Form processing in Zend Framework

Question

I started studying the Zend_Form component and understand most aspects of it. I know how to add form elements and set configuration options for them, how to apply form decorators, how to add validators and filters... But today i got stuck on the processing of those forms.

There's one particular thing that just baffles me. I'll illustrate it with an example which i kept as simple as possible.

First we create the form as a separate class. Nothing special here, just a username and password field and a submit button. We'll also add a label and some filters and validators to them.

class Login_Form extends Zend_Form
{
    public function init()
    {
        $this->setaction('/user/login')
             ->setMethod('post');

        $username = new Zend_Form_Element_Text('username');
        $username->setLabel('Username:')
                 ->setRequired(true)
                 ->addFilter('StringToLower')
                 ->addValidator('NotEmpty');

        $password = new Zend_Form_Element_Password('password');
        $password->setLabel('Password:')
                 ->setRequired(true);

        $submit = new Zend_Form_Element_Submit('submit');
        $submit->setValue('Submit');

        $this->addElements(array(
            $username,
            $password,
            $submit
            ));

        return $this;  
    }
}

Next we'll create a 'user' action controller with a 'login' action method. Here, i want to check if the form got submitted (if not it should be displayed) and validate it. Notice the two identical lines of code. Although the $form object did not change in the mean time, the first produces no output, the second does.

class UserController extends Zend_Controller_Action
{
    public function loginAction()
    {
        $form = new Login_Form;

        // Check if form got submitted
        if ($this->getRequest()->isPost())
        {
            // This does not produce output
            echo 'Username: ' . $form->getValue('username');

            if ($form->isValid($_POST))
            {
                // This does produce output (same line of code as above)
                echo 'Username: ' . $form->getValue('username');
            }
            else
            {
                echo $form;
            }
        }
        else
        {
            echo $form;
        }
    }
}

If i would just want the unfiltered values, I could get them from the request object with $this->getRequest()->getPost(). I want the filtered values though (the filters are defined in the Login_Form class) so I should get them from the form object with getValues(). I find it awfully strange that the $form object changes after calling isValid() on it (which just returns a boolean and does not alter the $form object). Any help with this would be very much appreciated!

Sven Sven · Accepted Answer · 2012-10-13T19:34:19

This how the Zend_Form object works: You need to pass the actual data that was submitted into it, it does not grab it from somewhere itself. This is because the source of data can vary. One application always uses POST, someone wants to validate GET parameters as well, and a completely different application doesn't even have HTTP requests, but does want to validate input from the commandline.

I wonder why your code seems to work. First, your form doesn't even define a method - will fail for sure. Second, in your controller I would expect $form->getValue('username') to work, but the access to a property should not work - I do not see any code inside the Zend_Form source that sets public properties.

Form processing in Zend Framework

2 Answers