I'm having trouble validating a value to allow NULL but not an empty string with the Symfony2 validator component.
I've integrated the component in a Silex application and used the Property Constraint target to validate some properties of my Application Entities (not a Doctrine Entity).
I've added this static method to my Entity class to validate name and service_id on my Entity, problem is that when service_id
is NULL which should be valid the NotBlank
constraint kicks in and reports a violation.
static public function loadValidatorMetadata(ClassMetadata $metadata)
{
// name should never be NULL or a blank string
$metadata->addPropertyConstraint('name', new Assert\NotNull());
$metadata->addPropertyConstraint('name', new Assert\NotBlank());
// service_id should either be a non-blank string or NULL
$metadata->addPropertyConstraint('service_id', new Assert\NotBlank());
}
Bottomline, I'm looking how to allow either a String or NULL as service_id
but not allow an empty string.
PS: I've also tried the MinLength(1)
constraint but that allows empty strings unfortunately.
The NotBlank
constraint treats null
as a blank value, as can be seen in this test.
When using doctrine, this can be solved by using the Valid constraint. If the value of the field is not null
, it will attempt to validate it.
Since you are not using doctrine entities, you'll probably have to use a callback validator or write your own constraint.
To answer your new question on adding a callback constraint as a property constraint: No, it is not possible to do that.
The callback constraint acts on the whole object, not just a single property. Here's an example of how you can use the callback constraint:
use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Mapping\ClassMetadata;
use Symfony\Component\Validator\ExecutionContext;
$app = new Silex\Application();
$app->register(new Silex\Provider\ValidatorServiceProvider());
class Person
{
public $name;
public function validateName(ExecutionContext $context)
{
if ('John Doe' === $this->name) {
$context->addViolationAtPath('name', 'Name must not be "John Doe"');
}
}
static public function loadValidatorMetadata(ClassMetadata $metadata)
{
$metadata->addConstraint(new Assert\Callback(array('validateName')));
$metadata->addPropertyConstraint('name', new Assert\NotNull());
}
}
$person = new Person();
$person->name = 'John Doe';
$violations = $app['validator']->validate($person);
var_dump('Violations for John Doe');
var_dump((string) $violations);
$person = new Person();
$violations = $app['validator']->validate($person);
var_dump('Violations for Person with name null');
var_dump((string) $violations);
$person = new Person();
$person->name = 'Igor Wiedler';
$violations = $app['validator']->validate($person);
var_dump('Violations for Igor Wiedler');
var_dump((string) $violations);