After save empty cache of referenced node

Question

I have two content types. For clearer question I will work with the content types event and location.

From my location content type I can reference to and event.

Then on the event page I show the location that is connected to this event. I do this by creating a Views Block. This views block is showing content of the type location with a contextual filter to only show content with the Content ID from url.

This works fine. But there are events that don't have a location. On these events page I have a button saying add location. I do this with the following Twig Tweak:

{% if drupal_view_result('view-name', 'location-block') is empty %}
    <a href="/node/add/location">Add location</a>
{% else %}
    {{ drupal_view('view-name', 'location-block') }}
{% endif %}

This also works. But when I am on a event page and click the add location button I can add the location. When I go back to the same event page I was before I still see the add location button. Because the page is cached.

Is there a way to empty the cache of this event page after saving the location that is refering to the event? Or is there a other way to deal with this?

I tried if the problem was in the views cache but it wasn't turning it off for the block or removing only the views cache didn't work.

Thanks in advance

Answer 1

You may specify any cache meta data directly in your Twig template. I suppose 'node_list' cache tag can help in this case.

{{ {'#cache': {'tags': ['node_list']}} }}

Another approach could be configuring views 'No results behavior' to show that link.

Answer 2

Since you're creating a reference to a location node, you'll know its node id upon saving the event.

At that point, you need to call \Drupal\Core\Cache\Cache::invalidateTags([$nid]) where $nid is the node id of the location.

There are many possibilities where this could be invoked, for example, in hook_entity_presave()