Drupal 8 Webform Redirect Handler supports tokens

RedirectWebformHandler.php

<?php

namespace Drupal\CUSTOM_MODULE\Plugin\WebformHandler;

use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Logger\LoggerChannelFactoryInterface;
use Drupal\Core\Url;
use Drupal\webform\Plugin\WebformHandlerBase;
use Drupal\webform\WebformSubmissionConditionsValidatorInterface;
use Drupal\webform\WebformSubmissionInterface;
use Drupal\webform\WebformTokenManagerInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Webform submission redirect handler.
 *
 * @WebformHandler(
 *   id = "redirect",
 *   label = @Translation("Redirect"),
 *   category = @Translation("Development"),
 *   description = @Translation("Redirect after webform submission."),
 *   cardinality = \Drupal\webform\Plugin\WebformHandlerInterface::CARDINALITY_SINGLE,
 *   results = \Drupal\webform\Plugin\WebformHandlerInterface::RESULTS_PROCESSED,
 *   submission = \Drupal\webform\Plugin\WebformHandlerInterface::SUBMISSION_OPTIONAL,
 * )
 */
class RedirectWebformHandler extends WebformHandlerBase {

  /**
   * The webform token manager.
   *
   * @var \Drupal\webform\WebformTokenManagerInterface
   */
  protected $tokenManager;

  /**
   * RedirectWebformHandler constructor.
   *
   * @param array $configuration
   * @param $plugin_id
   * @param $plugin_definition
   * @param \Drupal\Core\Logger\LoggerChannelFactoryInterface $logger_factory
   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   * @param \Drupal\webform\WebformSubmissionConditionsValidatorInterface $conditions_validator
   * @param \Drupal\webform\WebformTokenManagerInterface $token_manager
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, LoggerChannelFactoryInterface $logger_factory, ConfigFactoryInterface $config_factory, EntityTypeManagerInterface $entity_type_manager, WebformSubmissionConditionsValidatorInterface $conditions_validator, WebformTokenManagerInterface $token_manager) {
    parent::__construct($configuration, $plugin_id, $plugin_definition, $logger_factory, $config_factory, $entity_type_manager, $conditions_validator);
    $this->tokenManager = $token_manager;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->get('logger.factory'),
      $container->get('config.factory'),
      $container->get('entity_type.manager'),
      $container->get('webform_submission.conditions_validator'),
      $container->get('webform.token_manager')
    );
  }

  /**
   * {@inheritdoc}
   */
  public function getSummary() {
    $configuration = $this->getConfiguration();
    $settings = $configuration['settings'];

    // Get state labels.
    $states = [
      WebformSubmissionInterface::STATE_DRAFT_CREATED => $this->t('Draft created'),
      WebformSubmissionInterface::STATE_DRAFT_UPDATED => $this->t('Draft updated'),
      WebformSubmissionInterface::STATE_CONVERTED     => $this->t('Converted'),
      WebformSubmissionInterface::STATE_COMPLETED     => $this->t('Completed'),
      WebformSubmissionInterface::STATE_UPDATED       => $this->t('Updated'),
      WebformSubmissionInterface::STATE_LOCKED        => $this->t('Locked'),
    ];
    $settings['states'] = array_intersect_key($states, array_combine($settings['states'], $settings['states']));

    return [
        '#settings' => $settings,
      ] + parent::getSummary();
  }

  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration() {
    return [
      'states' => [WebformSubmissionInterface::STATE_COMPLETED],
      'url'    => '/webform/[webform:id]/submissions/[webform_submission:sid]',
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    $results_disabled = $this->getWebform()->getSetting('results_disabled');

    $form['trigger'] = [
      '#type'  => 'fieldset',
      '#title' => $this->t('Trigger'),
    ];

