Where exactly do I put autoload path for custom validator in config/application.rb

Question

Every time I call validates_with NumberValidator. I get an uninitialized constant error. I have created a directory called validators under the "app" directory. This is what I have so far.

This is my model

class Worker < ActiveRecord::Base
    include ActiveModel::Validations
validates_with NumberValidator

end

This is my validator file

class NumberValidator < ActiveModel::Validator
    def validate(record, attribute, value)
        puts record
        puts attribute
        puts value
    end
end

require File.expand_path('../boot', __FILE__)

require "rails"
# Pick the frameworks you want:
require "active_model/railtie"
require "active_job/railtie"
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "action_view/railtie"
require "sprockets/railtie"
# require "rails/test_unit/railtie"

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module ApplicationName
  class Application < Rails::Application
    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.

    # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
    # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
    # config.time_zone = 'Central Time (US & Canada)'

    # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
    # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
    # config.i18n.default_locale = :de

    # Do not swallow errors in after_commit/after_rollback callbacks.
    config.active_record.raise_in_transactional_callbacks = true

    config.autoload_paths += %W["#{config.root}/app/validators/"]
  end
end

I have restarted my server and I'm just not sure what I am doing wrong

Answer 1

Rails will automatically load anything under app/ assuming you follow the expected structure. The way Rails does this is with Constant Autoloading, which maps a constant, such as MyValidator to a file name, such as my_validator.rb under a directory in the autoload paths.

In order for Rails to load your NumberValidator, you should name the file number_validator.rb and put it in a folder in the autoload path, such as app/validators/number_validator.rb. You will need to restart the server if you have added a directory under app because these are initialized at boot time (be sure to run spring stop if you are using spring so it restarts too!).

Notes:

1. You do not need to add anything under app to your app config, so you can remove the config.autoload_paths line.
2. ActiveRecord::Base already includes ActiveModel::Validations, so you can also remove that include from your Worker class.

For more information on how this process works, check out the Autoloading and Reloading Constants page in the Rails Guides.