Linkr API: Plugin Events

Linkr uses events to interact with other extensions.

Related readings:

onLinkrGetLinks

This event is called when the view is first being displayed. It passes one argument (current installed version of Linkr) and expects an associative array of titles and javascript statements to be returned. Here's an example of a plugin that would create links for a fictitious extension "Foo":

class plgContentFoo extends JPlugin
{
    // Your code...
 
    // As of 2.2.2, $version is an interger
    function onLinkrGetLinks( $version )
    {
        return array(
            // Link title => Javascript statement
            'Foo' => 'FooJavaScriptFunc'
        );
    }
}

NOTE: As of 2.2.2, the version is passed as an interger i.e. 222 instead of 2.2.2

The link "Foo" has been added to the other links

onLinkrLoadJS

This is where the plugin would return the javascript needed for it to work. It is recommended to use objects and variables, but you're plugin can work just fine with a combination of functions (see Object-Oriented Programming). Here's an example from the "Foo" plugin:

class plgContentFoo extends JPlugin
{
    // Your code...
 
    // As of 2.2.2, $version is an interger
    function onLinkrLoadJS( $version )
    {
        // URL for AJAX requests. Be sure to use full URLs
        $r = JURI::base() .'index.php?option=com_foo'.
                '&tmpl=component&view=foo';
 
        // Security measure to prevent CSRF*
        $r .= '&'. JUtility::getToken() .'=1';
 
        // Javascript
        return
        'var LinkrFoo =
        {
            requestURL:"'. $r .'",
            /* etc, etc */
        }';
    }
}

*Cross Site Request Forgery attacks
Note that the plugin is not required to return anything. You may choose to include the javascript yourself:

class plgContentFoo extends JPlugin
{
    // Your code...
 
    function onLinkrLoadJS( $version )
    {
        if ( $version >= 222 )
        {
            // External javascript
            $doc = & JFactory::getDocument();
            $doc->addScript( 'path/to/script.js' );
 
            return '';
        }
    }
}

Tips / Tricks

You can make a link available only in the back-end. This is how you would check to see if the article is being edited from the front-end or back-end:

class plgContentFoo extends JPlugin
{
    // Your code...
 
    function onLinkrLoadJS( $version )
    {
        global $mainframe;
 
        if ( $mainframe->isAdmin() ) {
            // execute code
        }
    }
}

Example

Here is what your plugin might look like:

 
// Plugin Librairies
jimport( 'joomla.plugin.plugin' );
 
// Foo Plugin
class plgContentFoo extends JPlugin
{
    // Constructor
    function plgContentFoo( &$subject, $config ) {
        parent::__construct( $subject, $config );
    }
 
    // Send links to Linkr
    function onLinkrGetLinks( $version )
    {
        return array(
            // Link title => Javascript statement
            'Foo' => 'FooJavaScriptFunc'
			);
    }
 
    // Scripts
    function onLinkrLoadJS( $version )
    {
        $doc = & JFactory::getDocument();
        $doc->addScript( 'plugins/content/foo/script.js' );
 
        // URL for AJAX requests. Be sure to use full URLs
        $r = JURI::base() .'index.php?option=com_foo'.
                '&tmpl=component&view=foo&'.
                JUtility::getToken() .'=1';
 
        return 'LinkrFoo.init("'. $r .'")';
    }
}

last updated aug 29 2008