“Fatal error: Class ‘JFeedItem’ not found” When Overriding the Joomla Core

Note: This is an advanced post which mentions an unstable extension at the time of writing (November 2016). We suggest you avoid overriding the Joomla core if you’re not comfortable with your programming skills. If you need help with overriding the Joomla core, then you can always contact us!

Until very recently, we used to overwrite the core mainly to resolve performance issues. But, last week, we have discovered a not-so-new extension, an extension called Joomla Override, which allows developers to override the Joomla core. So, we decided to give this extension a chance… But, before delving into the details of our experience, let us explain the difference between overwrite and override.

In case you don’t know already, the basic difference between overwriting and overriding is that in the former, you open a Joomla core file, you make the changes, and then you upload it back. In the latter, you copy the Joomla core file (that you want to override) to a different location and you make the changes there. Obviously, overriding has a huge advantage over overwriting, and it’s that the changes don’t get wiped out with a Joomla update. Another major advantage is that all the overrides are in one location – instead of having them spread over the many folders of the Joomla website.

So, how did our experience go with using the Joomla Override plugin?

In all fairness, the experience didn’t go very well, because the moment we tried to override the Joomla feed of the homepage, we saw the following error on the homepage of the Joomla website:

Fatal error: Class ‘JFeedItem’ not found in templates/[our-client-joomla-template]/code/com_content/views/featured/view.feed.php on line 66

As mentioned above, the error was on the homepage of the Joomla website, and not on the feed page, which we thought was odd. Why would overriding the feed file affect the homepage? So we thought, it might be that we also need to override the view.html.php file (and not just the view.feed.php file), and so we copied the view.html.php file from the components/com_content/views/featured folder to the templates/[our-client-joomla-template]/code/com_content/views/featured folder.

This time, when we refreshed the page, we saw the following (different) error:

Fatal error: Cannot redeclare class ContentViewFeatured in templates/[our-client-joomla-template]/code/com_content/views/featured/view.html.php on line 0

After a long and tedious research of the above problem, we discovered that it was caused by 2 issues:

  • Joomla has the exact same class name in both the view.html.php and the view.feed.php files (for both the category and the featured views in the com_content component). We consider this to be a Joomla bug as Joomla shouldn’t have the same class name in 2 different files.

  • The Joomla Override plugin doesn’t care about the current format, and loads both the view.feed.php and the view.html.php despite the fact that they are almost never needed at the same time.

So, how did we fix the problem?

We fixed the problem the following way:

  • We opened the file component.php located under plugins/system/joomlaoverride/helper

  • Just before the following line:

    if ($params->get('extendDefault',0))

    We added the following code:

    $arrRealFileName = explode('/', $filePath);
$realFileName = $arrRealFileName[count($arrRealFileName) -1];
$format = JFactory::getApplication()->input->get('format','html');
if (stripos ($realFileName , $format) === FALSE)
	continue;

  • We saved the file and then uploaded it back. We then refreshed the homepage, and the problem was fixed!

Did things go smoothly afterwards?

Well, not really. We discovered that there were some important core files that we were not able to override. For example, we wanted to override the file cms.php which is located under the libraries/cms/application/ folder, mainly so that we can disable session activity for visitors , but we weren’t able to. Even if we were able to, the override was useless, simply because session activities take place before any plugin is loaded. So, we had to overwrite the cms.php file instead of overriding it.

In total, we had to overwrite about 4 files for a large Joomla website, which wasn’t that bad, but wasn’t that good either. In addition, we were faced by several problems when we used this extension (including the one in this post), all of them were hard to fix. Because of that, we can’t recommend using the Joomla Override plugin, in fact, we recommend against using it, until it is stable enough.

If you want to override/overwrite some core files on your Joomla website, then please contact us. We will amaze you with our professionalism, cleanliness, and our super affordable fees!

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