MenuExampleController.php

<?php

namespace Drupal\menu_example\Controller;

use Drupal\Core\Controller\ControllerBase;
use Drupal\Core\Link;
use Drupal\Core\Url;
use Drupal\examples\Utility\DescriptionTemplateTrait;

/**
 * Controller routines for menu example routes.
 *
 * The response of Drupal's HTTP Kernel system's request is generated by
 * a piece of code called the controller.
 *
 * In Drupal 8, we use a controller class
 * for placing those piece of codes in methods which responds to a route.
 *
 * This file will be placed at {module_name}/src/Controller directory. Route
 * entries uses a key '_controller' to define the method called from controller
 * class.
 *
 * @see https://www.drupal.org/docs/8/api/routing-system/introductory-drupal-8-routes-and-controllers-example
 */
class MenuExampleController extends ControllerBase {
    use DescriptionTemplateTrait;
    
    /**
     * {@inheritdoc}
     */
    protected function getModuleName() {
        return 'menu_example';
    }
    
    /**
     * Page callback for the simplest introduction menu entry.
     *
     * The controller callback defined menu_examples.routing.yml file,
     * maps the path 'examples/menu-example' to this method.
     *
     * @throws \InvalidArgumentException
     */
    public function basicInstructions() {
        return [
            $this->description(),
        ];
    }
    
    /**
     * Show a menu link in a menu other than the default "Navigation" menu.
     */
    public function alternateMenu() {
        return [
            '#markup' => $this->t('This will be in the Main menu instead of the default Tools menu'),
        ];
    }
    
    /**
     * A menu entry with simple permissions using 'access protected menu example'.
     *
     * @throws \InvalidArgumentException
     */
    public function permissioned() {
        $url = Url::fromRoute('examples.menu_example.permissioned_controlled');
        return [
            '#markup' => $this->t('A menu item that requires the "access protected menu example" permission is at @link', [
                '@link' => Link::createFromRoute($url->getInternalPath(), $url->getRouteName())
                    ->toString(),
            ]),
        ];
    }
    
    /**
     * Only accessible when the user will be granted with required permission.
     *
     * The permission is defined in file menu_examples.permissions.yml.
     */
    public function permissionedControlled() {
        return [
            '#markup' => $this->t('This menu entry will not show and the page will not be accessible without the "access protected menu example" permission to current user.'),
        ];
    }
    
    /**
     * Demonstrates the use of custom access check in routes.
     *
     * @throws \InvalidArgumentException
     *
     * @see \Drupal\menu_example\Controller\MenuExampleController::customAccessPage()
     */
    public function customAccess() {
        $url = Url::fromRoute('examples.menu_example.custom_access_page');
        return [
            '#markup' => $this->t('A menu item that requires the user to posess a role of "authenticated" is at @link', [
                '@link' => Link::createFromRoute($url->getInternalPath(), $url->getRouteName())
                    ->toString(),
            ]),
        ];
    }
    
    /**
     * Content will be displayed only if access check is satisfied.
     *
     * @see \Drupal\menu_example\Controller\MenuExampleController::customAccess()
     */
    public function customAccessPage() {
        return [
            '#markup' => $this->t('This menu entry will not be visible and access will result
        in a 403 error unless the user has the "authenticated" role. This is
        accomplished with a custom access check plugin.'),
        ];
    }
    
    /**
     * Give the user a link to the route-only page.
     *
     * @throws \InvalidArgumentException
     */
    public function routeOnly() {
        $url = Url::fromRoute('examples.menu_example.route_only.callback');
        return [
            '#markup' => $this->t('A menu entry with no menu link is at @link', [
                '@link' => Link::createFromRoute($url->getInternalPath(), $url->getRouteName())
                    ->toString(),
            ]),
        ];
    }
    
    /**
     * Such callbacks can be user for creating web services in Drupal 8.
     */
    public function routeOnlyCallback() {
        return [
            '#markup' => $this->t('The route entry has no corresponding menu links entry, so it provides a route without a menu link, but it is the same in every other way to the simplest example.'),
        ];
    }
    
