class HistoryController

class HistoryController extends ControllerBase {
    
    /**
     * Returns a set of nodes' last read timestamps.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The request of the page.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     *   The JSON response.
     */
    public function getNodeReadTimestamps(Request $request) {
        if ($this->currentUser()
            ->isAnonymous()) {
            throw new AccessDeniedHttpException();
        }
        if (!$request->request
            ->has('node_ids')) {
            throw new NotFoundHttpException();
        }
        $nids = $request->request
            ->all('node_ids');
        return new JsonResponse(history_read_multiple($nids));
    }
    
    /**
     * Marks a node as read by the current user right now.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   The request of the page.
     * @param \Drupal\node\NodeInterface $node
     *   The node whose "last read" timestamp should be updated.
     */
    public function readNode(Request $request, NodeInterface $node) {
        if ($this->currentUser()
            ->isAnonymous()) {
            throw new AccessDeniedHttpException();
        }
        // Update the history table, stating that this user viewed this node.
        history_write($node->id());
        return new JsonResponse((int) history_read($node->id()));
    }

}