1

I want to get a list of nodes and return them as JSON along with their tags (names included). After a lot of research, I've only come up with this solution:

I have an array of Nodes (\Drupal\Core\Entity\EntityInterface) loaded with Node::loadMultiple().

Iterating over the array of nodes, and getting their tags using $node->field_tags (or whatever the machine name of the tags is) which yields an array of \Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem

Getting all the terms of the node using Term::loadMultiple() and then iterating over them and getting the name using $term->name[0]->value.

The problem is that there's an extra database read for every node, and I guess that the underlying query for this read is a JOIN :|.

Question: Is there an efficient way to load the tag (term) names along with target_id, target_type, target_uuid, etc? If no, is the current loop on each node the way to go???

More Info:

  • I'm paginating the results
  • The client can set the number of results per page, but there's a 50 nodes per page limit

Thanks

P.S.: I have two more types of tags so I have to do this two more times. Bright side is, the other two tags are 1to1.

  • 1
    You don't need Term::loadMultiple(), because you get the same result by applying referencedEntities() on the reference field. But this doesn't make a difference performance wise. For this the main tool in D8 is caching. Either in a cacheable response (add the cache tags of the nodes/terms and the node list tag to it) or if you have a lot of variations in the lists of nodes, then cache single nodes incl. the retrieved tags. – 4k4 Nov 26 '17 at 19:39
3

If you're already looping over an array of nodes, have you considered collecting the term IDs before loading them in one query? That should save a lot of the overhead of running multiple queries:

$map = [];
$tids = [];

// Collect IDs for each node:
/** @var \Drupal\node\Entity\NodeInterface[] $nodes */
foreach ($nodes as $nid => $node) {
  /** @var \Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem $item */
  foreach ($node->field_tags as $item) {
    $tid = $item->target_id;
    $map[$nid][$tid] = $tid;
    $tids[$tid] = $tid;
  }
}

// Load terms and collect their labels:
$term_labels = [];
/** @var \Drupal\taxonomy\Entity\TermInterface $term */
foreach (Term::loadMultiple($tids) as $tid => $term) {
  $term_labels[$tid] = $term->label();
}

// Assign the term labels to each node.
foreach ($map as $nid => $node_tids) {
  foreach ($node_tids as $tid) {
    $map[$nid][$tid] = $term_labels[$tid];
  }
}
  • The obvious thing is that this is far better than what I'm doing right now, so thanks. Although I can't help but wonder if it's possible to just load the name field along with the nodes. – Milad.Nozari Nov 26 '17 at 18:05
  • No, it is not. But those loaded terms will be cached after you load them the first time – Berdir Nov 27 '17 at 12:37

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