Reduce event importer invalidation

docroot/profiles/custom/sul_profile/config/sync/config_ignore.settings.yml

@@ -2,11 +2,11 @@ _core:
   default_config_hash: v7E8C8wJWeAW2BGohMNY1tZSBc4bexM6O62tGxecTfE
 mode: simple
 ignored_config_entities:
+  - 'build_hooks.frontend_environment.*'
   - 'google_tag.container.*'
   - 'next.next_entity_type_config.*'
   - 'next.next_site.*'
   - 'system.action.user_add_role_action.custm_*'
   - 'system.action.user_remove_role_action.custm_*'
   - 'user.role.custm_*'
-  - 'build_hooks.frontend_environment.*'
 enable_export_filtering: false

docroot/profiles/custom/sul_profile/config/sync/migrate_plus.migration.stanford_localist_importer.yml

@@ -18,7 +18,7 @@ source:
   request_options:
     timeout: 60
   urls: {  }
-  data_parser_plugin: localist_json
+  data_parser_plugin: sul_localist_json
   item_selector: events
   orphan_action: forget
   fields:

docroot/profiles/custom/sul_profile/modules/sul_helper/src/Plugin/migrate_plus/data_parser/SulLocalistJson.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Drupal\sul_helper\Plugin\migrate_plus\data_parser;
+
+use Drupal\stanford_migrate\Plugin\migrate_plus\data_parser\LocalistJson;
+
+/**
+ * Obtain JSON data for migration.
+ *
+ * @DataParser(
+ *   id = "sul_localist_json",
+ *   title = @Translation("SUL Localist JSON")
+ * )
+ */
+class SulLocalistJson extends LocalistJson {
+
+  protected function getSourceData(string $url): array {
+    $source_data = parent::getSourceData($url);
+
+    $event_ids = [];
+    foreach ($source_data as $key => $item) {
+      if (in_array($item['event']['id'], $event_ids)) {
+        unset($source_data[$key]);
+        continue;
+      }
+      $event_ids[] = $item['event']['id'];
+    }
+    return array_values($source_data);
+  }
+
+}