class DatabaseTestController

class DatabaseTestController extends ControllerBase {
    
    /**
     * The database connection.
     *
     * @var \Drupal\Core\Database\Connection
     */
    protected $connection;
    
    /**
     * Constructs a DatabaseTestController object.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   A database connection.
     */
    public function __construct(Connection $connection) {
        $this->connection = $connection;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('database'));
    }
    
    /**
     * Runs a pager query and returns the results.
     *
     * This function does care about the page GET parameter, as set by the
     * test HTTP call.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     */
    public function pagerQueryEven($limit) {
        $query = $this->connection
            ->select('test', 't');
        $query->fields('t', [
            'name',
        ])
            ->orderBy('age');
        // This should result in 2 pages of results.
        $query = $query->extend(PagerSelectExtender::class)
            ->limit($limit);
        $names = $query->execute()
            ->fetchCol();
        return new JsonResponse([
            'names' => $names,
        ]);
    }
    
    /**
     * Runs a pager query and returns the results.
     *
     * This function does care about the page GET parameter, as set by the
     * test HTTP call.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     */
    public function pagerQueryOdd($limit) {
        $query = $this->connection
            ->select('test_task', 't');
        $query->fields('t', [
            'task',
        ])
            ->orderBy('pid');
        // This should result in 4 pages of results.
        $query = $query->extend(PagerSelectExtender::class)
            ->limit($limit);
        $names = $query->execute()
            ->fetchCol();
        return new JsonResponse([
            'names' => $names,
        ]);
    }
    
    /**
     * Runs a tablesort query and returns the results.
     *
     * This function does care about the page GET parameter, as set by the
     * test HTTP call.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     */
    public function testTablesort() {
        $header = [
            'tid' => [
                'data' => t('Task ID'),
                'field' => 'tid',
                'sort' => 'desc',
            ],
            'pid' => [
                'data' => t('Person ID'),
                'field' => 'pid',
            ],
            'task' => [
                'data' => t('Task'),
                'field' => 'task',
            ],
            'priority' => [
                'data' => t('Priority'),
                'field' => 'priority',
            ],
        ];
        $query = $this->connection
            ->select('test_task', 't');
        $query->fields('t', [
            'tid',
            'pid',
            'task',
            'priority',
        ]);
        $query = $query->extend(TableSortExtender::class)
            ->orderByHeader($header);
        // We need all the results at once to check the sort.
        $tasks = $query->execute()
            ->fetchAll();
        return new JsonResponse([
            'tasks' => $tasks,
        ]);
    }
    
    /**
     * Runs a tablesort query with a second order_by after and returns the results.
     *
     * This function does care about the page GET parameter, as set by the
     * test HTTP call.
     *
     * @return \Symfony\Component\HttpFoundation\JsonResponse
     */
    public function testTablesortFirst() {
        $header = [
            'tid' => [
                'data' => t('Task ID'),
                'field' => 'tid',
                'sort' => 'desc',
            ],
            'pid' => [
                'data' => t('Person ID'),
                'field' => 'pid',
            ],
            'task' => [
                'data' => t('Task'),
                'field' => 'task',
            ],
            'priority' => [
                'data' => t('Priority'),
                'field' => 'priority',
            ],
        ];
        $query = $this->connection
            ->select('test_task', 't');
        $query->fields('t', [
            'tid',
            'pid',
            'task',
            'priority',
        ]);
        $query = $query->extend(TableSortExtender::class)
            ->orderByHeader($header)
            ->orderBy('priority');
        // We need all the results at once to check the sort.
        $tasks = $query->execute()
            ->fetchAll();
        return new JsonResponse([
            'tasks' => $tasks,
        ]);
    }

}