Zend_Filter provides a library of static methods for filtering data. For input filtering, you should use Section 5.2, “Zend_Filter_Input” instead, because it provides a framework for filtering input using the methods provided by this class. However, because Zend_Filter_Input is designed primarily for arrays, Zend_Filter can be useful for filtering scalars, because it behaves like PHP's string functions:

    <?php
    
    $alphaUsername = Zend_Filter::getAlpha('John123Doe');
    
    /* $alphaUsername = 'JohnDoe'; */
    
    ?>
        

In each of these use cases, $value represents an arbitrary scalar value.

Whitelist Filtering:

    <?php
    
    if ($email = Zend_Filter::isEmail($value)) {
        /* $email is a valid email format. */
    } else {
        /* $email is not a valid email format. */
    }
    
    ?>
        

Blind Filtering:

    <?php
    
    $alphaName = Zend_Filter::getAlpha($value);
    
    ?>
        

Blacklist Filtering:

    <?php
    
    $taglessComment = Zend_Filter::noTags($value);
    
    ?>