Anonymous users getting same product items in cart

Question

I am using drupal commerce module, i have an issue with anonymous users, when users click on add to cart button, cart is showing extra items which are added by other anonymous users.

I am using custom code for add to cart using ajax. following is the code.

    // Add a product to cart on ajax call.
    function mymodule_custom_add_to_cart($product_id,$uid){
        $line_item = commerce_product_line_item_new(commerce_product_load($product_id));
        commerce_cart_product_add($uid, $line_item);
        $order = commerce_cart_order_load($uid);
        commerce_cart_order_refresh($order);
        // loads data array from order object
        $data = mymoudle_custom_cart_load_all_variables($order->order_id);
        $jsonencoded = json_encode($data);
        print $jsonencoded;
    }

I dont know why all anonymous users are getting same products in there cart.

Please help me to find out the issue.

UPDATE 1:

I have changed the code for anonymous user as following, then i am getting an error: EntityMetadataWrapperException: Unable to get the data property data as the parent data structure is not set. in EntityStructureWrapper->getPropertyValue() (line 451 of /entity.wrapper.inc

CHANGED CODE

    // Add a product to cart on ajax call.
    function mymodule_custom_add_to_cart($product_id,$uid){
        if($uid == 0){

            $order_id = commerce_cart_order_id($uid);
            if($order_id == false){
             $order = commerce_cart_order_new(0, 'checkout_checkout');
            } else {
             $order = commerce_order_load($order_id);
            }

            // Load whatever product represents the item the customer will be
            // paying for and create a line item for it.
            $product = commerce_product_load($product_id);
            $line_item = commerce_product_line_item_new($product, 1, $order->order_id);
            commerce_line_item_save($line_item);

            // Add the line item to the order using fago's rockin' wrapper.
            $order_wrapper = entity_metadata_wrapper('commerce_order', $order);
            $order_wrapper->commerce_line_items[] = $line_item;

            // Save the order again to update its line item reference field.
            commerce_order_save($order);

            // loads data array from order object
            $data = mymoudle_custom_cart_load_all_variables($order->order_id);
            $jsonencoded = json_encode($data);
            print $jsonencoded;
        }else{
            $line_item = commerce_product_line_item_new(commerce_product_load($product_id));
            commerce_cart_product_add($uid, $line_item);
            $order = commerce_cart_order_load($uid);
            commerce_cart_order_refresh($order);
            // loads data array from order object
            $data = mymoudle_custom_cart_load_all_variables($order->order_id);
            $jsonencoded = json_encode($data);
            print $jsonencoded;
        }
    }

UPDATE 2: ISSUE RESOLVED.

Site is crawling by googlebot, which is clicking addtocart link and its adding an product to anonymous user account automatically, so i removed link for addtocart button and used commerce addtocart form.

Answer 1

I would guess it has to do with:

$order = commerce_cart_order_load($uid);

Since all anonymous users are assigned uid:0, it could be drawing from all products currently associated with that uid (which would be all anonymous users), rather then the products from the current user's session