Since version 2.2, Ruby on Rails comes with an integrated support for internationalization (I18n) which makes developing multi-language websites very easy. Here’s how it works.
Recently I worked on a project where I used the I18n API to provide multi-language support. The website had a user system and the user was able to change the web-site’s language in his/her profile. Basically, there was a model “User” with an attribute “language”, which was stored in the database. Every time when a user would log in on the website, the web-site’s language would change to the user’s preset language with:
I18n.locale = current_user.language
However, there was a problem with the emails, which a user automatically received from the web-site. I used a cron-job with Rails’ “script/runner” to periodically send mails from a model like this:
User.all( :conditions => "want_mail = 1" ).each do |user|
The mail template was translated with the Rails I18n API like this:
<%= I18n.t 'daily_mail.hello' + @user.name %>
The problem was only that the mails were sent out in English because the web-sites default language (I18n.default_locale) was English and there was no “I18n.locale” set in “script/runner”.
The easiest solution to that problem is to set the locale somewhere in your email setup:
class UserMailer < ActionMailer::Base
I18n.locale = user.language
@recipients = user.email
@from = "The Daily Mailer <email@example.com>"
@subject = I18n.t 'daily_mail.subject'
@sent_on = Time.now
@body[:user] = user
Alternatively, it’s possible to set the language in the email template:
<%= I18n.t('daily_mail.hello', :locale => @user.locale) + @user.name %>
It’s more a logical then a technical problem, but it shows how (logically) complicated multi-language web-sites can be.