com_clubs/src/site/controllers/parts.json.php

<?php

use Joomla\CMS\MVC\Controller\BaseController;
use Joomla\CMS\Response\JsonResponse;
use Joomla\CMS\Factory;

// No direct access.
defined('_JEXEC') or die;

abstract class UserException extends Exception {}
class InvalidUserDataException extends UserException {}

class ClubsControllerParts extends BaseController
{
    
    public function edit()
    {
        $auth = new ClubsHelperAuth();
        $user = $auth->getCurrentUser();
        $app = Factory::getApplication();
        $post = $app->input->post;
        
        try
        {
            $ret = $this->callMethod($user, $post);
            echo new JsonResponse($ret);
        }
        catch(UserException $e)
        {
            echo new JsonResponse($e);
        }
        
    }
    
    /**
     * @param CommonClubsModelUser $user
     * @param JInput $post
     */
    private function callMethod($user, $post)
    {
        switch($post->getCmd('partname'))
        {
            case 'user.name':
                return $this->editUserName($user, $post);
        }
    }
    
    private function editUserName($user, $post)
    {
        $name = $post->getString('name');
        if(strlen($name) < 5)
            throw new InvalidUserDataException("Der Name muss mindestens 5 Zeichen lang sein.");
        
        $user->setName($name);
        $user->save();
        return 'index.php?option=com_clubs&view=mypage&layout=parts&type=name';
    }
    
}