PageExampleController.php

<?php

namespace Drupal\page_example\Controller;

use Drupal\Core\Controller\ControllerBase;
use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;
use Drupal\examples\Utility\DescriptionTemplateTrait;

/**
 * Controller routines for page example routes.
 */
class PageExampleController extends ControllerBase {
    use DescriptionTemplateTrait;
    
    /**
     * {@inheritdoc}
     */
    protected function getModuleName() {
        return 'page_example';
    }
    
    /**
     * Constructs a simple page.
     *
     * The router _controller callback, maps the path
     * 'examples/page-example/simple' to this method.
     *
     * _controller callbacks return a renderable array for the content area of the
     * page. The theme system will later render and surround the content with the
     * appropriate blocks, navigation, and styling.
     */
    public function simple() {
        return [
            '#markup' => '<p>' . $this->t('Simple page: The quick brown fox jumps over the lazy dog.') . '</p>',
        ];
    }
    
    /**
     * A more complex _controller callback that takes arguments.
     *
     * This callback is mapped to the path
     * 'examples/page-example/arguments/{first}/{second}'.
     *
     * The arguments in brackets are passed to this callback from the page URL.
     * The placeholder names "first" and "second" can have any value but should
     * match the callback method variable names; i.e. $first and $second.
     *
     * This function also demonstrates a more complex render array in the returned
     * values. Instead of rendering the HTML with theme('item_list'), content is
     * left un-rendered, and the theme function name is set using #theme. This
     * content will now be rendered as late as possible, giving more parts of the
     * system a chance to change it if necessary.
     *
     * Consult @link http://drupal.org/node/930760 Render Arrays documentation
     * @endlink for details.
     *
     * @param string $first
     *   A string to use, should be a number.
     * @param string $second
     *   Another string to use, should be a number.
     *
     * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
     *   If the parameters are invalid.
     */
    public function arguments($first, $second) {
        // Make sure you don't trust the URL to be safe! Always check for exploits.
        if (!is_numeric($first) || !is_numeric($second)) {
            // We will just show a standard "access denied" page in this case.
            throw new AccessDeniedHttpException();
        }
        $list[] = $this->t("First number was @number.", [
            '@number' => $first,
        ]);
        $list[] = $this->t("Second number was @number.", [
            '@number' => $second,
        ]);
        $list[] = $this->t('The total was @number.', [
            '@number' => $first + $second,
        ]);
        $render_array['page_example_arguments'] = [
            // The theme function to apply to the #items.
'#theme' => 'item_list',
            // The list itself.
'#items' => $list,
            '#title' => $this->t('Argument Information'),
        ];
        return $render_array;
    }

}