Modify request object in Symfony 2 - ajax

Question

i have the following code on my controller:
/**
*
* #Route("/{discountLevelItemId}/manage-product/update", name="discountlevel_manage_product_update", defaults={"_format"="json"} )
* #Method("POST")
*/
public function manageProductUpdateAction($discountLevelItemId, Request $request)
{
$em = $this->getDoctrine()->getEntityManager();
$entity = $em->getRepository('CIInventoryBundle:DiscountLevelItem')->find($discountLevelItemId);
$form = $this->createForm(new DiscountLevelItemCollectionType(), $entity);
$form->bindRequest($request);
if ($form->isValid()) {
//remove items without discount type
foreach ($entity->getDiscountLevelItemProducts() as $item) {
if (!$item->getDiscountType()) {
$entity->getDiscountLevelItemProducts()->removeElement($item);
$em->remove($item);
}
}
$em->persist($entity);
$em->flush();
$responseData = array(
'status' => 'success',
'message' => 'Supplier product discounts successfully saved.'
);
} else {
$responseData = array(
'status' => 'error',
'form' => $this->renderView('CIInventoryBundle:DiscountLevel:manageProducts.html.twig', array(
'entity' => $entity,
'form' => $form->createView()
))
);
}
return new Response(json_encode($responseData), 200, array('Content-Type'=>'application/json'));
}
This action is called via ajax. Before calling this controller i filtered some data out like so:
initForm: function() {
//submit form function
var options = {
delegation: true,
dataType: "json",
beforeSubmit: function(arr, $form, options) {
//holds objects every four looping
var tempArray = new Array();
//holds changed objects that will only be submitted in the server.
var changedArray = new Array();
var found = false;
var idx = 1;
//get the token then remove from arr.
changedArray.push(arr.splice(arr.length-1,1)[0]);
for (var j = arr.length-1; j >= 0; j--) {
var obj = arr[j];
if ( viewCtrl.dliProductsChanged.indexOf(obj.value) != -1 ) {
found = true;
}
tempArray.push(arr[j]);
if(idx % 4 == 0) {
if (found == true) {
for(var i = 0; i < tempArray.length; i++){
changedArray.push(tempArray[i]);
}
found = false;
}
tempArray.length = 0;
}
idx++;
}
arr.length = 0;
for(var i = 0; i < changedArray.length; i++){
arr.push(changedArray[i]);
}
viewCtrl.dliProductsChanged.length = 0;
$form.find( ".submit-button" ).button( "loading" );
$form.find( ".discount-value, .trucking" ).addClass( "uneditable-input" );
$form.find( ".discount-type" ).attr( "readonly", true );
},
success: function(responseText, statusText, xhr, $form) {
if ( responseText.status == "success" ) {
viewCtrl.modal.modal( "hide" );
$.growl.notice({ title: "<strong>Saved</strong>", message: responseText.message, size: "large", duration: 5000, location: "br" });
viewCtrl.dliProductsChanged.length = 0;
} else {
viewCtrl.modal.find( ".modal-content" ).html( responseText.form );
}
$form.find( ".submit-button" ).button( "reset" );
}
};
$( "#manage-products-form" ).ajaxForm( options );
},
My question is, how can i repopulate the form with data i filtered out when the form gets invalid? The first thing came out of my mind is modifying the request object and then rebinding it again but i dont know how to implement that...
Any insights?
PS: I user JQUERY Form Plugin on form submission.
Thanks!