protected function purgeFiles()
    {
        //get record
        //validate and extract input
        $input = $this->processSaveInput(filter_input_array(INPUT_POST, $this->configuration['subjects'][$this->name]['CRUD']['inputFields']));
        //extract primary key value
        $primaryKeyValue = $this->extractPrimaryKeyValue($input, 'a');
        $record = $this->getByPrimaryKey($primaryKeyValue);
        $fields = array_keys($this->uploadFieldsDefinitions);
        //loop defined upload fields
        foreach($fields as $field) {
            //skip other subject field (in case this subject handles upload for other tables)
            if(!isset($record->$field)) {
                continue;
            }
            //get record field value
            $fieldValue = json_decode($record->$field);
            //skip empty field
            if(!$fieldValue) {
                continue;
            }
            //ERRORE "Cannot use object of type stdClass as array" ALLA RIGA 230
            continue;
            //get posted value
            if($this->action == 'update') {
                $a = $input[$field];
                $fieldObject = json_decode($a);
                //$a = get_object_vars($a);
                //$postedInputs = array_keys($a);
            }
            //loop inputs
            foreach((array) $fieldValue as $hash => $input) {
                //if($this->action == 'delete' || !in_array($hash, $postedInputs)) {
                if($this->action == 'delete' || !isset($fieldObject->$hash)) {
                    //loop outputs
                    foreach($input->outputs as $output) {
                        if(is_file($output->path)) {
                            unlink($output->path);
                        }
                    }
                }
            }
        }
    }