A site maintainer can bulk delete all terms in a vocabulary that are referenced by N or fewer nodes

This adds a "Prune terms" menu item and a Prune tab that allows selection of a vocabulary and 'depth' to delete terms that are unused, referenced by one node, or two, or three.

The deletion is then done in a batch process (which is based on the form batch process, which is annoying as it makes doing the drush version of this extra work, which i have not done yet).

Did a bit of refactoring of other code to make use of it here— the list page is now generated by a single query which probably possible to make it user-sortable (it is sorted by usage count and then term ID now).

Closes #3311325

src/Controller/TaxonomyList.php

@@ -2,9 +2,9 @@
 
 namespace Drupal\cleantaxonomy\Controller;
 
+use Drupal\cleantaxonomy\TermsUsageCounterInterface;
 use Drupal\Core\Link;
 use Drupal\Core\Url;
-use Drupal\Core\Database\Connection;
 use Drupal\Core\Controller\ControllerBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
@@ -12,30 +12,29 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  * Provides route responses for the cleantaxonomy module.
  */
 class TaxonomyList extends ControllerBase {
+
   /**
-   * The database service.
+   * The term usage counter service.
    *
-   * @var \Drupal\Core\Database\Connection
+   * @var \Drupal\cleantaxonomy\TermsUsageCounter
    */
-  protected $database;
+  protected $termsUsageCounter;
 
   /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container) {
     return new static(
-      $container->get('database')
+      $container->get('cleantaxonomy.terms_usage_counter')
     );
   }
 
   /**
    * Constructs a cleantaxonomy object.
    *
-   * @param \Drupal\Core\Database\Connection $database
-   *   A database connection.
    */
-  public function __construct(Connection $database) {
-    $this->database = $database;
+  public function __construct(TermsUsageCounterInterface $termsUsageCounter) {
+    $this->termsUsageCounter = $termsUsageCounter;
   }
 
   /**
@@ -45,58 +44,36 @@ class TaxonomyList extends ControllerBase {
    *   A tabular format of the terms list.
    */
   public function taxonomytermsList() {
+    $terms = $this->termsUsageCounter->getTermsWithUsage();
+    return $this::termsTable($terms);
+  }
+
+  public static function termsTable($terms) {
     $header = [
-      $this->t('Term ID'),
-      $this->t('Taxonomy Term'),
-      $this->t('Vocabulary'),
+      t('Term ID'),
+      t('Taxonomy Term'),
+      t('Vocabulary'),
       [
-        'data' => $this->t('No. of nodes attached'),
+        'data' => t('No. of nodes attached'),
         'sort' => 'desc',
       ],
       [
-        'data' => $this->t('Operation'),
+        'data' => t('Operation'),
         'colspan' => '4',
       ],
     ];
-    $id_name = $this->database->select('taxonomy_term_field_data')
-      ->fields('taxonomy_term_field_data', ['tid', 'name', 'vid'])
-      ->execute();
-    $id_name_records = $id_name->fetchAll();
-    $id_name_values = [];
-    $size = 0;
-    foreach ($id_name_records as $id_name_record) {
-      $id_name_values[$id_name_record->tid] = $id_name_record;
-      $size++;
-    }
-    $node_count = $this->database->select('taxonomy_index', 'x')
-      ->fields('x', ['tid']);
-    $node_count->addExpression('COUNT(x.nid)', 'n');
-    $node_count->groupBy('x.tid');
-    $data = $node_count->execute();
-    $node_count_records = $data->fetchAll(\PDO::FETCH_ASSOC);
-    foreach ($node_count_records as $node_count_record) {
-      $tags[$node_count_record['tid']]['count'] = $node_count_record['n'];
-    }
-    foreach ($id_name_values as $id_name_value) {
-      $tags[$id_name_value->tid]['name'] = $id_name_value->name;
-      $tags[$id_name_value->tid]['tid'] = $id_name_value->tid;
-      $tags[$id_name_value->tid]['vid'] = $id_name_value->vid;
-      if (!$tags[$id_name_value->tid]['count']) {
-        $tags[$id_name_value->tid]['count'] = '0';
-      }
-    }
     $rows = [];
-    foreach ($tags as $value) {
+    foreach ($terms as $value) {
       $rows[] = [
         'data' => [
-          $this->t('@tid', ['@tid' => $value['tid']]),
-          $this->t('@name', ['@name' => $value['name']]),
-          $this->t('@vid', ['@vid' => $value['vid']]),
-          $this->t('@count', ['@count' => $value['count']]),
-          Link::fromTextAndUrl($this->t('View'), Url::fromUri('internal:/taxonomy/term/' . $value['tid'], [$value['tid']])),
-          Link::fromTextAndUrl($this->t('Edit'), Url::fromUri('internal:/taxonomy/term/' . $value['tid'] . '/edit')),
-          Link::fromTextAndUrl($this->t('Delete'), Url::fromUri('internal:/taxonomy/term/' . $value['tid'] . '/delete')),
-          Link::fromTextAndUrl($this->t('Replace'), new Url('cleantaxonomy.replace', ['tid' => $value['tid']])),
+          t('@tid', ['@tid' => $value['tid']]),
+          t('@name', ['@name' => $value['name']]),
+          t('@vid', ['@vid' => $value['vid']]),
+          t('@count', ['@count' => $value['count']]),
+          Link::fromTextAndUrl(t('View'), Url::fromUri('internal:/taxonomy/term/' . $value['tid'], [$value['tid']])),
+          Link::fromTextAndUrl(t('Edit'), Url::fromUri('internal:/taxonomy/term/' . $value['tid'] . '/edit')),
+          Link::fromTextAndUrl(t('Delete'), Url::fromUri('internal:/taxonomy/term/' . $value['tid'] . '/delete')),
+          Link::fromTextAndUrl(t('Replace'), new Url('cleantaxonomy.replace', ['tid' => $value['tid']])),
         ],
       ];
     }
@@ -104,7 +81,7 @@ class TaxonomyList extends ControllerBase {
       '#type' => 'table',
       '#header' => $header,
       '#rows' => $rows,
-      '#empty' => $this->t('No taxonomy terms available.'),
+      '#empty' => t('No taxonomy terms available.'),
     ];
     $build['admin_cleantaxonomy_list_pager_pager'] = ['#type' => 'pager'];
     return $build;