Hide product based on cookie/session value

[deshume]

Hello,

Is it possible to show/hide a product based on an arbitrary customer condition, e.g. a cookie value, for both logged in and out users?

For example, if a user clicks a custom 'share' button (from my module) I'd like to add a value to a cookie/session/storage, where thereafter they are able to see additional products.

I know products can be shown/hidden by a customer groups extension, however I can't add customers to a group without them being logged in. Also later there may be a need to use multiple cases of the above and a customer appears (?) to only be able to be within one customer group.

Alternatively, if hiding the products isn't possible, if there is a way of disallowing the add to cart/checkout of a product based on such a condition that would be just as good.

[MageBuzz]

After saving condition in cookies, you may use an event to check and hide product / add to cart button. For hiding products, you may use this event: catalog_product_collection_load_before 

<catalog_product_collection_load_before>
  <observers>
    <magebuzz_hide_product>
        <class>modulename/observer</class> 
       <method>hideProducts</method>
    </magebuzz_hide_product>
  </observers>
</catalog_product_collection_load_before>

In you can get value from cookie to check on Observer:

$condition = Mage::getSingleton('core/cookie')->get('cookie_name');
If ($condition) {
   // find products to hide
   $productIds = array();
   $observer->getCollection()
       ->addFieldToFilter('entity_id', array(
             'nin' => $productIds,
      )
   );
}

Hope this helps.