Item::prepareValue

protected function prepareValue(UserField $userField, BitrixRpaModelItem $item)
{
	$value = $item->get($userField->getName());

	if(is_object($value))
	{
		if($value instanceof Date)
		{
			return $value;
		}
		if(class_exists($value) && method_exists($value, '__toString'))
		{
			return (string) $value;
		}

		return null;
	}

	if($userField->isBaseTypeFile() && $this->getScope() === self::SCOPE_REST)
	{
		if(is_array($value) && $userField->isMultiple())
		{
			foreach($value as &$file)
			{
				if($file > 0)
				{
					$file = [
						'id' => $file,
						'url' => Driver::getInstance()->getUrlManager()->getFileUrl($item->getType()->getId(), $item->getId(), $userField->getName(), $file),
					];
				}
			}
		}
		elseif($value > 0)
		{
			$value = [
				'id' => $value,
				'url' => Driver::getInstance()->getUrlManager()->getFileUrl($item->getType()->getId(), $item->getId(), $userField->getName(), $value),
			];
		}
	}

	return $value;
}