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Validators

Conditional Validator

Laminas\Validator\Conditional allows you to validate a value conditionally depending on the outcome of a user-defined rule.

Supported options

The following options are supported for Laminas\Validator\Conditional:

  • rule: A callable that will determine whether validation should execute on the value or not
  • validators: A list of validator specifications used to create a validator chain

About the $context parameter of validators

Typically, laminas-validator is used via laminas-inputfilter which is often, in turn, used via laminas-form. Some validators accept a second parameter to the isValid() method that contains the entire payload in an unfiltered and un-validated state. This parameter $context is normally the entire $_POST payload.

laminas-inputfilter always passes this parameter to the isValid method, but, because it is not part of the ValidatorInterface contract, it's documentation has often been overlooked.

Basic usage

The Conditional validator makes use of the $context parameter to determine whether validation should execute on the given value.

As such, the rule parameter must be a callable that accepts the $context array and returns a boolean to indicate whether validation should proceed.

If the rule returns false, the validator will return true, passing validation regardless of the input value. When the rule returns true, validation proceeds and returns either a successful or unsuccessful result depending on the input.

The Conditional validator must create validation chains from the given validators option, therefore it requires the ValidatorChainFactory as a constructor dependency.

Normally, using validators via laminas-inputfilter or laminas-form, this will not be a concern, but in standalone usage as documented here, we must account for this requirement.

In the following example, we only wish to validate the email address if the subscribe field evaluates to a truthy value:

use Laminas\ServiceManager\ServiceManager;
use Laminas\Validator\Conditional;
use Laminas\Validator\EmailAddress;
use Laminas\Validator\ValidatorChainFactory;
use Laminas\Validator\ValidatorPluginManager;

// The chain factory would typically be retrieved from a DI container,
// but instantiated directly here for brevity.
$chainFactory = new ValidatorChainFactory(
    new ValidatorPluginManager(
        new ServiceManager(),
    ),
);

$validator = new Conditional($chainFactory, [
    'rule' => static function (array $context): bool {
        return (bool) ($context['subscribe'] ?? null) === true;
    },
    'validators' => [
        ['name' => EmailAddress::class],
    ],
]);

$postPayload = [
    'subscribe' => '1',
    'email' => 'kermit@example.com',
];

$validator->isValid($postPayload['email'], $postPayload); // true

The rule option can be any callable, providing it has the signature callable(array): bool.

The validators option can contain as many validators as required. For more information on the shape of the validators option, consult the documentation on the ValidatorChainFactory