Has anyone gotten custom constraints working in drupal 8?

By matthias_bauw on 28 Sep 2015 at 18:55 UTC

Seems like a great feature to do validation on an entity level. But strangely enough I can't track down relevant documentation on this. I tried to build a custom constraint.

I used an annotation like this

/**
 * @Constraint(
 *  id = "SubscriptionExists",
 *  label = @Translation("Is Subscription Unique", context = "Validation"),
 *  type = { "string", },
 * )
 */

and then I used a SubscriptionExists class that extends class and I created a SubscriptionExistsValidator class

Then I adapted by Entity annotation adding the constraint there:
* constraints = {
* "SubscriptionExists" = {},
* },

But that is where it goes wrong. I keep getting the error
Drupal\Component\Plugin\Exception\PluginNotFoundException: The "SubscriptionExists" plugin does not exist. in Drupal\Core\Plugin\DefaultPluginManager->doGetDefinition() (line 57 of core/lib/Drupal/Component/Plugin/Discovery/DiscoveryTrait.php).

So I think the plugin is not detected. But I can't figure out why. I know I'm not giving much info on this one but I can't really tell where to start. I have put the files in my /modules/custom/modulename/src/plugins directory. Maybe it's like the entity api and I need to put the code in a certain directoryname to make them being detected.

Can somebody offer me some tips or tell me where I can find reference?

Thanks a lot

Matt.

Comments

Bingo!

matthias_bauw commented 29 September 2015 at 05:53

Well...

Finally fixed it. I solved it by looking at the user entity definition and I have a few remarks that might come in handy:

Use the @Constraint annotation like I used ablove
There is no need to use the Constraint parameter in the entity annotation, seems like a wrong thing in docs
Put your constraint in /modules/custom/modulename/Plugin/Validator/Constraint. I couldn't get it to work in any other way

Please note that the path to

markwittens commented 29 May 2016 at 17:27

Please note that the path to put the constraint in should be /modules/custom/modulename/src/Plugin/Validator/Constraint

How did you make it work?

acidaniel commented 24 May 2017 at 03:55

HI, Im working with a custom field adding a custom unique validation, but I always get an error:

Drupal\Component\Plugin\Exception\PluginException: Plugin (api_documentation) instance class "Drupal\cl_test_rest_sphinx\Plugin\Validation\Constraint\ApiDocumentation" does not exist. in Drupal\Component\Plugin\Factory\DefaultFactory::getPluginClass() (line 97 of core/lib/Drupal/Component/Plugin/Factory/DefaultFactory.php).

I have in my custom module in the .module file:

<?php

/**
 * Implements hook_entity_bundle_field_info_alter().
 */
function cl_test_rest_sphinx_entity_bundle_field_info_alter(&$fields, \Drupal\Core\Entity\EntityTypeInterface $entity_type, $bundle) {
  if ($bundle === 'documentation') {
    if (isset($fields['field_machine_name'])) {
      $fields['field_machine_name']->addConstraint('api_documentation', []);
    }
  }
}

In the src/Plugin/Validation/Constraint/ApiDocumentation.php file:

<?php

namespace Drupal\cl_test_rest_sphinx\Plugin\Validaton\Constraint;

use Drupal\Core\Validation\Plugin\Validation\Constraint\UniqueFieldConstraint;
use Symfony\Component\Validator\Constraint;

/**
 * Prevent duplicated values on machine_name field.
 *
 * @Constraint(
 *   id = "api_documentation",
 *   label = @Translation("Unique Machine Name", context = "Validation"),
 * )
 */
//Here I tried to extend to Constraint and to UniqueFieldConstraint with same error.
class ApiDocumentation extends UniqueFieldConstraint  {
  public $message = 'The machine name for documentation %value already exist';
}

And in my In the src/Plugin/Validation/Constraint/ApiDocumentationValidator.php file:

<?php

namespace Drupal\cl_test_rest_sphinx\Plugin\Validaton\Constraint;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

class ApiDocumentationValidator extends ConstraintValidator {

  /**
   * {@inheritdoc}
   */
  public function validate($items, Constraint $constraint) {
    return $this->context->addViolation($constraint->message, array('%label' => 'test', '%value' => 'test'));

  }
}

I expect to see the message when I save the node of type documentation but instead I get the error above, any clue? Also I tried to change the annotation as you suggestion but the same.

Any help will be very appreciated.