Translation of ActionController error messages with I18n

Question

I've got a problem with I18n. I can't find the right way to translate the ActionController error messages like

The action '...' could not be found for ...Controller

I can't found a translation in any of this example files in this repository: https://github.com/svenfuchs/rails-i18n/blob/master/rails/locale/en.yml

I found a solution for validation errors etc, but not for this kind of errors.

Is it possible to translate this kind of error messages with I18n files?

update: I want to translate them because they are shown to the user. I did it like in this railscast: http://railscasts.com/episodes/53-handling-exceptions-revised

All exceptions are processed by the railsapp itself instead through middelware with this configuration:

config.exceptions_app = self.routes

Then are all exceptions routed to a single action:

match '(errors)/:status', to: 'errors#show', constraints: {status: /\d{3}/} # via: :all

In this action the error message is used by an variable:

def show
  @exception = env["action_dispatch.exception"]
  respond_to do |format|
    format.html { render action: request.path[1..-1] }
    format.json { render json: {status: request.path[1..-1], error: @exception.message} }
  end
end

This variable is then shown in the production view:

<h1>Forbidden.</h1>
<% if @exception %>
  <p><%= @exception.message %></p>
<% else %>
  <p>You are not authorized to perform that action.</p>
<% end %>

Now the error message is dynamic. I think in general it is a good thing, because the user gets more information what went wrong and how to behave to avoid the specific error. But It is a tad too much information. I don't want them to see e.g. which controller processed the action. Therefore I want to "translate" the error messages to a safer variant of them.

Answer 1

You can use the exception class name as a key for your I18n translations. That way, you can have in your translations files a key-value pair using the exception class name (essentially what the exception was) and then using your own words for that specific exception.

I18n.t(@exception.class.name.underscore, default: "Generic Error")