Validation

Why is validation needed?

People often assume that domain objects are consistent and adhere to some rules at all times.

Unfortunately, this is not achieved automatically. So it is important to define such rules explicitly.

In the blog example for the model Person the following rules can be defined

• First name and last name should each have no more then 80 chars.
• A last name should have at least 2 chars.
• The parameter email has to contain a valid email address.

These rules are called invariants, because they must be valid during the entire lifetime of the object.

At the beginning of your project, it is important to consider which invariants your domain objects will consist of.

When does validation take place?

Domain objects in Extbase are validated only at one point in time: When they are used as parameter in a controller action.

When a user sends a request, Extbase first determines which action within the controller is responsible for this request.

Extbase then maps the arguments so that they fit types as defined in the actions method signature.

If there are validators defined for the action these are applied before the actual action method is called.

When the validation fails the method errorAction() of the current controller is called.

Validation of model properties

You can define simple validation rules in the domain model by the annotation Validate.

Example:

use TYPO3\CMS\Extbase\Annotation\Validate;

class Blog extends AbstractEntity
{
    /**
     * A short description of the blog
     *
     * @Validate("StringLength", options={"maximum": 150})
     */
    public string $description = '';
}

In this code section the validator StringLength provided by Extbase in class \TYPO3\CMS\Extbase\Validation\Validator\StringLengthValidator is applied with one argument.

Validation of controller arguments

The following rules validate each controller argument:

• If the argument is a domain object, the annotations @TYPO3\CMS\Extbase\Annotation\Validate in the domain object are taken into account.
• If there is set an annotation @TYPO3\CMS\Extbase\Annotation\IgnoreValidation for the argument, no validation is done.
• Validators added in the annotation of the action are applied.

If the arguments of an action are invalid, the errorAction is executed. By default a HTTP response with status 400 is returned. If possible the user is forwarded to the previous action. This behaviour can be overridden in the controller.

Annotations with arguments

Annotations can be called with zero, one or more arguments. See the following examples:

use TYPO3\CMS\Extbase\Annotation\Validate;

class Person extends AbstractEntity
{
    /**
     * @Validate("EmailAddress")
     */
    protected string $email = '';

    /**
     * @Validate("StringLength", options={"maximum": 80})
     */
    protected string $firstname = '';

    /**
     * @Validate("StringLength", options={"minimum": 2, "maximum": 80})
     */
    protected string $lastname = '';
}

Available validators shipped with Extbase can be found within EXT:extbase/Classes/Validation/Validator/.

Manually call a validator

It is possible to call a validator in your own code with the method \TYPO3\CMS\Extbase\Validation\ValidatorResolver::createValidator().

However please note that the class ValidatorResolver is marked as @internal and it is therefore not advisable to use it.