devise-i18n Documentation

If you need to modify the default translations provided by the gem, you can generate a specific locale file into your project using the devise:i18n:locale generator. This creates a YAML file in config/locales/ that you can edit.

# Example: Generate Italian (it) translation file
rails g devise:i18n:locale it

To use devise-i18n, add it to your Gemfile immediately after the devise gem.

If you have already generated Devise views in your project, you must regenerate them after installing this gem to ensure the internationalized views are applied, then re-apply any custom styling or logic you previously had.

gem 'devise'
gem 'devise-i18n'

To ensure Devise error messages are correctly translated, you must set the locale in your application.

Important: Do not use I18n.with_locale inside an around_action to set the locale per request, as a known Warden bug will prevent some error messages from being translated. Instead, use a before_action in your controller or a custom middleware.

# Option 1: Using a before_action
before_action do
  I18n.locale = :es # Or your dynamic logic
end

# Option 2: Using Middleware
class LocaleMiddleware
  def initialize(app)
    @app = app
  end

  def call(env)
    I18n.locale = :es # Or your dynamic logic
    status, headers, body = @app.call(env)
  end
end

# In config/application.rb
config.middleware.use ::LocaleMiddleware

Use the devise:i18n:views generator to copy the devise-i18n views into your application. This allows you to modify the HTML/ERB files directly.

• If simple_form is present in your Gemfile, the generator will automatically create views using the simple_form builder.
• Note: Generating views means you will not receive automatic updates to these files if devise-i18n updates its default views. To revert to the default gem views, simply delete the generated files from your project.
• To support scoped views (e.g., different views for User and Admin), pass the scope name to the generator.

# Generate default views
rails g devise:i18n:views

# Generate scoped views (e.g., for 'user')
rails g devise:i18n:views user

The devise_i18n_fix_model_name_case helper provides custom logic to adjust the casing of strings (like model names) based on the current locale and the specific I18n key being used.

Specifically, for the errors.messages.not_saved key, the helper will downcase the text unless the current locale is German (de), as German nouns typically require capitalization.

# Usage within a view or helper context
devise_i18n_fix_model_name_case(text, i18n_key: 'errors.messages.not_saved')