Creating your own panels

Both the toolbar and debugger are highly configurable and customizable. To do so, you can create your own panels that collect and display the specific data you want. Below we'll describe the process of creating a simple custom panel that:

• collects the views rendered during a request;
• shows the number of views rendered in the toolbar;
• allows you to check the view names in the debugger.

The assumption is that you're using the basic project template.

First we need to implement the Panel class in panels/ViewsPanel.php:

<?php
namespace app\panels;

use yii\base\Event;
use yii\base\View;
use yii\base\ViewEvent;
use yii\debug\Panel;


class ViewsPanel extends Panel
{
    private $_viewFiles = [];

    public function init()
    {
        parent::init();
        Event::on(View::className(), View::EVENT_BEFORE_RENDER, function (ViewEvent $event) {
            $this->_viewFiles[] = $event->sender->getViewFile();
        });
    }


    /**
     * {[@inheritdoc](https://github.com/inheritdoc)}
     */
    public function getName()
    {
        return 'Views';
    }

    /**
     * {[@inheritdoc](https://github.com/inheritdoc)}
     */
    public function getSummary()
    {
        $url = $this->getUrl();
        $count = count($this->data);
        return "<div class=\"yii-debug-toolbar__block\"><a href=\"$url\">Views <span class=\"yii-debug-toolbar__label yii-debug-toolbar__label_info\">$count</span></a></div>";
    }

    /**
     * {[@inheritdoc](https://github.com/inheritdoc)}
     */
    public function getDetail()
    {
        return '<ol><li>' . implode('</li><li>', $this->data) . '</li></ol>';
    }

    /**
     * {[@inheritdoc](https://github.com/inheritdoc)}
     */
    public function save()
    {
        return $this->_viewFiles;
    }
}

The workflow for the code above is:

1. init is executed before any controller action is run. This method is the best place to attach handlers that will collect data during the controller action's execution.
2. save is called after controller action is executed. The data returned by this method will be stored in a data file. If nothing is returned by this method, the panel won't be rendered.
3. The data from the data file is loaded into $this->data. For the toolbar, this will always represent the latest data. For the debugger, this property may be set to be read from any previous data file as well.
4. The toolbar takes its contents from getSummary. There, we're showing the number of view files rendered. The debugger uses getDetail for the same purpose.

Now it's time to tell the debugger to use the new panel. In config/web.php, the debug configuration is modified to:

if (YII_ENV_DEV) {
    // configuration adjustments for 'dev' environment
    $config['bootstrap'][] = 'debug';
    $config['modules']['debug'] = [
        'class' => 'yii\debug\Module',
        'panels' => [
            'views' => ['class' => 'app\panels\ViewsPanel'],
        ],
    ];

// ...

That's it. Now we have another useful panel without writing much code.

Advanced options

Allow 'click' events in your toolbar summary block

By default an inline preview is shown when clicking on the summary on the toolbar. To override this behavior add the yii-debug-toolbar__block_ignore_click class to your root <div> in getSummary().

Events

If you need client side programmatic access to the toolbar, for example to bind JavaScript events, you can listen to the yii.debug.toolbar_attached event on the document. For example:

document.addEventListener('yii.debug.toolbar_attached', function(event) {
    var toolbar = event.target;
}