How to extend in my app an AR model of my engine so Mobility doesn't complain?

Question

In my plugin I'm inheriting few models from the engine and adding Mobility settings.

# my enginge
module MyEngine
  class Foo < ApplicationRecord
    def self.say_hi
      return "hi"
    end
  end
end

# my plugin
require 'my-engine'
module MyEngine
  class Foo
    include Mobility
    translates :name, type: :string
  end
end

Now if I look for the model in Rails console:

MyEngine::Foo.say_hi
ArgumentError: KeyValue backend can only be used by ActiveRecord or Sequel models

If I comment out Mobility settings everything works:

MyEngine::Foo.say_hi
=> "hi"

How to extend in my app an AR model MyEngine::Foo so Mobility doesn't complain?

I was trying the method explained [here](https://stackoverflow.com/a/45252778/1498118) but I still get the error. — a.barbieri, Aug 29 '17 at 09:14
Hmm I'm not quite sure I understand the question. You can't `translate` an attribute on a class using the (default) `key_value` backend unless the class inherits from either `ActiveRecord::Base` or `Sequel::Model`, otherwise Mobility doesn't know how to setup methods correctly. If you want to do something more flexible, you could use the `Mobility::Attributes` module builder directly, which you can create without knowing the class it will be included in right away. If you can provide more details I can explain how to do this. — Chris Salzberg, Sep 03 '17 at 03:16
Can you not have `class Foo < ApplicationRecord` in your plugin? That should fix the issue. — Chris Salzberg, Sep 03 '17 at 03:19

score 0 · Accepted Answer · answered Aug 29 '17 at 11:09

This answer does help with extending an engine model from a plugin, but doesn't help with mobility.

To use modify MyEngine::Foo to use mobilty you need to create an initializer config/initializers/mobility_models_extension.rb (make sure the file name is alphabetically after mobility.rb file).

:: MyEngine::Foo(:include, Mobility)
:: MyEngine::Foo.send(:translates, :name, type: :string)

See send documentation and initializers documentation

How to extend in my app an AR model of my engine so Mobility doesn't complain?

1 Answers1