Plugin: translatable_columns

Written on 6 September, 2008

It was just three days ago when I discussed how to translate columns. At the moment I was writing it, I was already thinking: "this should be a plugin". So today, I took the liberty and created it.

Installing

First make sure you're running Rails 2.2 or edge:

rake rails:freeze:edge

Install the plugin:

./script/plugin install git://github.com/iain/translatable_columns.git

Create or modify a model to have multiple columns for one attribute:

./script/generate model Topic title_en:string title_nl:string title_de:string title_fr:string

Usage

Identify the columns you want to translate:

class Topic < ActiveRecord::Base
  translatable_columns :title
end

And you're done!

Create a form like this:

<% form_for(@topic) do |f| %>
  <%= f.text_field :title %>
<% end %>

And it will save to whatever locale is set in I18n. No hard feelings, nothing to worry about.

Validating

Validation is of course built in. If you want to validate the presence of at least one of the translations, just call validates_translation_of:

class Topic < ActiveRecord::Base
  translatable_columns :title
  validates_translation_of :title
end

This will make your record invalid when none of the translated columns exist. It works exactly as validates_presence_of, including all its options!

Customizing

You can change the settings of translatable_columns on both a global level and at individual attribute level. There are two configuration options at the moment, called full_locale and use_default.

Set the global configuration in your environment file:

# These are the defaults of translatable_columns:
ActiveRecord::Base.translatable_columns_config.full_locale = false
ActiveRecord::Base.translatable_columns_config.use_default = true

full_locale

With this option you can change which part of the locale is used in the columns. Default is false, so only the first part of the locale is expected in the column. So a title for en-US is called title_en and a title for en-GB is also called title_en. When you set full_locale to true, it uses the entire locale, substituting the hyphen with an underscore. This way a title for en-US is called title_en_us and a title for en-GB is called title_en_gb.

full_locale cannot be set per attribute just now.

use_default

With this option you can specify which value will be returned automatically if no proper value has been found. Default is true, so it will try harder to find a value. It might even be a value in another language.

You can set this option per attribute if you'd like, to override the global config.

class Topic < ActiveRecord::Base
  translatable_columns :title, :use_default => false
end

Some extras

What if the user has selected a locale which you don't have in the database? In this case it'll get the column belonging to the I18n.default_locale. Make sure you have a column for this locale, because you'll be serving a nasty error if even this one isn't present!

You might want to provide multiple languages for a user to fill in at once. This is one way to do it:

<% form_for(@topic) do |f| %>
  <% Topic.available_translatable_columns_of(:title).each do |attribute| %>
    <%= f.text_field attribute %>
  <% end %>
<% end %>

Happy devving!

# iain.nl