Heya,
I'm pleased to announce the first preview version of my Dropbox river for
Elasticsearch. https://github.com/dadoonet/dropbox
It will help to index your dropbox content (files) into Elasticsearch.
README describe how to install it.
Note that with this plugin, you have also a REST endpoint to generate your
users token and secret.
Comments are welcome. I will really appreciate any feedback.
It's a preview so don't use it in production by now as I must do more tests.
It will next included in the scrutmydocs.org project as a new river.
Hope it will help some of you.
--
David 
Twitter : @dadoonet / @elasticsearchfr / @scrutmydocs