sessionless-1.x-dev/src/Element/SessionlessElementTrait.php

<?php

namespace Drupal\sessionless\Element;

use Drupal\Core\Form\FormStateInterface;
use Drupal\sessionless\SessionlessEncryptAndSign;
use Drupal\sessionless\SessionlessInterface;
use Drupal\sessionless\SessionlessOnlySign;

trait SessionlessElementTrait {

  public function getInfo() {
    $class = static::class;
    return [
      '#input' => TRUE,
      '#pre_render' => [
        [$class, 'preRenderSessionless'],
      ],
    ];
  }

  protected static function getCryptoService(bool $mustEncrypt): SessionlessInterface {
    if ($mustEncrypt) {
      return  \Drupal::service(SessionlessEncryptAndSign::class);
    }
    else {
      return  \Drupal::service(SessionlessOnlySign::class);
    }
  }
  public static function preRenderSessionless($element) {
    $serialized = serialize($element['#value'] ?? NULL);
    if (isset($serialized)) {
      $jwt = self::getCryptoService(self::mustEncrypt())
        ->encode($serialized);
      $element['hidden'] = [
        '#type' => 'hidden',
        '#name' => $element['#name'],
        '#value' => $jwt,
      ];
    }
    return $element;
  }

  public static function valueCallback(&$element, $input, FormStateInterface $form_state) {
    $value = NULL;
    if ($input) {
      $serialized = self::getCryptoService(self::mustEncrypt())
        ->decode($input);
      $value = unserialize($serialized);
    }
    return $value;
  }

  abstract protected static function mustEncrypt(): bool;

}