Content plugin doesn't add text to articles

Question

I have the following plugin written:

defined( '_JEXEC' ) or die( 'Restricted access' );

jimport( 'joomla.plugin.plugin' );

class plgContentModifyArticle extends JPlugin
{
    function plgContentModifyArticle ( &$subject, $params )
    {
        parent::__construct( $subject, $params );
    }

    function onBeforeContentSave( &$article, $isNew )
    {

        echo "Can you see this?";

        global $mainframe;
        $newText = '<b>Testtext</b>';
        $user =& JFactory::getUser(); // get the user

        $article->fulltext.=$newText;
        $article->introtext.=$newText;

        return true;
    }
}

With the following xml-file:

<?xml version="1.0" encoding="utf-8"?>
<extension type="plugin" version="3.1.0" group="content">
    <name>Modifyarticle</name>
    <version>1.0.0</version>
    <description>Modify your articles</description>
    <files>
       <filename plugin="modifyarticle">modifyarticle.php</filename>
    </files>

    <install>

    </install>
</extension>

I've made all of this based on the following tutorial: https://docs.joomla.org/J3.x:Creating_a_content_plugin

Unfortunately, it doesn't add text to a new article. And I don't have any idea on how to debug this.

Answer 1

Your plugin appears to be written for a very old version of Joomla! The event in current versions is onContentBeforeSave. You are also missing $context argument. It's a good idea to check for context to make sure that you're modifying the correct content type (e.g. article).

public function onContentBeforeSave($context, $article, $isNew)
{
    if ($context !== 'com_content.article')
    {
        return true;
    }

    // Add your code here.

    return true;
}

Other pointers:

To avoid warnings in modern PHP versions rename constructor to __construct. If you only call the parent function inside, you can remove the constructor completely.

If your plugin supports only Joomla! 3.x and above, you don't need to use jimport().

Global $mainframe variable is no longer used in Joomla! You can declare $app class variable to use the application object.

You won't see echoed text here, unless you stop the script. Instead you might want to use application's enqueueMessage() method to display a message after saving completes.

Assigning JFactory::getUser() by reference generates a notice Only variables should be assigned by reference in modern PHP versions.

defined('_JEXEC') or die;

class plgContentModifyArticle extends JPlugin
{
    protected $app;

    public function onContentBeforeSave($context, $article, $isNew)
    {
        if ($context !== 'com_content.article')
        {
            return true;
        }

        $this->app->enqueueMessage('Can you see this?');

        $newText = '<b>Testtext</b>';

        // get the user
        $user = JFactory::getUser();

        // do stuff with user, otherwise above call is not needed

        $article->fulltext  .= $newText;
        $article->introtext .= $newText;

        return true;
    }
}