How to trigger an event only on record creation and not on updation?

Question

I have a custom admin grid module. When I add an item to that grid it calls the saveAction() in the controller of my module (obviously).

I need to trigger a custom event after the record gets saved (like shown below).

public function saveAction() {
    if ($data = $this->getRequest()->getPost('tendor')) {
    try {
            $tendor = $this->_initTendor();
            $tendor->addData($data);
            $products = $this->getRequest()->getPost('products', -1);
            if ($products != -1) {
                $tendor->setProductsData(Mage::helper('adminhtml/js')->decodeGridSerializedInput($products));
            }
            $tendor->save();
            // custom event to save vendor code
            $evtData = array('tendor_info' => $data, 'tendor_instance' => $tendor);
            Mage::dispatchEvent('my_custom_tendor_save_after', $evtData);

Now I want this event to be triggered only when a new record is added and not when the existing record is edited.

How can I find the difference between creation of record and updation of a record?

can someone help me in figuring this out?

Answer 1

You have this line in your controller:

$tendor = $this->_initTendor();

I can only assume that this takes the id parameter from _GET and loads the appropriate entity from the db. You can add this line right below the line I mentioned:

$shouldDispatchEvent = !(bool)($tendor->getId());

$shouldDispatchEvent is true only if the $tendor object has an id.
Now wrap your dispatchEvent in this:

if ($shouldDispatchEvent){
    $evtData = array('tendor_info' => $data, 'tendor_instance' => $tendor);
    Mage::dispatchEvent('my_custom_tendor_save_after', $evtData);
}

[EDIT].
An other way of doing it, in your case could be this:

if ($tendor->isObjectNew()){
    $evtData = array('tendor_info' => $data, 'tendor_instance' => $tendor);
    Mage::dispatchEvent('my_custom_tendor_save_after', $evtData);
}

This will work if your model extends Mage_Core_Model_Abstract (and it should).
the member _isObjectNew is added to the model instance in the _beforeSave (see Mage_Core_Model_Abstract::_beforeSave()) method, and since you want to dispatch your event after the save is done you should be able to access it.