Validators 

Localization of client side validation 

Display of validation messages is browser-specific and not generated by TYPO3 so these messages cannot easily be changed. However, you can use JavaScript to change validation messages. See Stack Overflow for more information.

Alphanumeric validator (Alphanumeric) 

The "Alphanumeric validator" checks for alphanumeric strings. Alphanumeric is defined as a combination of alphabetic and numeric characters [A-Z + 0-9].

Number of submitted values validator (Count) 

The "Number of submitted values validator" checks if a value contains a specific number of elements. The validator has two options:

• Minimum [ options.minimum ]: The minimum count to accept.
• Maximum [ options.maximum ]: The maximum count to accept.

Use the Count validator with FileUpload and ImageUpload elements to limit the number of uploaded files. The element property multiple must be enabled.

Date range validator (DateRange) 

The "Date range validator" checks if a value is a valid DateTime object and within a specified date range. The range can be defined by providing a minimum and/or maximum date. The validator has two options:

• Format [ options.format ]: The format of the absolute minimum and maximum dates. Default: [ Y-m-d ].
• Minimum date [ options.minimum ]: The minimum date. Use an absolute date in the format Y-m-d or a relative date expression.
• Maximum date [ options.maximum ]: The maximum date. Use an absolute date in the format Y-m-d or a relative date expression.

Absolute dates use the format 'Y-m-d', which represents the RFC 3339 'full-date' format.

Relative date expressions follow the syntax of the PHP function strtotime(), for example today, tomorrow, -18 years, or +1 month. They are evaluated when the form is validated. You can mix absolute and relative dates.

The following example accepts only dates of birth at least 18 years in the past:

type: Date
identifier: date-of-birth
label: 'Date of birth'
validators:
  -
    identifier: DateRange
    options:
      minimum: '1900-01-01'
      maximum: '-18 years'

The HTML attributes min and max of the rendered date input can also contain relative date expressions. They are resolved to absolute Y-m-d dates when the form is rendered.

The input must be a DateTime object. This input can be tested against a minimum date and a maximum date. The minimum date and the maximum date are strings. The minimum and maximum date can be configured through the validator options.

Date/time validator (DateTime) 

The "Date/time validator" checks if a value is a valid DateTime object. The date string is expected to be formatted according to the W3C standard which is YYYY-MM-DDT##:##:##+##:##, for example 2005-08-15T15:52:01+00:00.

Email validator (EmailAddress) 

The "Email validator" checks if a value is a valid email address. The format of a valid email address is defined in RFC 3696. This standard allows international characters and multiple @ signs.

File size validator (FileSize) 

The "File size validator" validates the size of a file resource. The validator has two options:

• Minimum [ options.minimum ]: The minimum file size. Use the format <size>B|K|M|G. For example: 10M is 10 Megabytes.
• Maximum [ options.maximum ]: The maximum file size. Use the format <size>B|K|M|G. For example: 10M is 10 Megabytes.

Use the format <size>B|K|M|G for file size, for example, 10M is 10 megabytes. Note: the maximum file size also depends on the php.ini settings of your environment.

Floating-point number validator (Float) 

The "Floating-point number validator" checks if a value is of type float or a string matching the regular expression [0-9.e+-].

Integer number validator (Integer) 

The "Integer number validator" checks if a value is a valid integer.

Empty validator (NotEmpty) 

The "Empty validator" checks if a value is not empty (i.e. equal to NULL, empty string, empty array or empty object).

Number validator (Number) 

The "Number validator" checks if a value is a number.

Number range validator (NumberRange) 

The "Number range validator" checks if a value is a number in a specified range. The validator has two options:

• Minimum [ options.minimum ]: The minimum value.
• Maximum [ options.maximum ]: The maximum value.

Regular expression validator (RegularExpression) 

The "Regular expression validator" checks if a value matches a specified regular expression. Delimiters or modifiers are not supported. The validator has one option:

• Regular expression [ options.regularExpression ]: The regular expression to use for validation, used as given.

As an example, a user submits a domain name and the submitted value should only contain the second and the top level domain, i.e. "typo3.org" instead of "https://typo3.org". The regular expression for this would be /^[-a-z0-9]+.[a-z]{2,6}$/.

String length validator (StringLength) 

The "String length validator" checks if a value is a valid string and its length is within a specified range. The validator has two options:

• Minimum [ options.minimum ]: The minimum length of a valid string.
• Maximum [ options.maximum ]: The maximum length of a valid string.

Non-XML text validator (Text) 

The "Non-XML text validator" checks if a value is a valid piece of text (containing no XML tags). This basically means that tags are stripped out. In this special case quotes are not encoded (see filter_var() for more information.

Be aware that the value of this check entirely depends on the output context. The validated text is not expected to be secure. If you want to be sure of that, use a customized regular expression or filter on output.

Validating multi-value fields 

Some form elements submit several values as an ObjectStorage , for example a FileUpload element with multiple enabled. By default, a validator receives the whole ObjectStorage . Use this for validators that check the collection as a whole, such as the Count validator.

If a validator checks single items, implement the marker interface ObjectStorageElementValidatorInterface . The validator is then called once for each item. The validators MimeTypeValidator and FileSizeValidator work this way.

use TYPO3\CMS\Extbase\Validation\Validator\AbstractValidator;
use TYPO3\CMS\Form\Mvc\Validation\ObjectStorageElementValidatorInterface;

final class CustomFileValidator extends AbstractValidator implements
  ObjectStorageElementValidatorInterface
{
  public function isValid(mixed $value): void
  {
    // $value is a single item of the ObjectStorage,
    // for example a FileReference
  }
}

For values that are not an ObjectStorage , the interface has no effect.