Can't help. This is impossible. An indexer is something which is called out of the Request/Session scope as it should be. The indexer's responsibility is to write/update the Search Index, when a model changed. It should not be aware from where this change has been trigered. For example: If you add Data vie a REST Service or JSON Api, there is quite a good chance, that there is not request Object and Session at all, because the user is not logged in in the Portal UI, only in the Rest Service. At this point, all your methods which rely on a Session will fail badly.
