Thread: Zend_Filter_Input doesn't validate radio and checkbox if not checked

I have a form:

[HTML]<form method="post" id="validatable-form" runat="vdaemon">
<label>Name: </label>
<input type="text" name="name" value="<?php echo $_POST['name'] ?>" /><br />

<label>Date of birth: </label>
<input type="text" name="dob" value="<?php echo $_POST['dob'] ?>" /><br />

<input type="radio" name="sex" value="m" />Male<br />
<input type="radio" name="sex" value="f" />Female<br />

<label>Phone</label>
<input type="text" name="phone" value="<?php echo $_POST['phone'] ?>" /><br />

<input type="submit" value="Go!" />

</form>[/HTML]

And I have some validation:

[PHP]/** input filter */
$validators = array(
'name' => array(
'Alpha'
),
'dob' => array(
array('Regex', '/[0-9\/\- ]/'),
array('StringLength', 8, 10)
),
'sex' => array(
array('NotEmpty'),
array('StringLength', 1, 1),
array('Regex', '/[fm]/')
)
);
$filters = array(
'*' => 'StringTrim'
);

$input = new Zend_Filter_Input($filters, $validators, $_POST);

echo '<h2>Value: '.$input->getUnescaped('name').' - '.$input->getUnescaped('sex').'</h2>';

if($input->isValid()){
echo 'The data is valid!';
}else{
echo 'The data is invalid, failed with reasons: ';
echo '<pre>';
var_dump($input->getMessages());
echo '</pre>';

}[/PHP]

Problem is when the form is submitted with no sex selected (both radios are un-selected), Zend_Filter_Input fails to validate that sex is not empty, it does not report an error. This is due to the post array not containing a key called "sex", and the same happens when checkboxes are not checked.

One way I might be able to get it working is

[PHP]$_POST = array_merge($defaultParams, $_POST);
$input = new Zend_Filter_Input($filters, $validators, $_POST);[/PHP]

But this seems a bit hack-ish, is there a better solution for this problem?