Add Support for Weak ETags
mdounin at mdounin.ru
Tue Nov 12 20:54:57 UTC 2013
On Tue, Nov 12, 2013 at 12:24:54PM -0800, Piotr Sikora wrote:
> Hey Maxim,
> > I don't think that limiting the scope to gzip and gunzip is
> > correct either. From cache validation point of view, weak etags
> > are mostly identical to Last-Modified, and removing etags
> > completely should mostly follow ngx_http_clear_last_modified().
> I strongly disagree. Modifying content (via addition/sub/ssi modules)
> can change enough to consider two pages completely different (at least
> as a general rule), so I don't think that they should retain any
The intended use case for addition filter is to use add
headers/footers which don't change semantics. I.e., week entity
tags can be preserved. Much like Last-Modified header currently.
The sub and ssi remove Last-Modified and all etags by default. If
needed though, they can be configured to preserve Last-Modified
(and weak etags with a patch) with ssi_last_modified directive and
> I've got mixed feelings regarding xslt module. While I don't disagree
> as much, I think it's still safer to remove weak ETags there as well.
Much like with ssi, this is the default. I don't think we should
remove weak etags if we are explicitly configured to preserve
Last-Modified though (http://nginx.org/r/xslt_last_modified).
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