Is it possible to use simultaneously 2 I18n backends and use the second one only as a fallback?

Question

Hello,

In my Rails application, I would like to use simultaneously 2 backends, the first one storing translations in a DB, and the second one being the default YML based backend. I woud like that this second backend serves as a fallback backend, ie if a translation is not found in the first, Rails looks up the translation in the second one.

Is it possible to achieve that?

Edit:

My motivation is I would like not to have to store the default Rails translations in the first backend. The first backend I use comes with an admin web interface that display all the translations contained in the backend, I don't want to clutter this interface with those default translations. And I would like not to have to import them in the first backend, neither to have to update them when there are actualized.

Answer 1

The i18n gem does that and is compatible with rails. Actually it is recommended to use it.

From the rdoc of I18n::Backend::Chain:

Backend that chains multiple other backends and checks each of them when a translation needs to be looked up. This is useful when you want to use standard translations with a Simple backend but store custom application translations in a database or other backends.

To use the Chain backend instantiate it and set it to the I18n module. You can add chained backends through the initializer or backends accessor:

# preserves the existing Simple backend set to I18n.backend
I18n.backend = I18n::Backend::Chain.new(I18n::Backend::ActiveRecord.new, I18n.backend)

The implementation assumes that all backends added to the Chain implement a lookup method with the same API as Simple backend does.