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Rails: FastGettext, I18n integration -- simple, threadsafe and fast!
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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'

If you are not using bundler:

#config/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'

If you are using bundler:

gem "fast_gettext", '>=0.4.8'
gem '>=1.9.3', "gettext", :require => false

If you installed it as a gem add to your Rakefile

  require "gettext_i18n_rails/tasks"
rescue LoadError
  puts "gettext_i18n_rails is not installed, you probably should run 'rake gems:install' or 'bundle install'."

To initialize:

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

And in your application:

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...

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