How to resolve my warning in my custom service?

Question

I am getting the following error:

Warning: Missing argument 1 for Drupal\custom_forms\Service\CustomFormsService::__construct(), called in /drupal/docroot/core/lib/Drupal/Component/DependencyInjection/Container.php on line 264 and defined in Drupal\custom_forms\Service\CustomFormsService->__construct() (line 13 of modules/custom_forms/src/Service/CustomFormsService.php).

And my code (service.php) is:

public function __construct($request) {
$this->cityname = \Drupal::request()->get('cityname');

if($this->cityname != ''){
  $result = \Drupal::database()->select('city_municipality','cm')
    ->fields('cm',array('municipality'))
    ->condition('city', $this->cityname)
    ->execute()->fetchAll();
    $result = json_encode($result);
    print $result; 
    exit;
 }

custom_forms_services.yml

  services:
       custom_forms.custom_forms_service:
           class: Drupal\custom_forms\Service\CustomFormsService

But the form functionalities are working fine.

Can anyone help me out on this?

Answer 1

You need to add an argument to your services.yml for the class to be injected:

services:
  custom_forms.custom_forms_service:
    class: Drupal\custom_forms\Service\CustomFormsService
    arguments:
      - @request_stack

Note that you should make a few changes to your service as well:

First, add an type hint for the argument:

public function __construct(\Symfony\Component\HttpFoundation\RequestStack $requestStack) {

Next, you will use the $requestStack instead of Drupal::request():

$this->cityname = $requestStack->getCurrentRequest()->query->get('cityname');