Using cache tags for a particular node list

Question

Caching in Drupal 8 is great, but documentation is thin (at this time) on using cache tags for render arrays in Drupal 8.

I have some code that basically generates a list of node teasers, say for content types "books" and "magazines". I'm caching the list to speed things up. I would like to refresh the list every time a "book" or "magazine" is added/deleted/edited. So I have a render array that looks like this:

$build = array(
  '#type' => 'markup',
  '#markup' => $sMarkup,        
  '#cache' => [
    'keys' => ['home-all','home'],
    'tags'=> ['node_list'], // invalidate cache when any node content is added/changed etc.
    'max-age' => '36600', // invalidate cache after 10h
  ],
);

By using the cache tag ['node_list'], the cache invalidates properly when content is added or edited, but will also invalidate when a content type not being listed here is changed, say "casette".

What cache tags can I use to limit the invalidation to when only "book" or "magazine" is added/changed/deleted? I've tried using: ['book_list','magazine_list'] but that doesn't work.

Answer 1

Starting Drupal 8.9.0, there is a new ENTITY_TYPE_list:BUNDLE cache tag added (see the change record).

So in your case you would simply need to tag our list with node_list:book.

https://www.drupal.org/node/3107058

Answer 2

In this case I know two options.

One - Include all node tags (node:{#id}), if doesn't matter if a new node of a particular type was added.

Two - Create and control your own cache tag, and invalidade it when you want.

I'm developing a site that was needed create a term list cache per vocab_id. In this case every time that a term from a particular vocab_id change/add/delete the cache tag is invalided using Cache::invalidateTags($tag_id) then my block will be rebuild.

Edit 1

Example:

use Drupal\Core\Cache\Cache;

function filters_invalidate_vocabulary_cache_tag($vocab_id) {
  Cache::invalidateTags(array('filters_vocabulary:' . $vocab_id));
}

In your case maybe is just change $vocab_id for $node_type.

Answer 3

See the contrib module handy_cache_tags. I haven't used it (yet), but it purports to do exactly what you are looking for. From the module's description:

The module provides the following cache tags for you to use:

handy_cache_tags:[entity_type]
handy_cache_tags:[entity_type]:[entity_bundle]