Magento read-only and hidden product attributes - magento

Question

I would like to have some Magento product attributes that are not editable from the admin interface and some that are not visible at all in that interface (as a method of storing some persistent information about a product that should not be viewed by human users.. it's the only way of doing this that i can think of, any other suggestions are welcome).
So my question is: Do all Magento attributes have to be visible and editable from the admin interface? If not, how can they be made read-only or hidden?
I noticed that in the admin interface there are some read-only fields, so it must be possible to do this one way or another. After searching stackoverflow for this I found a possible solution involving JavaScript, but I would like to not go down that path if it's at all possible.

Answer 1

OK, it looks like it can be done after all. After adding an observer for the catalog_product_load_after event, the lockAttribute method of the Mage_Catalog_Model_Abstract class may be used to make a product attribute read-only. Here is the code for the observer method:
public function lockAttributes($observer) {
$event = $observer->getEvent();
$product = $event->getProduct();
$product->lockAttribute('attribute_code');
}

Answer 2

Since the catalog_product_load_after event is dispatched for every product load, the attributes supplied in the lock_attributes method are locked after every product load. This could have unexpected results: it is not possible to change the value of the attributes in the lock_attributes method without explicitly unlocking them.
Instead of using the catalog_product_load_after event, it suffices to add an observer for the catalog_product_edit_action event: this event is dispatched only when editing a product in the admin interface.

Answer 3

I think Aad Mathijssen and Epicurus combined have the best answer to the question, with a little clarification. As Aad points out, catalog_product_load_after is called after every product load and that means on the FrontEnd as well!
If we are looking to protect attribute fields only in the admin panels, catalog_product_edit_action is the more appropriate choice.
Your etc/config.xml will then be something like this:
<catalog_product_edit_action>
<observers>
<lock_attributes>
<class>yourmodule/observers</class>
<method>lockAttributes</method>
</lock_attributes>
</observers>
</catalog_product_edit_action>

Answer 4

No i guess its not possible from the attribute manager.
A easy quick and dirty solution would be to use css to hide the input and label.

Answer 5

I have developed exactly such extension that works for products, categories and CMS pages. You just have to define some rules and choose which attributes you want to show as read-only.
Extension URL: https://www.bubbleshop.net/magento-admin-readonly.html

Answer 6

Using this thread and some more digging around; the lockAttribute method is from an abstract class which means that it's possible to also be used on category attributes as well. I caught the 'catalog_category_load_after' observer and used it to lock my desired category attributes:
public function lockCategoryAttributes($observer) {
$event = $observer->getEvent();
$c = $event->getCategory();
$c->lockAttribute('attribute_code');
}
I'm not sure if that's the right observer to use but it works.
So yes it is possible to lock category attributes or make them readonly.

Answer 7

etc\adminhtml\events.xml
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
<event name="catalog_product_load_after">
<observer name="product_lock_attributes" instance="Vendor\Module\Observer\Lock"/>
</event>
</config>
Observer\Lock.php
namespace Vendor\Module\Observer;
class Lock implements \Magento\Framework\Event\ObserverInterface
{
public function execute(\Magento\Framework\Event\Observer $observer)
{
$event = $observer->getEvent();
$product = $event->getProduct();
$product->lockAttribute('attribute_code');
}
}