Migrating Blob avatar and profile images

vBulletin stores the avatar and profile images in 'blob' fields (filedata). The following vbulletin_blob.inc can be used to get them into Drupal

// vBulletinBlobMigration will behave exactly like the Migration class

class vBulletinBlobMigration extends Migration {
  public function __construct() {
    parent::__construct();

// Describe the class for the Migrate UI and set the default language to English

    $this->description = t('Migrate vBulletin user avatars');

    $this->defaultLanguage = 'en';

// Specify any dependencies on other classes to ensure that they are migrated before this one


// Specify the source user table with vb_ prefix from above and identify source fields ordered by ascending userid

    $query = Database::getConnection('default', 'for_migrate_vbulletin')
      ->select('customavatar', 'v')
      ->fields('v', array(
        'userid',
        'filedata',
        'dateline',
        'filename',
        'visible',
        'filesize',
        'width',
        'height',
        'filedata_thumb',
        'width_thumb',
        'height_thumb',
        ));

// Use the constructed query to create a MigrateSourceSQL and save it in the vBulletinBlobMigration object

    $this->source = new MigrateSourceSQL($query, array(), NULL, array('map_joinable' => FALSE));

// Specify that we want to create files from the blob source data

    $this->destination = new MigrateDestinationFile('file', 'MigrateFileBlob');

// Remember what source record created each destination object and track migration status and allow rollback with MigrateSQLMap class 

    $this->map = new MigrateSQLMap(
      $this->machineName,
      array(
        'userid' => array(
          'type' => 'int',
          'unsigned' => TRUE,
          'not null' => TRUE,
          'description' => 'vBulletin Unique user ID',
          'alias' => 'u',
        ),
      ),
      MigrateDestinationFile::getKeySchema()
    );

// For each source row define data mappings to the destination field from the source field

    $this->addFieldMapping('uid', 'userid');

    $this->addFieldMapping('value', 'filedata')
         ->description('An image blob in the DB');

    $this->addFieldMapping('timestamp', 'dateline');

    $this->addFieldMapping('destination_file', 'filename');

    $this->addFieldMapping('destination_dir')
        ->defaultValue('public://avatars');

// Do not map the following destination fields

// Do not map the following source fields
    
    } // close the public function construct

} // close the vBulletinBlobMigration class