CacheTag Inject module for Drupal

cachetag_inject.info.yml

name: 'CacheTag Inject'
type: module
description: 'Allows developers to edit an array of Node IDs or URI paths to assign specific CacheTags.'
core_version_requirement: ^10
package: Custom
dependencies:
  - drupal:node

cachetag_inject.module

<?php

use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function cachetag_inject_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.cachetag_inject':
      return '<p>' . t('Allows developers to edit an array of Node IDs or URI paths to assign specific CacheTags.') . '</p>';
  }
}

/**
 * Implements hook_page_attachments_alter().
 */
function cachetag_inject_page_attachments_alter(array &$attachments) {
  // Array of Node IDs or URI paths to assign specific CacheTags.
  $items_to_cache = [
    // Example Node IDs.
    'node/1',
    'node/2',
    // Example URI paths.
    'some/custom/path',
  ];

  // Define the cache tags you want to inject.
  $cache_tags = [
    'custom_tag_1',
    'custom_tag_2',
  ];

  // Get the current path.
  $current_path = \Drupal::service('path.current')->getPath();
  $current_path_alias = \Drupal::service('path_alias.manager')->getAliasByPath($current_path);

  // Check if the current path or its alias is in the list.
  if (in_array($current_path, $items_to_cache) || in_array($current_path_alias, $items_to_cache)) {
    $cache_metadata = new CacheableMetadata();
    $cache_metadata->setCacheTags($cache_tags);
    $cache_metadata->applyTo($attachments['#cache']);
  }
}