local_weather_forecast.install

<?php

use Drupal\taxonomy\Entity\Term;
use \Drupal\node\Entity\Node;

function local_weather_forecast_install() {
  // Install some example cities so that we can demo functionality.
  $vocab = 'city';
  if($city_vocab = \Drupal\taxonomy\Entity\Vocabulary::load($vocab)) {
    $module_handler = \Drupal::service('module_handler');
    $module_path = $module_handler->getModule('local_weather_forecast')->getPath();
    // Cities are stored in the city_data directory of this module
    $csv_uri = $module_path . '/city_data/cities.csv';
    // Open the file for reading
    if (($h = fopen("{$csv_uri}", "r")) !== FALSE)
    {
      // Each line in the file is converted into an individual array that we call $data
      while (($data = fgetcsv($h, 1000, ",")) !== FALSE)
      {
        $cities[] = $data[0];
      }
      fclose($h);
    }
    // Programatically create taxonomy terms in the city vocabulary.
    foreach ($cities as $city) {
      $term = Term::create(array(
        'parent' => array(),
        'name' => $city,
        'vid' => $vocab,
        'uid' => 1,
      ))->save();
    }
  }

  // Find the tid of the 'Des Moines' term created above
  $term = \Drupal::entityQuery('taxonomy_term')
    ->condition('name', 'Des Moines')
    ->execute();
  if(!empty($term)) {
    $tid = reset($term);
    // Create an example node for Des Moines
    $node = Node::create([
      'type' => 'city_profile',
      'title' => 'Des Moines',
      'field_city' => [
        'target_id' => $tid,
      ],
    ]);
    $node->save();
  }
}

/**
 * Implements hook_uninstall().
 */
function local_weather_forecast_uninstall() {
  // Load all city term entities
  $tids = \Drupal::entityQuery('taxonomy_term')
    ->condition('vid', 'city')
    ->execute();
  // Delete city term entities.
  if (!empty($tids)) {
    $termStorage  = \Drupal::entityTypeManager()->getStorage('taxonomy_term');
    $entities = $termStorage->loadMultiple($tids);
    $termStorage->delete($entities);
  }
  // Load all city profile node entities
  $nids = \Drupal::entityQuery('node')
    ->condition('type', 'city_profile')
    ->execute();
  // Delete city profile entities.
  if (!empty($nids)) {
    $nodeStorage  = \Drupal::entityTypeManager()->getStorage('node');
    $entities = $nodeStorage->loadMultiple($nids);
    $nodeStorage->delete($entities);
  }
  $config_factory = Drupal::configFactory();
  // Delete city profile fields
  $config_factory->getEditable('core.base_field_override.node.city_profile.title')->delete();
  $config_factory->getEditable('core.entity_form_display.node.city_profile.default')->delete();
  $config_factory->getEditable('core.entity_view_display.node.city_profile.default')->delete();
  $config_factory->getEditable('core.entity_view_display.node.city_profile.teaser')->delete();
  $config_factory->getEditable('field.field.node.city_profile.body')->delete();
  $config_factory->getEditable('field.field.node.city_profile.field_city')->delete();
  $config_factory->getEditable('field.storage.node.field_city')->delete();
  $config_factory->getEditable('local_weather_forecast')->delete();
  $config_factory->getEditable('node.type.city_profile')->delete();
  $config_factory->getEditable('taxonomy.vocabulary.city')->delete();
}