标记要在模块中使用的特定 Rails 模型的最佳方法

Question

I am trying to write a lib plugin/extension to perform an action where I need to know which Models have been marked for use with this plugin.

Currently, I am marking the models in the fashion of acts_as_something method which is added to each Model intended to be used with the plugin.

The main file of the plugin looks like this

# lib/foo.rb
module Foo
  class << self
    attr_accessor :models
  end
  self.models = []

  module Model
    def acts_as_foo
      Foo.models << self
    end
end

ActiveSupport.on_load(:active_record) do
  extend Foo::Model
end

The intended use is to then call in a controller Foo.perform , which needs to know the marked models in order to carry out the intended action, the idea being getting the list of models from Foo.models .

It works as intended if when config.eager_load is set to true in development.rb , otherwise the files of the models have not been used/loaded yet and therefore Foo.models is an empty Array.

My goal is to be able to add more models to Foo without having to change Foo's code like this.

#app/models/bar.rb
class Bar < ApplicationRecord
  acts_as_foo
end

Any ideas on the best way to implement this?

Answer 1

I had a similar problem before in my gem .

I ended up loading ONLY model files (which is the minimum of my requirement same as yours because the DSL code is there like your acts_as_foo ), and not immediately eager loading all Rails-related files using Rails.application.eager_load! .

# lib/foo.rb
module Foo
  class << self
    attr_accessor :models
  end

  self.models = []

  class Engine < Rails::Engine
    initializer 'foo.eager_load_models' do |app|
      unless app.config.eager_load
        models_load_path = File.join(Rails.root, 'app', 'models')

        # copied from https://apidock.com/rails/Rails/Engine/eager_load%21/class
        matcher = /\A#{Regexp.escape(models_load_path.to_s)}\/(.*)\.rb\Z/
        Dir.glob("#{models_load_path}/**/*.rb").sort.each do |file|
          app.require_dependency file.sub(matcher, '\1')
        end
      end
    end
  end

  module Model
    def acts_as_foo
      Foo.models << self
    end
  end
end

ActiveSupport.on_load(:active_record) do
  extend Foo::Model
end