silverstripe-widgets/src/Model/WidgetController.php

<?php

namespace SilverStripe\Widgets\Model;

use SilverStripe\Admin\LeftAndMain;
use SilverStripe\Control\Controller;
use SilverStripe\Control\Director;
use SilverStripe\Core\ClassInfo;

/**
 * Optional controller for every widget which has its own logic, e.g. in forms.
 *
 * It always handles a single widget, usually passed in as a database
 * identifier through the controller URL. Needs to be constructed as a nested
 * controller within a {@link ContentController}.
 *
 * ## Forms
 * You can add forms like in any other SilverStripe controller. If you need
 * access to the widget from within a form, you can use
 * `$this->controller->getWidget()` inside the form logic.
 *
 * Note: Widget controllers currently only work on {@link Page} objects,
 * because the logic is implemented in {@link ContentController->handleWidget()}.
 * Copy this logic and the URL rules to enable it for other controllers.
 *
 * @package widgets
 */
class WidgetController extends Controller
{
    /**
     * @var Widget
     */
    protected $widget;

    /**
     * @var array
     */
    private static $allowed_actions = array(
        'editablesegment'
    );

    /**
     * @param Widget $widget
     */
    public function __construct($widget = null)
    {
        if ($widget) {
            $this->widget = $widget;
            $this->failover = $widget;
        }

        parent::__construct();
    }

    /**
     * @param string $action
     * @return string
     */
    public function Link($action = null)
    {
        $id = ($this->widget) ? $this->widget->ID : null;
        $segment = Controller::join_links('widget', $id, $action);

        $page = Director::get_current_page();
        if ($page && !($page instanceof WidgetController)) {
            return $page->Link($segment);
        }

        if ($controller = $this->getParentController()) {
            return $controller->Link($segment);
        }

        return $segment;
    }

    /**
     * Cycles up the controller stack until it finds a non-widget controller
     * This is needed becauseController::currreturns the widget controller,
     * which means anyLinkfunction turns into endless loop.
     *
     * @return Controller
     */
    public function getParentController()
    {
        foreach (Controller::$controller_stack as $controller) {
            if (!($controller instanceof WidgetController)) {
                return $controller;
            }
        }
        return false;
    }

    /**
     * @return Widget
     */
    public function getWidget()
    {
        return $this->widget;
    }

    /**
     * Overloaded from {@link Widget->Content()} to allow for controller / form
     * linking.
     *
     * @return string HTML
     */
    public function Content()
    {
        return $this->renderWith(array_reverse(ClassInfo::ancestry(get_class($this->widget)) ?? []));
    }

    /**
     * Overloaded from {@link Widget->WidgetHolder()} to allow for controller/
     * form linking.
     *
     * @return string HTML
     */
    public function WidgetHolder()
    {
        return $this->renderWith("WidgetHolder");
    }

    /**
     * Uses the `WidgetEditor.ss` template and {@link Widget->editablesegment()}
     * to render a administrator-view of the widget. It is assumed that this
     * view contains form elements which are submitted and saved through
     * {@link WidgetAreaEditor} within the CMS interface.
     *
     * @return string HTML
     */
    public function editablesegment()
    {
        // use left and main to set the html config
        $leftandmain = LeftAndMain::create();
        $leftandmain->setRequest($this->getRequest());
        $leftandmain->doInit();

        // Decode if fully qualified - @see Widget::ClassName
        $className = str_replace('_', '\\', $this->urlParams['ID'] ?? '');
        if (class_exists($className ?? '') && is_subclass_of($className, Widget::class)) {
            $obj = new $className();
            return $obj->EditableSegment();
        } else {
            user_error("Bad widget class: $className", E_USER_WARNING);
            return "Bad widget class name given";
        }
    }
}