Contao\DC_Folder::__construct PHP Method

    public function __construct($strTable)
    {
        parent::__construct();
        /** @var SessionInterface $objSession */
        $objSession = \System::getContainer()->get('session');
        // Check the request token (see #4007)
        if (isset($_GET['act'])) {
            if (!isset($_GET['rt']) || !\RequestToken::validate(\Input::get('rt'))) {
                $objSession->set('INVALID_TOKEN_URL', \Environment::get('request'));
                $this->redirect('contao/confirm.php');
            }
        }
        $this->intId = \Input::get('id', true);
        // Clear the clipboard
        if (isset($_GET['clipboard'])) {
            $objSession->set('CLIPBOARD', array());
            $this->redirect($this->getReferer());
        }
        // Check whether the table is defined
        if ($strTable == '' || !isset($GLOBALS['TL_DCA'][$strTable])) {
            $this->log('Could not load data container configuration for "' . $strTable . '"', __METHOD__, TL_ERROR);
            trigger_error('Could not load data container configuration', E_USER_ERROR);
        }
        // Check permission to create new folders
        if (\Input::get('act') == 'paste' && \Input::get('mode') == 'create' && isset($GLOBALS['TL_DCA'][$strTable]['list']['new'])) {
            throw new AccessDeniedException('Attempt to create a new folder although the method has been overwritten in the data container.');
        }
        // Set IDs and redirect
        if (\Input::post('FORM_SUBMIT') == 'tl_select') {
            $ids = \Input::post('IDS');
            if (empty($ids) || !is_array($ids)) {
                $this->reload();
            }
            // Decode the values (see #5764)
            $ids = array_map('rawurldecode', $ids);
            $session = $objSession->all();
            $session['CURRENT']['IDS'] = $ids;
            $objSession->replace($session);
            if (isset($_POST['edit'])) {
                $this->redirect(str_replace('act=select', 'act=editAll', \Environment::get('request')));
            } elseif (isset($_POST['delete'])) {
                $this->redirect(str_replace('act=select', 'act=deleteAll', \Environment::get('request')));
            } elseif (isset($_POST['cut']) || isset($_POST['copy'])) {
                $arrClipboard = $objSession->get('CLIPBOARD');
                $arrClipboard[$strTable] = array('id' => $ids, 'mode' => isset($_POST['cut']) ? 'cutAll' : 'copyAll');
                $objSession->set('CLIPBOARD', $arrClipboard);
                $this->redirect($this->getReferer());
            }
        }
        $this->strTable = $strTable;
        $this->blnIsDbAssisted = $GLOBALS['TL_DCA'][$strTable]['config']['databaseAssisted'];
        // Check for valid file types
        if ($GLOBALS['TL_DCA'][$this->strTable]['config']['validFileTypes']) {
            $this->arrValidFileTypes = \StringUtil::trimsplit(',', strtolower($GLOBALS['TL_DCA'][$this->strTable]['config']['validFileTypes']));
        }
        // Call onload_callback (e.g. to check permissions)
        if (is_array($GLOBALS['TL_DCA'][$this->strTable]['config']['onload_callback'])) {
            foreach ($GLOBALS['TL_DCA'][$this->strTable]['config']['onload_callback'] as $callback) {
                if (is_array($callback)) {
                    $this->import($callback[0]);
                    $this->{$callback[0]}->{$callback[1]}($this);
                } elseif (is_callable($callback)) {
                    $callback($this);
                }
            }
        }
        // Get all filemounts (root folders)
        if (is_array($GLOBALS['TL_DCA'][$strTable]['list']['sorting']['root'])) {
            $this->arrFilemounts = $this->eliminateNestedPaths($GLOBALS['TL_DCA'][$strTable]['list']['sorting']['root']);
        }
    }