How to get the e-tag during a get_opts operation?

[winding-lines]

Here is the flow I am trying to implement:

1. when I download an object the first time I would like to save its e-tag and content
2. on subsequent downloads I would like to use if_none_match
   a. if the tag has changed save the new content and e-tag
   b. otherwise the api will fail and I can use the local data

I don't seem to have a way to get the e-tag from a get or get_opts API call. The docs and tests I found indicate that I need to do a head to get the metadata for a given object and get the e-tag from the metadata. But this increases the number of API calls, if get had a way to return the e-tag I could implement the logic above just will calls to get.

Am I missing something?

Thanks for your advice.

[tustvold]

Unfortunately there isn't a way to do this currently, but perhaps this is something that could be added as part of #4352

[tustvold]

#4677 proposes an API change that will provide access to the etag on get