Issue #2953246 by abramm, max-kuzomko, greggles, jnettik: Add a migrate...

<?php

namespace Drupal\email_registration\Plugin\migrate\process;

use Drupal\migrate\ProcessPluginBase;

use Drupal\migrate\MigrateExecutableInterface;

use Drupal\migrate\Row;

/**

 * Transforms the user email to a user name.

 *

 * @code

 * process:

 *   name:

 *     plugin: email_registration_user_name

 *     source: username

 * @endcode

 *

 * Note: unlike normal Email Registration module, this plugin does NOT ensure

 * the username is unique, so be sure to use 'make_unique_entity_field'

 * processor like this:

 *

 * @code

 * process:

 *   format:

 *   -

 *     plugin: email_registration_user_name

 *     source: username

 *   -

 *     plugin: make_unique_entity_field

 *     entity_type: user

 *     field: name

 *     postfix: _

 * @endcode

 *

 * @see email_registration_user_insert().

 *

 * @MigrateProcessPlugin(

 *   id = "email_registration_user_name"

 * )

 */

class EmailRegistrationUserName extends ProcessPluginBase {

  /**

   * {@inheritdoc}

   */

  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {

    // Strip off everything after the @ sign.

    $new_name = preg_replace('/@.*$/', '', $value);

    // Clean up the username.

    return email_registration_cleanup_username($new_name);

  }

}