Creating multilingual variables

A super quick blast from the past today; a Drupal 7 based article!

I had some work recently to create a new "setting" variable for one our Drupal 7 multilingual sites, which meant creating multilingual versions of those variables. I soon found out that there is very much a correct way - or order - to achieve this as I got this one very wrong (I had to re-instate my DB!). So here I am writing a very quick guide to help those from my wrong doings.

(This guide assumes you have a multilingual site setup with i18n's Variable translation module.)

Four simple steps to achieve a multilingual variable:

1. Declare your new variables via hook_variable_info

function your_module_name_variable_info($options = array()) {
  $variables['your_variable_name'] = array(
    'title' => t('Foo'),
    'description' => t('A multi-lingual variable'),
    'type' => 'string',
    'default' => t('Bar'),
    'localize' => TRUE,
  );
}

The options you can set in this hook are well documented - start reading from the Variable module's project page.

2. Flush the variable cache and get your new variables registered using an update hook. The meat of the update hook is below -- note that this assumes you want all of the possibly-localizable variables to be made translatable:

  variable_cache_clear();
  /** @var VariableRealmControllerInterface $controller */
  if ($controller = variable_realm_controller('language')) {
    $variables = $controller->getAvailableVariables();
    $controller->setRealmVariable('list', $variables);
  }
  else {
    throw new DrupalUpdateException('Could not set up translatable variables. Try manually setting them.');
  }

3. Create or alter your settings form (I'm assuming it uses system_settings_form() or is already recognised by the i18n/variable systems as a form containing translatable variables) and add your new form elements. Make sure the element(s) are the same as your newly created variable(s) - I use a $key variable to avoid any mistakes there!

$key = 'your_variable_name';
$form[$key] = array(
  '#type' => 'textfield',
  '#title' => t('Foo'),
  '#default_value' => variable_get($key, 'Bar'),
);

Head over to /admin/config/regional/i18n/variable or your settings form to see your new multilingual variable in all it's glory!