observer getting called more than once

Question

i wrote below observer to add extra price to product price based on get paramter id of product

 <catalog_product_load_after>
            <observers>
                <setcustomprice>
                    <type>singleton</type>
                    <class>Mour_Customgroup_Model_Observer</class>
                    <method>loadaftercatalog</method>
                </setcustomprice>
            </observers>
    </catalog_product_load_after>

observer.php

    public function loadaftercatalog(Varien_Event_Observer $event) {

            $pricetoadd=Mage::getModel('catalog/product')->load(233); // error caused after adding this line

            $product = $event->getEvent()->getProduct();
            $originalprice = $product->getPrice();
            $customprice = $originalprice+$pricetoadd->->getPrice();
            $product->setPrice($customprice);

   }

after adding code to observer i keep on getting error maximum nesting level of 500 reachesd i thing my observer i getting called more than once any better way to solve the issue

pls suggest

What i am trying to do :

1: there are two categories A, B if user browser any product of A he has option to buy it with any other product in B

so i pass id of product in A via get parameter and show Products of category B with added price based on id of product in get parameter

Answer 1

The event catalog_product_load_after is dispatched when calling Mage_Catalog_Model_Product::load.
In your code you call inside the observer

Mage::getModel('catalog/product')->load(233);

This will again dispatch the event catalog_product_load_after that will call the same code as above and will again dispatch the same event...and it will do this until it get tired. Apparently it gets tired after 500 loops.

I'm not sure what you are trying to achieve here, but for sure there is a better option.

but if you insist in using the code you have you can do something to stop your code from being executed when you call the second load.

Something like this:

public function loadaftercatalog(Varien_Event_Observer $event) {
    $product = $event->getEvent()->getProduct();
    if (!$product->getSkipCustomPriceObserver()) {
        $pricetoadd = Mage::getModel('catalog/product')
                          ->setSkipCustomPriceObserver(true) //this will set a flag that will be handled by the if statement above. If this flag is true your code will not be executed.
                          ->load(233); 
        $originalprice = $product->getPrice();
        $customprice = $originalprice+$pricetoadd->->getPrice();
        $product->setPrice($customprice);
     }
}