Skip to content
Rails: FastGettext, I18n integration -- simple, threadsafe and fast!
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.


Simple FastGettext / Rails integration.

Do all translations you want with FastGettext, use any other I18n backend as extension/fallback.

Rails does: I18n.t('weir.rails.syntax.i.hate')
We do: _('Just translate my damn text!')
To use I18n calls define a weir.rails.syntax.i.hate translation.

See it working in the example application.



As plugin: script/plugin install git:// Or Gem: sudo gem install gettext_i18n_rails

FastGettext: sudo gem install fast_gettext

Want to find used messages in your ruby files ?

GetText 1.93 or GetText 2.0: sudo gem install gettext
GetText 2.0 will render 1.93 unusable, so only install if you do not have apps that use 1.93!

sudo gem install ruby_parser

Locales & initialisation

Copy default locales with dates/sentence-connectors/AR-errors you want from e.g. rails i18n into 'config/locales'

#environment.rb do |config|
  config.gem "fast_gettext", :version => '>=0.4.8'
  #only used for mo/po file generation in development, !do not load(:lib=>false), will needlessly eat ram!
  config.gem "gettext", :lib => false, :version => '>=1.9.3'
  # with bundler this would be
  # gem "fast_gettext", '>=0.4.8'
  # gem '>=1.9.3', "gettext", :require => false

FastGettext.add_text_domain 'app', :path => 'locale'
FastGettext.default_available_locales = ['en','de'] #all you want to allow
FastGettext.default_text_domain = 'app'

class ApplicationController < ...
  before_filter :set_gettext_locale


Getting started

Option A: Traditional mo/po files

  • use some _('translations')
  • run rake gettext:find, to let GetText find all translations used
  • (optional) run rake gettext:store_model_attributes, to parse the database for columns that can be translated
  • if this is your first translation: cp locale/app.pot locale/de/app.po for every locale you want to use
  • translate messages in 'locale/de/app.po' (leave msgstr blank and msgstr == msgid)
    new translations will be marked "fuzzy", search for this and remove it, so that they will be used. Obsolete translations are marked with ~#, they usually can be removed since they are no longer needed
  • run rake gettext:pack to write GetText format translation files

Option B: Database

This is the most scalable method, since all translators can work simultanousely and online.

Most easy to use with the translation database Rails engine. FastGettext setup would look like: include FastGettext::TranslationRepository::Db.require_models #load and include default models FastGettext.add_text_domain 'app', :type=>:db, :model=>TranslationKey Translations can be edited under /translation_keys


I18n.locale <==> FastGettext.locale.to_sym
I18n.locale = :de <==> FastGettext.locale = 'de'

Any call to I18n that matches a gettext key will be translated through FastGettext.


Car|Model means Model in namespace Car.
You do not have to translate this into english "Model", if you use the namespace-aware translation s_('Car|Model') == 'Model' #when no translation was found

ActiveRecord - error messages

ActiveRecord error messages are translated through Rails::I18n, but model names and model attributes are translated through FastGettext. Therefore a validation error on a BigCar's wheels_size needs _('big car') and _('BigCar|Wheels size') to display localized.

The model/attribute translations can be found through rake gettext:store_model_attributes, (which ignores some commonly untranslated columns like id,type,xxx_count,...).

Error messages can be translated through FastGettext, if the ':message' is a translation-id or the matching Rails I18n key is translated. In any other case they go through the SimpleBackend.

Option A:

Define a translation for "I need my rating!" and use it as message. validates_inclusion_of :rating, :in=>1..5, :message=>N_('I need my rating!')

Option B:

Do not use :message validates_inclusion_of :rating, :in=>1..5 and make a translation for the I18n key: activerecord.errors.models.rating.attributes.rating.inclusion

Option C:

Add a translation to each config/locales/*.yml files en: activerecord: errors: models: rating: attributes: rating: inclusion: " -- please choose!" The rails I18n guide can help with Option B and C.


FastGettext supports pluralization n_('Apple','Apples',3) == 'Apples'

Unfound translations

Sometimes translations like _("x"+"u") cannot be fond. You have 4 options:

  • add N_('xu') somewhere else in the code, so the parser sees it
  • add N_('xu') in a totally seperate file like locale/unfound_translations.rb, so the parser sees it
  • use the gettext_test_log rails plugin to find all translations that where used while testing
  • add a Logger to a translation Chain, so every unfound translations is logged (example)


Michael Grosser
Hereby placed under public domain, do what you want, just do not hold me accountable...

Something went wrong with that request. Please try again.