes
    end

    def addressline1
      @attributes['addressline1']
    end

    def agappointmentactive
      @attributes['agappointmentactive'] == '1' ? true : false
    end

    def beds
      format_range(@attributes['listingbedlow'], @attributes['listingbedhigh'])
    end

    def listingseopath
      seo_path =~ %r{^/} ? seo_path : "/#{seo_path}"
    end

  end
end

virtus_base.rb

module Listing
  module Base
    include Virtus

    attribute :addressline1,               String
    attribute :agappointmentactive,        Virtus::Attribute::Boolean

    attribute :beds,                       String, default: :default_beds
    attribute :listingbedhigh,             Integer, reader: :private
    attribute :listingbedlow,              Integer, reader: :private
    def default_beds
      format_range(listingbedlow, listingbedhigh)
    end

    class SeoPathWriter < Virtus::Attribute::Writer::Coercible
      # @param seo_path [String] Relative path from Endeca
      # @return [String] Absolute path
      def coerce(seo_path)
        seo_path =~ %r{^/} ? seo_path : "/#{seo_path}"
      end
    end
    attribute :listingseopath,             String, writer_class: SeoPathWriter

  end
end