Question

is there a way i can use the Alnum filter for a Zend_Form_Element_Text form element but still retain commas ? The input will be command seperated tags for an item.
Do i have to define my own filter ? Is there a way to achieve this using the ‘Callback’ filter type ?

Expected input is tag1,tag2,tag3

$tags=new Zend_Form_Element_Text('tags');
$tags->setLabel('Tags:');
$tags->addFilters(array('Alnum','StripTags','StringTrim','HtmlEntities'));

---

Update 1:

the Zend_Filter_Alnum has an option to allow whitespace which can be activated by

$tags->addFilters(array('StripTags','StringTrim','HtmlEntities',new Zend_Filter_Alnum(true)));

So the expected input will be tag1 tag2 tag3 but still if anybody could suggest me a way to make it accept tag1,tag2,tag3, it would be awesome.

Answer 1

This is just an example , it shouldn’t be used as is in a production environment :

class My_Filter_AlnumComma implements Zend_Filter_Interface
{
    public $allowComma;

    public function __construct($allowComma = false)
    {
        // have a look at a proper filter construct 
        // and change me
        $this->allowComma = (boolean) $allowComma;
    }

    public function getAllowComma()
    {
        return $this->allowComma;
    }

    public function setAllowComma($allowComma)
    {
        $this->allowComma = (boolean) $allowComma;
        return $this;
    }

    public function filter($value)
    {
        $comma = $this->allowComma ? ',' : '';
        $pattern = '/[^a-zA-Z0-9' . $comma . ']/';        

        return preg_replace($pattern, '', (string) $value);
    }
}