Introduction to Zend\InputFilter

The Zend\InputFilter component can be used to filter and validate generic sets of input data. For instance, you could use it to filter $_GET or $_POST values, CLI arguments, etc.

To pass input data to the InputFilter, you can use the setData() method. The data must be specified using an associative array. Below is an example on how to validate the data coming from a form using the POST method.

use Zend\InputFilter\InputFilter;
use Zend\InputFilter\Input;
use Zend\Validator;

$email = new Input('email');
$email->getValidatorChain()
      ->attach(new Validator\EmailAddress());

$password = new Input('password');
$password->getValidatorChain()
         ->attach(new Validator\StringLength(8));

$inputFilter = new InputFilter();
$inputFilter->add($email)
            ->add($password)
            ->setData($_POST);

if ($inputFilter->isValid()) {
    echo "The form is valid\n";
} else {
    echo "The form is not valid\n";
    foreach ($inputFilter->getInvalidInput() as $error) {
        print_r($error->getMessages());
    }
}

In this example we validated the email and password values. The email must be a valid address and the password must be composed with at least 8 characters. If the input data are not valid, we report the list of invalid input using the getInvalidInput() method.

You can add one or more validators to each input using the attach() method for each validator. It is also possible to specify a “validation group”, a subset of the data to be validated; this may be done using the setValidationGroup() method. You can specify the list of the input names as an array or as individual parameters.

// As individual parameters
$inputFilter->setValidationGroup('email', 'password');

// or as an array of names
$inputFilter->setValidationGroup(array('email', 'password'));

You can validate and/or filter the data using the InputFilter. To filter data, use the getFilterChain() method of individual Input instances, and attach filters to the returned filter chain. Below is an example that uses filtering without validation.

use Zend\InputFilter\Input;
use Zend\InputFilter\InputFilter;

$input = new Input('foo');
$input->getFilterChain()
      ->attachByName('stringtrim')
      ->attachByName('alpha');

$inputFilter = new InputFilter();
$inputFilter->add($input)
            ->setData(array(
                'foo' => ' Bar3 ',
            ));

echo "Before:\n";
echo $inputFilter->getRawValue('foo') . "\n"; // the output is ' Bar3 '
echo "After:\n";
echo $inputFilter->getValue('foo') . "\n"; // the output is 'Bar'

The getValue() method returns the filtered value of the ‘foo’ input, while getRawValue() returns the original value of the input.

We provide also Zend\InputFilter\Factory, to allow initialization of the InputFilter based on a configuration array (or Traversable object). Below is an example where we create a password input value with the same constraints proposed before (a string with at least 8 characters):

use Zend\InputFilter\Factory;

$factory = new Factory();
$inputFilter = $factory->createInputFilter(array(
    'password' => array(
        'name'       => 'password',
        'required'   => true,
        'validators' => array(
            array(
                'name' => 'not_empty',
            ),
            array(
                'name' => 'string_length',
                'options' => array(
                    'min' => 8
                ),
            ),
        ),
    ),
));

$inputFilter->setData($_POST);
echo $inputFilter->isValid() ? "Valid form" : "Invalid form";

The factory may be used to create not only Input instances, but also nested InputFilters, allowing you to create validation and filtering rules for hierarchical data sets.

Finally, the default InputFilter implementation is backed by a Factory. This means that when calling add(), you can provide a specification that the Factory would understand, and it will create the appropriate object. You may create either Input or InputFilter objects in this fashion.

use Zend\InputFilter\InputFilter;

$filter = new InputFilter();

// Adding a single input
$filter->add(array(
    'name' => 'username',
    'required' => true,
    'validators' => array(
        array(
            'name' => 'not_empty',
        ),
        array(
            'name' => 'string_length',
            'options' => array(
                'min' => 5
            ),
        ),
    ),
));

// Adding another input filter what also contains a single input. Merging both.
$filter->add(array(
    'type' => 'Zend\InputFilter\InputFilter',
    'password' => array(
        'name' => 'password',
        'required' => true,
        'validators' => array(
            array(
                'name' => 'not_empty',
            ),
            array(
                'name' => 'string_length',
                'options' => array(
                    'min' => 8
                ),
            ),
        ),
    ),
));