Was checking out this tutorial "http://book.cakephp.org/2.0/en/models/data-validation.html" only seem to explain validating on form fields.
So what If I want to validate params or input data.
If I have this controller, where I want to validate a this "campaignId"?:
public function agency($campaignId = null){
if ($this->request->is('get')){
$campaignId;
...
}