Magento – Check Billing/Shipping Address in Onepage Checkout from Observer

ajaxevent-observermagento-1.9onepage-checkout

I'm trying to check billing / shipping address and break onepage checkout with an error, if the addresses do not meet some conditions of the quote (e.g. some products should only be shipped to the country XY).

Approach

Make use of the event controller_action_postdispatch_checkout_onepage_saveBilling and controller_action_postdispatch_checkout_onepage_saveShipping, the observer code is something like:

    public function checkBillingAddress(Varien_Event_Observer $observer) {

    /** @var $quote Mage_Sales_Model_Quote */
    $quote = Mage::getSingleton('checkout/session')->getQuote();

    $special_products = 0;
    foreach($items as $item) {
        $sku = $item->getData('sku');
        $isGuaranteeredProduct = $helper->isGuaranteeredProduct($sku);
        $special_products++;
    }
    if($special_products > 0) {
        Mage::getSingleton('core/session')->addError(Mage::helper('core')->__('Orders with special products can only be shipped to XY!'));
    }
}

Problem

How can I return the error via AJAX and break checkout in a right way?

Thank you for your ideas.

Best Answer

You could try Mage::throwException('An error message') under the session error message. Or you can force a redirect in the section where you set the error. I had done this for another question and it seemed to work as expected inside the event observer:

    $error_message = 'Sorry, we are unable to continue, you have items in your cart that need to be delivered within Dehli';
    Mage::getSingleton('core/session')->addError($error_message);
    Mage::throwException($error_message);

Related Solutions

Onepage Checkout – Displaying Billing/Shipping Address Outside Progress Sidebar in Magento 1.9

I'm not an expert of Prototype.js, but it seems like the progress sidebar is modified by the reloadStep function of the skin/frontend/base/default/js/opcheckout.js script.

reloadStep: function(prevStep) {
    var updater = new Ajax.Updater(prevStep + '-progress-opcheckout', this.progressUrl, {
        method:'get',
        onFailure:this.ajaxFailure.bind(this),
        onComplete: function(){
            this.checkout.resetPreviousSteps();
        },
        parameters:prevStep ? { prevStep:prevStep } : null
    });
},

Where prevStep + '-progress-opcheckout' (prevStep could be billing, payment etc.) determines which block has to be edited.

One solution, but clearly not the best way, would be to add the code below just after the step-title div.

<div id="<?php echo $_stepId ?>-progress-opcheckout"></div>

As an id has to be unique, you would have to disable completely the progress sidebar, so not only hiding it.

Magento OnePage Checkout – Fixing Wrong Totals After Product Save

Okay, no responses so hopefully the following may help some poor soul who finds themselves in the same boat I was in. Credit for helping me track down the issue goes to this post on TechyTalk.info. The solution outlined there didn't apply in my case as I wasn't dealing with price rules or creating orders in the backend. However, it did help me pinpoint what I need to be concerned about, so big thanks for that! To summarize:

When using a custom totals collector, Magento's _afterLoad() method in Mage_Sales_Model_Quote can cause an excessive call to collectTotals() after a product has been modified. The call to collectTotals() is managed by the trigger_recollect flag which, is set to 1 when the product has been modified. Fine in most cases but not when certain events are triggered!

The first thing collectTotals() in Mage_Sales_Model_Quote does is to wipe out (set to zero) all of the quote totals and then call collectTotals() on all address objects it can get its hands on (Mage_Sales_Model_Quote_Address). As it turns out, however, when _afterLoad() is called on certain events after a product is modified, there are no address objects available and the quote total remains at zero when collectTotals() completes.

The second scenario I described was just a result of the way our code worked where, when a product was removed from the cart (and Magento reported that it's total price is zero), the Ajax method did not update the checkout page totals since, according to it's logic, the cart total had not changed (a zero-price product was removed).

I inspected the quote object and, unfortunately, could not find a property with which I could detect that the trigger_recollect flag has been set at product save. In addition, my custom totals collector had already re-calculated the totals in each instance that I could test for so I simply temporarily turned off the trigger_recollect while calling the parent::_afterload() in a descendant class to at least allow all other processing and events dispatched to proceed as expected. This fixed the issue in both scenarios.

Mock override:

class Some_Other_Model_Sales_Quote extends Mage_Sales_Model_Quote
{
    //... some other stuff here

    /**
     * Bypass the collectTotals() call in Mage_Sales_Model_Quote
     *
     * This still triggers all the _afterLoad() events and processing
     *
     * @return Mage_Core_Model_Abstract
     */
    protected function _afterLoad()
    {
        $triggerRecollect = $this->getTriggerRecollect();
        $this->setTriggerRecollect(false);
        $return = parent::_afterLoad();
        $this->setTriggerRecollect($triggerRecollect);
        return $return;
    }
}