Improve linking to md version of an entity

Thanks for the great suggestion, mxr576! I already have this implemented in a local branch of the module, though I haven’t been able to push it yet.

@Christophweber, what mxr576 is suggesting is essentially adding a new Link Template to entities marked as supported for Markdown conversion.

Here’s the official documentation on how to do it: Link Relation Types and Link Templates →

The implementation is straightforward and looks like this:

/**
 * Implements hook_entity_type_alter().
 *
 * Adds a 'markdownify' link template to supported entity types.
 */
function markdownify_entity_type_alter(array &$entity_types): void {
  /** @var \Drupal\Core\Entity\EntityTypeInterface[] $entity_types */
  $validator = \Drupal::service('markdownify.supported_entity_types.validator');

  foreach ($validator->getSupportedEntityTypes() as $entity_type_id) {
    if (!isset($entity_types[$entity_type_id])) {
      continue;
    }

    $entity_type = $entity_types[$entity_type_id];
    if (!$entity_type instanceof EntityTypeInterface) {
      continue;
    }

    // Add 'markdownify' link template based on the canonical path.
    if ($entity_type->hasLinkTemplate('canonical')) {
      $canonical_path = $entity_type->getLinkTemplate('canonical');
      $entity_type->setLinkTemplate('markdownify', $canonical_path . '.md');
    }
  }
}

The reason I haven’t pushed this contribution yet is that I’m uncertain about the name of the link template. In my implementation, I named it 'markdownify', so people can get the Markdown URL using code like this:

$markdown_url = $entity->toUrl('markdownify')->setAbsolute(TRUE)->toString();

However, in mxr576's example, the name is 'canonical-md', which means the URL would be retrieved like this:

$markdown_url = $entity->toUrl('canonical-md')->setAbsolute(TRUE)->toString();

Do you have any preferences for the naming convention? Let me know, and I’ll push a merge request with the changes.

Thanks!