Drupal 9 Views custom filter plugin to filter content based on users zipcode

mymodule.module

<?php

/**
 * @file
 * Contains mymodule.module.
 */

use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function mymodule_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the mymodule module.
    case 'help.page.mymodule':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('This module used for custom work of personalization in the site.') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_views_data().
 */
function mymodule_views_data() {
  $data = [];

  // Register the node__field_event_location table.
  $data['node__field_event_location'] = [
    'table' => [
      'group' => t('Personalization'),
      'join' => [
        // Join with the node table.
        'left_field' => 'entity_id',
        'field' => 'entity_id',
        'table' => 'node_field_data',
      ],
    ],
    'nearest_event' => [
      'title' => t('Nearest Events - Personalization'),
      'help' => t("Filter events based on the user\'s zipcode and nearest event rules."),
      'filter' => [
        'field' => 'id',
        'id' => 'mymodule_nearest_event_filter',
      ],
    ],
  ];

  return $data;
}

NearestEventFilter.php

<?php

namespace Drupal\mymodule\Plugin\views\filter;

use Drupal\views\Plugin\views\filter\FilterPluginBase;
use Drupal\Core\Form\FormStateInterface;
use Geocoder\Formatter\StringFormatter;
use Drupal\user\Entity\User;

/**
 * Filter handler to display nearest events based on user's zipcode.
 *
 * @ingroup views_filter_handlers
 *
 * @ViewsFilter("mymodule_nearest_event_filter")
 */
class NearestEventFilter extends FilterPluginBase {

  /**
   * {@inheritdoc}
   */
  public function adminSummary() {
    // Show summary based on the options chosen.
    $summary = $this->operator . ' ';
    $options = [];
    if ($this->options['nearest_events']['city']) {
      $options[] = $this->t('City');
    }
    if ($this->options['nearest_events']['state']) {
      $options[] = $this->t('State');
    }
    if ($this->options['nearest_events']['country']) {
      $options[] = $this->t('Country');
    }
    $summary .= implode(', ', $options);
    return $summary;
  }

  /**
   * {@inheritdoc}
   */
  public function defineOptions() {
    $options = parent::defineOptions();

    // Option 1: Checkboxes to choose which nearest event options to show.
    $options['nearest_events']['city'] = FALSE;
    $options['nearest_events']['state'] = FALSE;
    $options['nearest_events']['country'] = FALSE;

    return $options;
  }

  /**
   * {@inheritdoc}
   */
  public function buildOptionsForm(&$form, FormStateInterface $form_state) {
    parent::buildOptionsForm($form, $form_state);

    // Implement the checkboxes for the nearest event options.
    $form['nearest_events'] = [
      '#type' => 'fieldset',
      '#title' => $this->t('Nearest event options'),
      '#collapsible' => TRUE,
      '#collapsed' => FALSE,
    ];

    $form['nearest_events']['city'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('City'),
      '#default_value' => $this->options['nearest_events']['city'],
    ];

    $form['nearest_events']['state'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('State'),
      '#default_value' => $this->options['nearest_events']['state'],
    ];

    $form['nearest_events']['country'] = [
      '#type' => 'checkbox',
      '#title' => $this->t('Country'),
      '#default_value' => $this->options['nearest_events']['country'],
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function query() {
    // Retrieve the current logged-in user's zipcode from the user entity field.
    $user = \Drupal::currentUser();
    // Load the user entity.
    $user = User::load($user->id());
    $zipcode = $user->get('field_zipcode')->value;

    // If user's zipcode is empty then add condition event bundle = NOEVENT so
    // that no events are shown and it fllback to NO RESULTS BEHAVIOR. @See NO
    // RESULTS BEHAVIOR in the view.
    if (empty($zipcode)) {
      $this->addNoEventCondition();
    }

    // If user's zipcode is not empty, then get the user's city, state, and
    // country.
    // Use the Geocoder module to get the user's city, state, and country.
    // Replace 'googlemaps' with the appropriate Geocoder provider ID.
    $geocoder = \Drupal::service('geocoder');
    /** @var Geocoder\Model\AddressCollection */
    $result = $geocoder->geocode($zipcode, ['googlemaps']);
    /** @var Geocoder\Provider\GoogleMaps\Model\GoogleAddress */

    // If no results are found, then add condition event type = NOEVENT so
    // that no events are shown and it fllback to NO RESULTS BEHAVIOR. @See NO
    // RESULTS BEHAVIOR in the view.
    if (empty($result)) {
      $this->addNoEventCondition();
    }

    // Get the user's city, state, and country.
    $location = $result->first();
    $city = $location->getLocality();
    $formatter = new StringFormatter();
    $state = $formatter->format($location, '%a1');
    $country = $location->getCountry()->getCode();

    // Build the query to filter events based on the nearest event rules.
    $this->ensureMyTable();

    $or_conditions = [];
    // If the user's city is not empty, then add the city condition to the
    // query.
    if (!empty($city) && $this->options['nearest_events']['city']) {
      $or_conditions[] = "$this->tableAlias.field_event_location_locality = '$city'";
    }
    // If the user's state is not empty, then add the state condition to the
    // query.
    if (!empty($state) && $this->options['nearest_events']['state']) {
      $or_conditions[] = "$this->tableAlias.field_event_location_administrative_area = '$state'";
    }
    // If the user's country is not empty, then add the country condition to the
    // query.
    if (!empty($country) && $this->options['nearest_events']['country']) {
      $or_conditions[] = "$this->tableAlias.field_event_location_country_code = '$country'";
    }

    // Add the OR conditions to the query.
    if (!empty($or_conditions)) {
      $this->query->addWhereExpression($this->options['group'], implode(' OR ', $or_conditions));
    }
  }

  /**
   * Add condition event bundle = NOEVENT so that no events are shown and it.
   */
  protected function addNoEventCondition() {
    $this->ensureMyTable();
    $this->query->addWhere($this->options['group'], "$this->tableAlias.bundle", 'NOEVENT', '=');
  }

}