Tell taxonomy links to use route in custom module

Question

I have a module where I created a route /page/tag/{term} that uses a controller for modifications to how the term page is handled.

The problem is that when any page displays these term links, they don't use the custom route, but the default /taxonomy/term/{id}.

How can I tell the taxonomy term links to use my custom route?

Adding the path as the term alias skips over the custom route entirely.

OR, how would I get rid of the custom route and create a pathauto pattern using the same path, but tell those pages to use my custom controller?

I have tried both methods without success...

---

Here is what I've tried with modifying the existing route:

modulename.services.yml

services:
  modulename.route_subscriber:
    class: Drupal\modulename\Routing\RouteSubscriber
    tags:
      - { name: event_subscriber, priority: 100 }

modulename/src/Routing/RouteSubscriber.php

namespace Drupal\modulename\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;

/**
 * Listens to the dynamic route events.
 */
class RouteSubscriber extends RouteSubscriberBase {

    /**
    * {@inheritdoc}
    */
    protected function alterRoutes(RouteCollection $collection) {
        if ($route = $collection->get('entity.taxonomy_term.canonical')) {
            // i've tried both of these
            $route->addDefaults(['_controller' => '\Drupal\modulename\Controller\ListController::list_by_tag' ']);
            $route->addDefaults(['_title' => 'test']);
        }
    }

}

---

Edit: after seeing this, I thought about keeping my custom route and using the alterRoutes to change the links...

$route->setPath('/page/tag');

That worked, but it adds on ?taxonomy_term=123

How can I get the term name into the url? /page/tag/term

---

Update:

Still can't figure out how to get the term name from the route (without loading the taxonomy entity - I'd imagine that is too much load)

Also, I will need to make sure I'm in a specific vocabulary before changing the route.

Any ideas?

Answer 1

In my case, I'm also using a RouteSubscriber to change the default controller responsible for handling taxonomy term entities. I also wanted to use a custom template only for a specific taxonomy (called my_taxonomy in the example below).

Here is the code for the RouteSubscriber:

<?php

namespace Drupal\my_module\Routing;

use Drupal\Core\Routing\RoutingEvents;
use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;

class RouteSubscriber extends RouteSubscriberBase {

    /**
     * {@inheritdoc}
     */
    protected function alterRoutes(RouteCollection $collection) {
        if ($route = $collection->get('entity.taxonomy_term.canonical')) {
            $route->setDefaults([
                '_controller' => '\Drupal\my_module\Controller\DefaultController::listAll',
            ]);
        }
    }

    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() {
        $events[RoutingEvents::ALTER] = ['onAlterRoutes', -200];
        return $events;
    }

}

And here is the code for the controller. Note that a custom render array can be returned only for terms of the specific taxonomy my_taxonomy. All other terms fall back to the default controller used by the views module in the original route:

<?php

namespace Drupal\my_module\Controller;

use Drupal\Core\Controller\ControllerBase;
use Drupal\taxonomy\Entity\Term;
use Drupal\views\Routing\ViewPageController;
use Symfony\Component\HttpFoundation\Request;

class DefaultController extends ControllerBase {

    public function listAll(Request $request) {
        $render = [];

        $tid = \Drupal::routeMatch()->getRawParameter('taxonomy_term');
        $term = Term::load($tid);
        $bundle = $term->bundle();
        if ($bundle == 'my_taxonomy') {
            // render array for your custom template
        } else {
            // falls back to the default ViewPageController to handle all other taxonomies
            $viewPageController = new ViewPageController();
            $render = $viewPageController->handle('taxonomy_term', 'page_1', \Drupal::routeMatch());
        }

        // Return render array
        return $render;
    }

}