    $form['trigger']['states'] = [
      '#type'          => 'checkboxes',
      '#title'         => $this->t('Execute'),
      '#options'       => [
        WebformSubmissionInterface::STATE_DRAFT_CREATED => $this->t('…when <b>draft is created</b>.'),
        WebformSubmissionInterface::STATE_DRAFT_UPDATED => $this->t('…when <b>draft is updated</b>.'),
        WebformSubmissionInterface::STATE_CONVERTED     => $this->t('…when anonymous <b>submission is converted</b> to authenticated.'),
        WebformSubmissionInterface::STATE_COMPLETED     => $this->t('…when <b>submission is completed</b>.'),
        WebformSubmissionInterface::STATE_UPDATED       => $this->t('…when <b>submission is updated</b>.'),
      ],
      '#required'      => TRUE,
      '#access'        => $results_disabled ? FALSE : TRUE,
      '#default_value' => $results_disabled ? [WebformSubmissionInterface::STATE_COMPLETED] : $this->configuration['states'],
    ];

    $form['redirect'] = [
      '#type'  => 'fieldset',
      '#title' => $this->t('Redirect'),
    ];

    $form['redirect']['url'] = [
      '#type'          => 'textfield',
      '#title'         => $this->t('URL'),
      '#required'      => TRUE,
      '#access'        => $results_disabled ? FALSE : TRUE,
      '#default_value' => $results_disabled ? '' : $this->configuration['url'],
    ];

    $form['redirect']['token_tree_link'] = $this->buildTokenTreeElement();

    $this->elementTokenValidate($form);

    return $this->setSettingsParents($form);
  }

  /**
   * {@inheritdoc}
   */
  public function validateConfigurationForm(array &$form, FormStateInterface $form_state) {
    if ($form_state->hasAnyErrors()) {
      return;
    }
  }

  /**
   * {@inheritdoc}
   */
  public function submitConfigurationForm(array &$form, FormStateInterface $form_state) {
    parent::submitConfigurationForm($form, $form_state);
    $this->applyFormStateToConfiguration($form_state);
    // Cleanup states.
    $this->configuration['states'] = array_values(array_filter($this->configuration['states']));
  }

  /**
   * {@inheritdoc}
   */
  public function alterForm(array &$form, FormStateInterface $form_state, WebformSubmissionInterface $webform_submission) {
    // Flag the button as submit button.
    $form['actions']['submit']['#submit_button'] = TRUE;
    // Append a custom callback function to handle redirect in it.
    $form['actions']['submit']['#submit'][] = [$this, 'submitFormRedirect'];
  }

  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state, WebformSubmissionInterface $webform_submission) {
    $webform = $webform_submission->getWebform();
    $results_disbled = $webform->getSetting('results_disabled');
    $state = $results_disbled ? WebformSubmissionInterface::STATE_COMPLETED : $webform_submission->getState();
    $element = $form_state->getTriggeringElement();

    // If a draft has been submitted without any kind of errors, than the
    // status is completed, not updated.
    if ($state == 'updated' && !empty($element['#submit_button'])) {
      $state = (!$webform_submission->isDraft() && !$webform_submission->isCompleted()) ? WebformSubmissionInterface::STATE_COMPLETED : $state;
    }

    if (in_array($state, $this->configuration['states'])) {
      $url = $this->replaceTokens($this->configuration['url'], $webform_submission);

      // Redirecting required.
      $form_state->setValue('redirect', TRUE);
      $form_state->setValue('redirect_url', $url);
    }
  }

  /**
   * Custom callback function to handle redirection.
   *
   * @param array $form
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   */
  public function submitFormRedirect(array &$form, FormStateInterface $form_state) {
    $url = $form_state->getValue('redirect_url');

    if (!empty($form_state->getValue('redirect')) && !empty($url)) {
      if (strpos($url, 'http') === 0) {
        $url = Url::fromUri($url);
      }
      elseif (strpos($url, '/') === 0 || strpos($url, '?') === 0 || strpos($url, '#') === 0) {
        $url = Url::fromUserInput($url);
      }

      if ($url instanceof Url) {
        $form_state->setRedirectUrl($url);
      }
    }
  }

}