Etag support in openbmc

[Ed Tanous]

On Tue, Oct 12, 2021 at 10:31 AM Gunnar Mills <gmills at linux.vnet.ibm.com> wrote:
>
> > On Mon, Oct 11, 2021 at 8:37 PM John Broadbent <jebr at google.com
> > <mailto:jebr at google.com>> wrote:
> >
> >     I don't think bmcweb support etags. I have never seen logic from
> >     them and Ed made a comment about how bmcweb will have to support
> >     them in the future here
> >     https://github.com/openbmc/webui-vue/issues/43#issue-728321615
> >     <https://github.com/openbmc/webui-vue/issues/43#issue-728321615>
> >
>
> Yes, we don't currently support etag. As mentioned in
> https://lists.ozlabs.org/pipermail/openbmc/2021-September/027406.html
> if you plan to add, we will want to make sure we do this correctly.


+1.  Just some additional background, at one point in its history
bmcweb supported etag for the static resources (in fact, there's still
a disabled unit test for it in the repo), but it got removed at the
same time when it went from the built-in angularjs bmcweb UI, and
moved to phosphor-webui, because the etags were being generated from
the hashing procedure, which no longer happened in the bmcweb build,
so the data was harder to get.  In theory we can parse the filename,
look for the webpack-like value, and use that as the hash value for
the etag again, but in practice, it didn't really make things faster
in most UI cases, so I never really cared to add it back.

I realize you're likely talking about caching of Redfish resources,
which is a whole different (and much more complex) thing to implement.

>
> Thanks,
> Gunnar
>