Receiving only modified fields in ZF2 - php

Question

Front End
Ext Js 4.2
The config of Ext.data.writer.Writer, writeAllFields when set false only send the fields that were modified.
http://docs.sencha.com/extjs/4.2.1/#!/api/Ext.data.writer.Writer-cfg-writeAllFields
Back End
Zend Framework 2.2
class SomeForm extends Zend\Form\Form {
public function __construct($name = null, $options = array()) {
parent::__construct($name, $options);
$this->add(array(
'name' => 'id',
'type' => 'Zend\Form\Element\Hidden',
));
$this->add(array(
'name' => 'field_foo',
'type' => 'Zend\Form\Element\Text',
));
$this->add(array(
'name' => 'field_bar',
'type' => 'Zend\Form\Element\Text',
));
}
}
class SomeFormFilter extends Zend\InputFilter\InputFilter {
public function __construct() {
$this->add(array(
'name' => 'id',
'required' => false
));
$this->add(array(
'name' => 'field_foo',
'required' => true
));
$this->add(array(
'name' => 'field_bar',
'required' => true
));
}
}
In the service layer we check if the data sent is valid
http://framework.zend.com/apidoc/2.2/classes/Zend.Form.Form.html#isValid
$form->isValid()
When back end receives
Modified all fields: Request Method: PUT Form Data:
{"field_foo":"value string","field_bar":"value string", "id":"22"}
That's right.field_foo and field_bar are required and return true.
Modified only, field_foo: Request Method: PUT Form Data:
{"field_foo":"value string","id":"22"} isValid() return false
because field_bar is required.
Which way to the solution?
Remove field?
http://framework.zend.com/apidoc/2.2/classes/Zend.Form.Form.html#remove
Or?

Answer 1

Provide a different inputFilter for update operations
or
set writeAllFields to true and send and save all values

Answer 2

Validating only the fields that are interested. In this case, only the fields sent in the request.
public function foo($rawData) // array('id' => 1, 'field_foo' => 'value')
{
$form = $this->getForm(); // #var Zend\Form\Form
$group = array_keys($rawData); // array(0 => 'id', 1 => 'field_foo')
$form->setValidationGroup($group);
$form->setData($rawData); // array('id' => 1, 'field_foo' => 'value')
$isValid = $form->isValid();
// some code
}
https://framework.zend.com/manual/2.0/en/modules/zend.form.quick-start.html#validation-groups