    /**
     * Uses the path and title to determine the page content.
     *
     * This controller is mapped dynamically based on the 'route_callbacks:' key
     * in the routing YAML file.
     *
     * @param string $path
     *   Path/URL of menu item.
     * @param string $title
     *   Title of menu item.
     *
     * @return array
     *   Controller response.
     *
     * @see Drupal\menu_example\Routing\MenuExampleDynamicRoutes
     */
    public function tabsPage($path, $title) {
        $secondary = substr_count($path, '/') > 2 ? 'secondary ' : '';
        return [
            '#markup' => $this->t('This is the @secondary tab "@tabname" in the "basic tabs" example.', [
                '@secondary' => $secondary,
                '@tabname' => $title,
            ]),
        ];
    }
    
    /**
     * Demonstrates use of optional URL arguments in for menu item.
     *
     * @param string $arg1
     *   First argument of URL.
     * @param string $arg2
     *   Second argument of URL.
     *
     * @return array
     *   Controller response.
     *
     * @see https://www.drupal.org/docs/8/api/routing-system/parameters-in-routes
     */
    public function urlArgument($arg1, $arg2) {
        // Perpare URL for single arguments.
        $url_single = Url::fromRoute('examples.menu_example.use_url_arguments', [
            'arg1' => 'one',
        ]);
        // Prepare URL for multiple arguments.
        $url_double = Url::fromRoute('examples.menu_example.use_url_arguments', [
            'arg1' => 'one',
            'arg2' => 'two',
        ]);
        // Add these argument links to the page content.
        $markup = $this->t('This page demonstrates using arguments in the url. For example, access it with @link_single for single argument or @link_double for two arguments in URL', [
            '@link_single' => Link::createFromRoute($url_single->getInternalPath(), $url_single->getRouteName(), $url_single->getRouteParameters())
                ->toString(),
            '@link_double' => Link::createFromRoute($url_double->getInternalPath(), $url_double->getRouteName(), $url_double->getRouteParameters())
                ->toString(),
        ]);
        // Process the arguments if they're provided.
        if (!empty($arg1)) {
            $markup .= '<div>' . $this->t('Argument 1 = @arg', [
                '@arg' => $arg1,
            ]) . '</div>';
        }
        if (!empty($arg2)) {
            $markup .= '<div>' . $this->t('Argument 2 = @arg', [
                '@arg' => $arg2,
            ]) . '</div>';
        }
        // Finally return the markup.
        return [
            '#markup' => $markup,
        ];
    }
    
    /**
     * Demonstrate generation of dynamic creation of page title.
     *
     * @see \Drupal\menu_example\Controller\MenuExampleController::backTitle()
     */
    public function titleCallbackContent() {
        return [
            '#markup' => $this->t('The title of this page is dynamically changed by the title callback for this route defined in menu_example.routing.yml.'),
        ];
    }
    
    /**
     * Generates title dynamically.
     *
     * @see \Drupal\menu_example\Controller\MenuExampleController::titleCallback()
     */
    public function titleCallback() {
        return [
            '#markup' => $this->t('The new title is your username: @name', [
                '@name' => $this->currentUser()
                    ->getDisplayName(),
            ]),
        ];
    }
    
    /**
     * Demonstrates how you can provide a placeholder url arguments.
     *
     * @throws \InvalidArgumentException
     *
     * @see \Drupal\menu_example\Controller\MenuExampleController::placeholderArgsDisplay()
     * @see https://www.drupal.org/docs/8/api/routing-system/using-parameters-in-routes
     */
    public function placeholderArgs() {
        $url = Url::fromRoute('examples.menu_example.placeholder_argument.display', [
            'arg' => 3343,
        ]);
        return [
            '#markup' => $this->t('Demonstrate placeholders by visiting @link', [
                '@link' => Link::createFromRoute($url->getInternalPath(), $url->getRouteName(), $url->getRouteParameters())
                    ->toString(),
            ]),
        ];
    }
    
    /**
     * Displays placeholder argument supplied in URL.
     *
     * @param int $arg
     *   URL argument.
     *
     * @return array
     *   URL argument.
     *
     * @see \Drupal\menu_example\Controller\MenuExampleController::placeholderArgs()
     */
    public function placeholderArgsDisplay($arg) {
        return [
            '#markup' => $arg,
        ];
    }
    
    /**
     * Demonstrate how one can alter the existing routes.
     */
    public function pathOverride() {
        return [
            '#markup' => $this->t('This menu item was created strictly to allow the RouteSubscriber class to have something to operate on. menu_example.routing.yml defined the path as examples/menu-example/menu-original-path. The alterRoutes() changes it to /examples/menu-example/menu-altered-path. You can try navigating to both paths and see what happens!'),
        ];
    }

}