Gettext and Rails

I encountered some problems with gettext rails integration recently, so here they are with explanation and resolution (if I found it).

Localization of ActiveRecordHelper error messages :

I choose to change the error message as explained by the gettext tutorial :

in application.rb

ActionView::Helpers::ActiveRecordHelper::L10n.set_error_message_title(Nn_("An error is occured", "%{num} errors are occured"))  
ActionView::Helpers::ActiveRecordHelper::L10n.set_error_message_explanation(Nn_("The error is:", "The errors are:"))

this works great, the error message displayed by the helper is the good one… except it only appears in the base language (English in my case). And the text never appears in my .pot file. After some searches in the gettext files, I found the problem : the textdomain for the helper is ‘rails’, which is great because you got validations and errors localized by gettext team for free. But it means you can’t set your own message without modifying the rails.pot in gettext package, which is not a solution because you need to maintain your own gettext gem or apply modifications to all you servers installs, and no you can’t install gettext as a rails plugin as gettext gem compile a gettext.so|.dylib on install which depends of your system.

The solution ? I didn’t find any satisfying one, if you force the textdomain to your app’s one then you need to duplicate and update all the rails translations strings from gettext package.

Gettext#updatepo and models with observers :

One of gettext nifty feature is its ability to extract your model columns names for translation. But the implementation cause some trouble when you have declared some observers in your environment.rb.

To accomplish its tasks, gettext first load rails environment. Then each files are parsed by Gettext::ActiveRecordParser#parse where you have :

old_constants = Object.constants
begin
  eval(open(file).read, TOPLEVEL_BINDING)
rescue
  $stderr.puts _("Ignored '%{file}'. Solve dependencies first.") % {:file => file}
  $stderr.puts $! 
end
loaded_constants = Object.constants - old_constants

This code try to catch the constants the current file add to Object.constants and then parse them either as ruby or ActiveRecord subclass. But if you declared an observer in your environment.rb, the model and its observer is already in the Object.constants and are just ignored by the gettext active record parser.

Solution ? Comment the config.observers line in your environment.rb each time you need to run gettext:updatepo task, not really sexy but it works.[…]