posthog-1.0.0-alpha5/src/CookieReader.php

<?php

declare(strict_types=1);

namespace Drupal\posthog;

use Drupal\Component\Serialization\Json;
use Drupal\Core\Config\ConfigFactoryInterface;
use Symfony\Component\HttpFoundation\RequestStack;

/**
 * Service for reading PostHog cookies.
 */
class CookieReader {

  /**
   * Constructs a CookieReader object.
   *
   * @param \Drupal\Core\Config\ConfigFactoryInterface $configFactory
   *   The config factory.
   * @param \Symfony\Component\HttpFoundation\RequestStack $requestStack
   *   The request stack.
   */
  public function __construct(
    protected readonly ConfigFactoryInterface $configFactory,
    protected readonly RequestStack $requestStack,
  ) {}

  /**
   * Gets the whole PostHog cookie.
   *
   * @return string|null
   *   The cookie value or NULL if not found.
   */
  public function getDecodedCookie(): ?array {
    $request = $this->requestStack->getCurrentRequest();
    if (empty($request)) {
      return NULL;
    }

    $cookieName = $this->getCookieName();
    $cookie = $request->cookies->get($cookieName);
    if (empty($cookie)) {
      return NULL;
    }

    return Json::decode($cookie);
  }

  /**
   * Gets the PostHog cookie name based on the API key.
   *
   * @return string
   *   The cookie name.
   */
  public function getCookieName(): string {
    $config = $this->configFactory->get('posthog.settings');
    $apiKey = $config->get('api_key');
    if (empty($apiKey)) {
      throw new \Exception('API key is not set in the configuration.');
    }
    return 'ph_' . $apiKey . '_posthog';
  }

  /**
   * Extracts the distinct ID from the PostHog cookie.
   *
   * Note, that even if we don't identify the user javascript-wise, we will
   * still receive a cookie with a distinct id.
   *
   * @return string|null
   *   The distinct ID or NULL if not found or extraction fails.
   */
  public function getDistinctIdByCookie(): ?string {
    $decodedCookie = $this->getDecodedCookie();
    // Use the distinct id from the cookie, if it is set:
    if (!empty($decodedCookie) && !empty($decodedCookie['distinct_id'])) {
      return $decodedCookie['distinct_id'];
    }

    return NULL;
  }

}