ActionsHandler.php

<?php

class ActionsHandler {
    /**
     * @var DocumentParser
     */
    protected $modx;
    protected $input;
    protected $action;

    function __construct(DocumentParser $modx)
    {
        $this->modx = $modx;
        $this->input = $this->getInput();
        $this->action = $this->prepareActionName($this->input['q']);
    }


    public function handle()
    {
        if ( ! $this->action || ! method_exists($this, $this->action)) return null;

        $data = $this->{$this->action}();

        return $this->response($data);
    }


    protected function getInput()
    {
        $input = array_merge($_GET, $_POST);

        return $input;
    }


    protected function prepareActionName($action)
    {
        $action = preg_replace('/[^a-z]/', '', $action);

        if ( ! $action) return null;

        return $action . 'Action';
    }


    protected function success($message = '', $data = [])
    {
        return ['error' => false, 'success' => true, 'data' => $data, 'message' => $message];
    }


    protected function failure($message = '')
    {
        return ['error' => true, 'success' => false, 'message' => $message];
    }


    protected function response($data = [])
    {
        return json_encode($data, JSON_UNESCAPED_UNICODE);
    }


    protected function helloAction()
    {
        return $this->success('Hello message', ['hello' => 'Hello, World!']);
    }

}