class UpdateKernel

class UpdateKernel extends DrupalKernel {
    
    /**
     * {@inheritdoc}
     */
    public function discoverServiceProviders() {
        parent::discoverServiceProviders();
        $this->serviceProviderClasses['app']['update_kernel'] = 'Drupal\\Core\\Update\\UpdateServiceProvider';
    }
    
    /**
     * {@inheritdoc}
     */
    protected function initializeContainer() {
        // Always force a container rebuild, in order to be able to override some
        // services, see \Drupal\Core\Update\UpdateServiceProvider.
        $this->containerNeedsRebuild = TRUE;
        $container = parent::initializeContainer();
        return $container;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function cacheDrupalContainer(array $container_definition) {
        // Don't save this particular container to cache, so it does not leak into
        // the main site at all.
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function handle(Request $request, $type = self::MAIN_REQUEST, $catch = TRUE) : Response {
        try {
            static::bootEnvironment();
            // First boot up basic things, like loading the include files.
            $this->initializeSettings($request);
            ReverseProxyMiddleware::setSettingsOnRequest($request, Settings::getInstance());
            $this->boot();
            $container = $this->getContainer();
            
            /** @var \Symfony\Component\HttpFoundation\RequestStack $request_stack */
            $request_stack = $container->get('request_stack');
            $request_stack->push($request);
            $this->preHandle($request);
            // Handle the actual request. We need the session both for authentication
            // as well as the DB update, like
            // \Drupal\system\Controller\DbUpdateController::batchFinished.
            $this->bootSession($request);
            $result = $this->handleRaw($request);
            $this->shutdownSession($request);
            return $result;
        } catch (\Exception $e) {
            return $this->handleException($e, $request, $type);
        }
    }
    
    /**
     * Generates the actual result of update.php.
     *
     * The actual logic of the update is done in the db update controller.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The incoming request.
     *
     * @return \Symfony\Component\HttpFoundation\Response
     *   A response object.
     *
     * @see \Drupal\system\Controller\DbUpdateController
     */
    protected function handleRaw(Request $request) {
        $container = $this->getContainer();
        $this->handleAccess($request);
        
        /** @var \Drupal\Core\Controller\ControllerResolverInterface $controller_resolver */
        $controller_resolver = $container->get('controller_resolver');
        
        /** @var callable $db_update_controller */
        $db_update_controller = $controller_resolver->getControllerFromDefinition('\\Drupal\\system\\Controller\\DbUpdateController::handle');
        $this->setupRequestMatch($request);
        
        /** @var \Symfony\Component\HttpKernel\Controller\ArgumentResolverInterface $argument_resolver */
        $argument_resolver = $container->get('http_kernel.controller.argument_resolver');
        $arguments = $argument_resolver->getArguments($request, $db_update_controller);
        return call_user_func_array($db_update_controller, $arguments);
    }
    
    /**
     * Boots up the session.
     *
     * This method + shutdownSession() basically simulates what
     * \Drupal\Core\StackMiddleware\Session does.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The incoming request.
     */
    protected function bootSession(Request $request) {
        $container = $this->getContainer();
        
        /** @var \Symfony\Component\HttpFoundation\Session\SessionInterface $session */
        $session = $container->get('session');
        $session->start();
        $request->setSession($session);
    }
    
    /**
     * Ensures that the session is saved.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The incoming request.
     */
    protected function shutdownSession(Request $request) {
        $request->getSession()
            ->save();
    }
    
    /**
     * Set up the request with fake routing data for update.php.
     *
     * This fake routing data is needed in order to make batch API work properly.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The incoming request.
     */
    protected function setupRequestMatch(Request $request) {
        $path = $request->getPathInfo();
        $args = explode('/', ltrim($path, '/'));
        $request->attributes
            ->set(RouteObjectInterface::ROUTE_NAME, 'system.db_update');
        $request->attributes
            ->set(RouteObjectInterface::ROUTE_OBJECT, $this->getContainer()
            ->get('router.route_provider')
            ->getRouteByName('system.db_update'));
        $op = $args[0] ?: 'info';
        $request->attributes
            ->set('op', $op);
        $request->attributes
            ->set('_raw_variables', new InputBag([
            'op' => $op,
        ]));
    }
    
    /**
     * Checks if the current user has rights to access updates page.
     *
     * If the current user does not have the rights, an exception is thrown.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The incoming request.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
     *   Thrown when update.php should not be accessible.
     */
    protected function handleAccess(Request $request) {
        
        /** @var \Drupal\Core\Authentication\AuthenticationManager $authentication_manager */
        $authentication_manager = $this->getContainer()
            ->get('authentication');
        $account = $authentication_manager->authenticate($request) ?: new AnonymousUserSession();
        
        /** @var \Drupal\Core\Session\AccountProxyInterface $current_user */
        $current_user = $this->getContainer()
            ->get('current_user');
        $current_user->setAccount($account);
        
        /** @var \Drupal\system\Access\DbUpdateAccessCheck $db_update_access */
        $db_update_access = $this->getContainer()
            ->get('access_check.db_update');
        if (!Settings::get('update_free_access', FALSE) && !$db_update_access->access($account)
            ->isAllowed()) {
            throw new AccessDeniedHttpException('In order to run update.php you need to either have "Administer software updates" permission or have set $settings[\'update_free_access\'] in your settings.php.');
        }
    }

}