Using Module#prepend to interrogate a str_enum

Question

I have a Rails model, which is using the str_enum gem.

I'm building a generator which reads the models and creates pages for them, and so I'd like to be able to understand what str_enums are attached to a model.

For example

class User < ApplicationRecord
  str_enum :email_frequency, %i[every daily weekly], default: 'every'
end

Ideally, I'd like to be able to query the User model and understand there is a str_enum attached to email_frequency, with values of every, daily & weekly.

Once I can understand there is a str_enum attached to a given field, I can pluralize the field and get the values:

irb(main):004:0> User.email_frequencies
=> ["every", "daily", "weekly"]

The question has also be asked over here and the suggestion is to use Module#prepend. I'm familiar with prepend to conditionally insert methods into a model.

How can I use it for this problem?

EDIT

This is quite simple with validations, for example: get validations from model

Answer 1

If I understand your question correctly is that you wanna get all column that has attached with enum string. If so you can override the gem method like this

# lib/extenstions/str_enum.rb

module Extensions
  module StrEnum
    module ClassMethods
      def str_enum(column, *args)
        self.str_enums << column.to_s.pluralize
        super
      end
    end

    def self.prepended(base)
      class << base
        mattr_accessor :str_enums
        self.str_enums = []
        prepend ClassMethods
      end
    end
  end
end

In the User model

prepend Extensions::StrEnum

Now you can use

User.str_enums

to list all columns has attached with str enum.

Make sure you have add lib directory into load path.