Custom webform action - Download submissions from multiple webforms

DownloadSubmissions.php

<?php

// Made on request from a user on drupal slack.

// Not fully tested - I've stripped this from a module I made from a client and not tested it still works after
// removing some functionality specific to that site. 
// *Should work* and be a good starting point at least.

// Put this in a custom module - The example I took this from was called webfrom_extras.
// This may need minor modification - I've scrubbed data from it.
// Let me know if you have any issues.

namespace Drupal\webform_extras\Plugin\Action;

use Drupal\Core\Action\ActionBase;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Url;
use Drupal\webform\Controller\WebformResultsExportController;
use Drupal\webform\Entity\Webform;
use Drupal\webform\Entity\WebformSubmission;
use Symfony\Component\HttpFoundation\BinaryFileResponse;
use Symfony\Component\HttpFoundation\RedirectResponse;

/**
 * Locks a webform submission.
 *
 * @Action(
 *   id = "webform_submission_download_action",
 *   label = @Translation("Download submission"),
 *   type = "webform_submission"
 * )
 */
class DownloadSubmission extends ActionBase {

  /**
   * {@inheritdoc}
   */
  public function execute($entity = NULL) {
    $webformId = $entity->getWebform()->id();
    $sub = WebformSubmission::loadMultiple([$entity->id()]);
    /** @var \Drupal\webform\WebformInterface $webform */
    $webform = Webform::load($webformId);
    /** @var \Drupal\Core\Entity\EntityInterface|null $source_entity */
    $source_entity = \Drupal::entityTypeManager()->getStorage('webform_submission')->load($entity->id());
    /** @var \Drupal\webform\WebformSubmissionExporterInterface $submission_exporter */
    $submission_exporter = \Drupal::service('webform_submission.exporter');
    $submission_exporter->setWebform($webform);
    $default_options = $submission_exporter->getWebformOptions();
    /** @var array $export_options */
    $export_options = $default_options;
    // Always use Excel for this.
    $export_options['excel'] = 1;
    // Write the file.
    $submission_exporter->setSourceEntity($source_entity);
    $submission_exporter->setExporter($export_options);
    $submission_exporter->generate();
    $submission_exporter->writeHeader();
    $submission_exporter->writeRecords($sub);
    $submission_exporter->writeFooter();
    $submission_exporter->writeExportToArchive();
    // Download the file.
    $file_path = $submission_exporter->getArchiveFileName();
    $params = [
      'webform' => $webformId,
      'filename' => $file_path,
    ];
    $route_name = 'entity.webform.results_export_file';
    $redirect_url = Url::fromRoute($route_name, $params, ['absolute' => TRUE])->toString();
    $resp = new RedirectResponse($redirect_url);
    $resp->send();
  }

  /**
   * {@inheritdoc}
   */
  public function executeMultiple(array $entities) {
    // There is a bit of code duplication here between execute and
    // executemultiple. Lets rethink that.
    $existingWebformID = '';
    // Scrubbed this.
    $processingShouldContinue = true;
    if ($processingShouldContinue) {
      // Can we DI this?
      $exporter = \Drupal::service('webform_submission.exporter');
      // The important settings are all the same for all webforms at the moment
      // so we can just load the first.
      $webformId = current($entities)->getWebform()->id();
      /** @var \Drupal\webform\WebformInterface $webform */
      $webform = \Drupal::entityTypeManager()->getStorage('webform')->load($webformId);
      $exporter->setWebform($webform);
      /** @var \Drupal\Core\Entity\EntityInterface|null $source_entity */
      $source_entity = \Drupal::entityTypeManager()->getStorage('webform_submission')->load(current($entities)->id());
      // Can we DI this?
      /** @var \Drupal\webform\WebformSubmissionExporterInterface $submission_exporter */
      $submission_exporter = \Drupal::service('webform_submission.exporter');
      $submission_exporter->setWebform($webform);
      // Get the default option for the webform.
      $default_options = $submission_exporter->getWebformOptions();
      $export_options = $default_options;
      // Always use Excel for this.
      $export_options['excel'] = 1;
      // Create the export.
      $submission_exporter->setSourceEntity($source_entity);
      $submission_exporter->setExporter($export_options);
      $submission_exporter->generate();
      $submission_exporter->writeHeader();
      $submission_exporter->writeRecords($entities);
      $submission_exporter->writeFooter();
      $submission_exporter->writeExportToArchive();
      // Download the file.
      $file_path = $submission_exporter->getArchiveFileName();
      $params = [
        'webform' => $webformId,
        'filename' => $file_path,
      ];
      $route_name = 'entity.webform.results_export_file';
      $redirect_url = Url::fromRoute($route_name, $params, ['absolute' => TRUE])->toString();
      $resp = new RedirectResponse($redirect_url);
      $resp->send();
    }
  }

  /**
   * {@inheritdoc}
   */
  public function access($object, AccountInterface $account = NULL, $return_as_object = FALSE) {
    /** @var \Drupal\webform\WebformSubmissionInterface $object */
    $result = $object->locked->access('edit', $account, TRUE)
      ->andIf($object->access('update', $account, TRUE));

    return $return_as_object ? $result : $result->isAllowed();
  }
}