File::getAction

public function getAction($entity, $id, $field, $value, CRestServer $restServer = null)
{
	$errorCollection = new ErrorCollection();
	if (in_array($entity, $this->allowEntityList, true))
	{
		if ($restServer && $this->entityScope[$entity])
		{
			$authScope = $restServer->getAuthScope();
			if (!in_array($this->entityScope[$entity], $authScope, true))
			{
				$errorCollection->add(
					[
						new Error('Invalid request credentials', 'INVALID_CREDENTIALS')
					]
				);
			}
		}

		if ($errorCollection->isEmpty())
		{
			global $USER_FIELD_MANAGER;
			$userFieldsData = $USER_FIELD_MANAGER->getUserFields($entity, (int) $id, LANGUAGE_ID);

			if (
				$userFieldsData[$field]['USER_TYPE_ID'] === 'file'
				&& (int) $value > 0
				&& !empty($userFieldsData[$field]['VALUE']))
			{
				if (
					(int) $value === (int) $userFieldsData[$field]['VALUE']
					|| (
						is_array($userFieldsData[$field]['VALUE'])
						&& in_array((int) $value, $userFieldsData[$field]['VALUE'], true)
					)

				)
				{
					return BFile::createByFileId((int) $value);
				}

				$errorCollection->add(
					[
						new Error('File not found.', 'FILE_NOT_FOUND')
					]
				);
			}
			else
			{
				$errorCollection->add(
					[
						new Error('Entity not allow.', 'ENTITY_NOT_ALLOW')
					]
				);
			}
		}
	}
	else
	{
		$errorCollection->add(
			[
				new Error('Access denied.', 'ACCESS_DENIED')
			]
		);
	}

	if (!$errorCollection->isEmpty() && EngineController::getScope() === EngineController::SCOPE_REST)
	{
		/** @var  Error $error*/
		$error = $errorCollection->current();
		if ($error)
		{
			return new RestException(
				$error->getMessage(),
				$error->getCode()
			);

		}
	}

	return AjaxJson::createError($errorCollection);
}