basho/riak_kv — pull request #254 by seancribbs (2011-12-02 21:42:13+00:00)
Title: Return ETag and Last-Modified with returnbody=true and siblings

Associated bugs:

* https://issues.basho.com/show_bug.cgi?id=1020
* https://issues.basho.com/show_bug.cgi?id=1297

Different but related issues to our capability for conditional requests, most specifically `PUT`s:

1. The client is unable to cache or validate previous responses when siblings are present because neither `ETag` nor `Last-Modified` are included in the response.
2. When using `returnbody=true` even in the case where siblings are not generated, neither `Last-Modified` nor `ETag` are present in response, even though we claim it has the same semantics as the response of a `GET` following the `PUT`.

Gotcha:

In the case of siblings, we should likely be returning "weak" entity tags (two available representations that are not the same content have the same ETag), but there are some other cases where we do not.