Using ActiveModel translation with PORO

Coding the API project that I talked about in this post, I wanted to translate the Bmi attributes to Portuguese in the validation error message.

So I searched how to use i18n to translate the attributes of a PORO.

I discovered I could use ActiveModel::Translation because it integrates the object and Rails internationalization (i18n) framework.

To do so, I implemented this line in my code:

class Bmi
  extend ActiveModel::Translation

Then, I created the yml file bmi.yml with the following configuration:

pt-BR:
  activemodel:
      attributes:
        imc:
          height: Altura
          weight: Peso

This configuration is very similar to the translation using ActiveRecord, replacing the name activerecord with activemodel.

So, for example, if you create an instance object with the following parameters:

bmi = Bmi.new(height: 0, weight: 76)

Validating the object the message error will be:

bmi.valid? #=> false

bmi.errors.full_messages #=> ["Altura deve ser maior que 0"]

With the BMI attribute translated.