function update_variables_to_config

Updates config with values set on Drupal 7.x.

Provides a generalised method to migrate variables from Drupal 7 to Drupal 8's configuration management system.

Parameters

string $config_name: The configuration object name to retrieve.

array $variable_map: An associative array that maps old variables names to new configuration object keys; e.g.:

array(
  'old_variable' => 'new_config.sub_key',
);

This would migrate the value contained in variable name 'old_variable' into the data key 'new_config.sub_key' of the configuration object $config_name.

File

drupal/core/includes/update.inc, line 1367

Drupal database update API.

Code

function update_variables_to_config($config_name, array $variable_map) {

  // Build the new configuration object.
  // This potentially loads an existing configuration object, in case another
  // update function migrated configuration values into $config_name already.
  $config = config($config_name);
  $original_data = $config
    ->get();

  // Extract the module namespace/owner from the configuration object name.
  $module = strtok($config_name, '.');

  // Load and set default configuration values.
  $file = new FileStorage(drupal_get_path('module', $module) . '/config');
  if (!$file
    ->exists($config_name)) {
    throw new ConfigException("Default configuration file {$config_name} for {$module} extension not found but is required to exist.");
  }
  $default_data = $file
    ->read($config_name);

  // Apply the default values.
  $config
    ->setData($default_data);

  // Merge any possibly existing original data into default values.
  // Only relevant when being called repetitively on the same config object.
  if (!empty($original_data)) {
    $config
      ->merge($original_data);
  }

  // Fetch existing variables.
  $variables = db_query('SELECT name, value FROM {variable} WHERE name IN (:variables)', array(
    ':variables' => array_keys($variable_map),
  ))
    ->fetchAllKeyed();

  // Set configuration values according to the provided variable mapping.
  foreach ($variable_map as $variable_name => $config_key) {

    // This function migrates variables regardless of their value, including
    // NULL values. Any possibly required customizations need to be performed
    // manually, either via variable_set() before calling this function or via
    // config() after calling this function.
    if (isset($variables[$variable_name])) {
      $value = unserialize($variables[$variable_name]);
      $config
        ->set($config_key, $value);
    }
  }

  // Save the configuration object.
  $config
    ->save();

  // Delete the migrated variables.
  db_delete('variable')
    ->condition('name', array_keys($variable_map), 'IN')
    ->execute();
}