Question

I have been wondering about this for a while. What if Magento has written a core Observer class and performs a functionality that you do not want it to execute, or you want to rewrite it? Is there a way to say, don’t use this method in an Observer, just use mine. If I setup a method for my own Observer won’t it just do the core functionality first and then whatever I have implement?

For example, Magento wants to save some data to the database in an Observer method, but I don’t want it to save that data at all, I want it to save some other data that I have added columns or attributes to the database for.

Answer 1

Standard caveat about class overrides being the last resort for implementing your own functionality

It’s probably possible to fiddle with the loading of the Magento global config to strip out a core Magento Observer, but there’s no supported way for doing it.

However, consider how the Core observers are configured.

<adminhtml>
    <events>
        <cms_wysiwyg_config_prepare>
            <observers>
                <widget_observer>
                    <class>widget/observer</class>
                    <method>prepareWidgetsPluginConfig</method>
                </widget_observer>
            </observers>
        </cms_wysiwyg_config_prepare>
    </events>
</adminhtml>

Observers are Magento Model classes. If a Model’s been configured with the URI/path based syntax

<class>widget/observer</class>

as opposed to a full PHP class name

<class>Mage_Widget_Model_Observer</class>

you can create an override for the Observer Model class (just as you can for any other Model). If a PHP class name’s been used, you’re out of luck. (You could place a local file in local/Mage/Widget/Model/Observer.php if you’re willing to take on the responsibility of maintenance, but I don’t recommend it)

So, to override the above observer, you would

1. Create a custom module that include an override for the class Mage_Widget_Model_Observer.

2. In your override class, either redeclare prepareWidgetsPluginConfig to do what you want OR override the specific method. This could include a empty method to completely remove the functionality.