问作为迁移过程的一部分，将url别名从drupal6迁移到drupal7

EN

/**
 * Implements hook_token_info().
 */
function custom_configuration_token_info() {  
  $type = array(
    'node' => array (
      'name' => t('Nodes'), 
      'description' => t('Tokens related to individual nodes.'), 
      'needs-data' => 'node',
     ),

         'term' => array(
           'name' => t('Taxonomy Terms'),
           'description' => t('Tokens related to taxonomy terms.'),
           'needs-data' => 'term',
         )
      );

      // tokens for node legacy nid.
      $tokens['node']['mapid'] = array(
        'name' => t("mapid"), 
        'description' => t("The nid of the node prior to migration."),
      );

      $tokens['term']['mapid'] = array(
        'name' => t('mapid'),
        'description' => t('The tid of taxonomy terms prior to migration.'),
      );

      return array(
        'types' => $type, 
        'tokens' => $tokens,
      );
    }


    now,

    function custom_configuration_tokens($type, $tokens, array $data = array(), array $options = array()) {
      $url_options = array('absolute' => TRUE);
      if (isset($options['language'])) {
        $url_options['language'] = $options['language'];
        $language_code = $options['language']->language;
      }
      else {
        $language_code = NULL;
      }
      $sanitize = !empty($options['sanitize']);

      $replacements = array();

      if ($type == 'node' && !empty($data['node'])) {
        $node = $data['node'];

        foreach ($tokens as $name => $original) {
              switch ($name) {

    <write your custom code for the token conditioned by the name attribute in info function>

        }
      }
    }

$this->addFieldMapping('path', 'my_legacy_alias_field');

class MyNodeMigration extends Migration {
  public function __construct(array $arguments) {
    $this->arguments = $arguments;
    parent::__construct();
    $source_fields = array('nid' => t('The node ID of the page'));

    $query = Database::getConnection('default', 'legacy')
      ->select('node', 'n')
      ->fields('n');
    $query->join('url_alias', 'a', "a.src = CONCAT('node/', n.nid)");
    $query->addField('a', 'dst');
    $this->source = new MigrateSourceSQL($query, $source_fields);
    $this->destination = new MigrateDestinationNode('my_node_type');
    $this->map = new MigrateSQLMap($this->machineName,
      array('nid' => array(
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'description' => 'D6 Unique Node ID',
        'alias' => 'n',
      )),
      MigrateDestinationNode::getKeySchema()
    );

    $this->addSimpleMappings(array('title', 'created', 'changed', 'status'));
    $this->addUnmigratedDestinations(array('sticky', 'log', 'nid'));
    $this->addFieldMapping('path', 'dst');
    $this->addFieldMapping('is_new')->defaultValue(TRUE);
  }
}