Prepare for API v1 (PR #570)

app/controllers/concerns/locale.rb

@@ -0,0 +1,51 @@
+module Concerns::Locale
+  extend ActiveSupport::Concern
+
+  included do
+    before_filter :set_locale
+  end
+
+  def explicitly_requested_language
+    params[:locale]
+  end
+
+  def user_settings_language
+    current_user&.locale
+  end
+
+  def session_language
+    session[:locale]
+  end
+
+  def browser_language
+    request.env['HTTP_ACCEPT_LANGUAGE'] ? request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first : nil
+  end
+
+  def default_language
+    FoodsoftConfig[:default_locale] || ::I18n.default_locale
+  end
+
+  private
+
+  def select_language_according_to_priority
+    language = explicitly_requested_language || session_language || user_settings_language
+    language ||= browser_language unless FoodsoftConfig[:ignore_browser_locale]
+    language.presence&.to_sym unless language.blank?
+  end
+
+  def available_locales
+    ::I18n.available_locales
+  end
+
+  def set_locale
+    if available_locales.include?(select_language_according_to_priority)
+      ::I18n.locale = select_language_according_to_priority
+    else
+      ::I18n.locale = default_language
+    end
+
+    locale = session[:locale] = ::I18n.locale
+    logger.info("Set locale to #{locale}")
+  end
+
+end