Zend Form Validator : Element A or Element B

Question

I have two fields in my Zend Form, and i want to apply the validation rule that ensures the user enters either one of the these two fields.

    $companyname = new Zend_Form_Element_Text('companyname');
    $companyname->setLabel('Company Name');
    $companyname->setDecorators($decors);
    $this->addElement($companyname);

    $companyother = new Zend_Form_Element_Text('companyother');
    $companyother->setLabel('Company Other');
    $companyother->setDecorators($decors);
    $this->addElement($companyother);

How can i add a validator that will look at both fields?

Answer 1

I haven't come across such a solution, but it's perfectly valid so +1.

I would extend Your_Form::isValid() to include a manual check for the values of those two elements.

If all fields pass their own individual validators, this validation probably belongs on the form as-a-whole and such it could be placed on the validation of the form instead of the fields. Do you agree with this line of thinking?

Answer 2

I agree with @chelmertz that a feature like this does not exists.

What I don't agree is extending Your_Form::isValid(). Instead, I'd write a custom Validator that accepts the values of both form elements that have to have a value. This way I could reuse it on arbitrary form elements. This is somewhat similar to the Identical Validator.

Answer 3

See the 'Note: Validation Context' on at this page. Zend_Form passes the context along to every Zend_Form_Element::isValid call as the second parameter. So simply write your own validator that analyzes the context.

EDIT:
Alright, I thought I'ld take a shot at this myself. It's not tested, nor is it a means to all ends, but it will give you a basic idea.

class My_Validator_OneFieldShouldBePresent extend Zend_Validator_Abstract
{
    const NOT_PRESENT = 'notPresent';

    protected $_messageTemplates = array(
        self::NOT_PRESENT => 'Field %field% is not present'
    );

    protected $_messageVariables = array(
        'field' => '_field'
    );

    protected $_field;

    protected $_listOfFields;

    public function __construct( array $listOfFields )
    {
        $this->_listOfFields = $listOfFields;
    }

    public function isValid( $value, $context = null )
    {
        if( !array( $context ) )
        {
            $this->_error( self::NOT_PRESENT );

            return false;
        }

        foreach( $this->_listOfFields as $field )
        {
            if( isset( $context[ $field ] ) )
            {
                return true;
            }
        }

        $this->_field = $field;
        $this->_error( self::NOT_PRESENT );

        return false;
    }
}

Usage:

$oneOfTheseFieldsShouldBePresent = array( 'companyname', 'companyother' );

$companyname = new Zend_Form_Element_Text('companyname');
$companyname->setLabel('Company Name');
$companyname->setDecorators($decors);
$companyname->addValidator( new My_Validator_OneFieldShouldBePresent( $oneOfTheseFieldsShouldBePresent ) );
$this->addElement($companyname);

$companyother = new Zend_Form_Element_Text('companyother');
$companyother->setLabel('Company Other');
$companyother->setDecorators($decors);
$companyname->addValidator( new My_Validator_OneFieldShouldBePresent( $oneOfTheseFieldsShouldBePresent ) );
$this->addElement($companyother);