I18n::Backend::ActiveRecord

This repository contains the I18n ActiveRecord backend and support code that has been extracted from the I18n gem: http://github.com/svenfuchs/i18n. It is fully compatible with Rails 4 and higher.

For Bundler put the following in your Gemfile:

gem 'i18n-active_record', require: 'i18n/active_record'

After updating your bundle, run the installer

$ rails g i18n:active_record:install

It creates a migration:

class CreateTranslations < ActiveRecord::Migration
  def change
    create_table :translations do |t|
      t.string :locale
      t.string :key
      t.text :value
      t.text :interpolations
      t.boolean :is_proc, default: false

      t.timestamps
    end
  end
end

To specify table name use:

$ rails g i18n:active_record:install MyTranslation

With the translation model you will be able to manage your translation, and add new translations or languages through it.

By default the installer creates a new file in config/initializers named i18n_active_record.rb with the following content.

require 'i18n/backend/active_record'

Translation = I18n::Backend::ActiveRecord::Translation

if Translation.table_exists?
  I18n.backend = I18n::Backend::ActiveRecord.new

  I18n::Backend::ActiveRecord.send(:include, I18n::Backend::Memoize)
  I18n::Backend::Simple.send(:include, I18n::Backend::Memoize)
  I18n::Backend::Simple.send(:include, I18n::Backend::Pluralization)

  I18n.backend = I18n::Backend::Chain.new(I18n::Backend::Simple.new, I18n.backend)
end

To perform a simpler installation use:

$ rails g i18n:active_record:install --simple

It generates:

require 'i18n/backend/active_record'
I18n.backend = I18n::Backend::ActiveRecord.new

You may also configure whether the ActiveRecord backend should use destroy or delete when cleaning up internally.

I18n::Backend::ActiveRecord.configure do |config|
  config.cleanup_with_destroy = true # defaults to false
end

To configure the ActiveRecord backend to cache translations(might be useful in production) use:

I18n::Backend::ActiveRecord.configure do |config|
  config.cache_translations = true # defaults to false
end

The ActiveRecord backend can be configured to use a scope to isolate sets of translations. That way, two applications using the backend with the same database table can use translation data independently of one another. If configured with a scope, all data used will be limited to records with that particular scope identifier:

I18n::Backend::ActiveRecord.configure do |config|
  config.scope = 'app1' # defaults to nil, disabling scope
end

You can now use I18n.t('Your String') to lookup translations in the database.

By default, the gem relies on the built-in translation model.
However, to extend the default functionality, the translation model can be customized:

class MyTranslation < I18n::Backend::ActiveRecord::Translation
  def value=(val)
    super("custom #{val}")
  end
end

I18n::Backend::ActiveRecord.configure do |config|
  config.translation_model = MyTranslation
end

To make the I18n::Backend::ActiveRecord::Missing module working correctly pluralization rules should be configured properly. The i18n.plural.keys translation key should be present in any of the backends. See https://github.com/svenfuchs/i18n-active_record/blob/master/lib/i18n/backend/active_record/missing.rb for more information.

en:
  i18n:
    plural:
      keys:
        - :zero
        - :one
        - :other

The interpolations field in the translations table is used by I18n::Backend::ActiveRecord::Missing to store the interpolations seen the first time this Translation was requested. This will help translators understand what interpolations to expect, and thus to include when providing the translations.

The interpolations field is otherwise unused since the "value" in Translation#value is actually used for interpolation during actual translations.

• http://collectiveidea.com/blog/archives/2016/05/31/beyond-yml-files-dynamic-translations/ (use before_action for Rails 5.1+)

The test suite can be run with:

bundle exec rake

By default it runs the tests for SQLite database, to specify a database the DB env variable can be used:

DB=postgres bundle exec rake
DB=mysql bundle exec rake

To run tests for a specific rails version see Appraisal:

bundle exec appraisal rails-4 rake test

• Sven Fuchs
• Tim Masliuchenko