Re: Push and Caching

[Martin Thomson <[e-mail]>]

On 19 August 2014 08:21, Mike Bishop <[e-mail]> wrote:
> I missed when that change happened.  Can someone with better git-fu remind
> me?  Was there list discussion?

https://github.com/http2/http2-spec/commit/3cec55e8

The change title: untangle relationship between pushing, promising, and caching

-          A server can only push responses that are cacheable (see
<xref target="HTTP-p6" x:fmt=","
-          x:rel="#response.cacheability"/>); promised requests MUST
be safe (see <xref
-          target="HTTP-p2" x:fmt="," x:rel="#safe.methods"/>) and
MUST NOT include a request body.
+          A server can only push requests that are safe (see <xref
target="HTTP-p2" x:fmt=","^M
+          x:rel="#safe.methods"/>), cacheable (see <xref
target="HTTP-p6" x:fmt=","^M
+          x:rel="#response.cacheability"/>) and do not include a
request body.^M

This was part of what was intended to be an editorial fix, along with
a large bunch of other edits
(https://github.com/http2/http2-spec/commits/master?page=18) and I
missed the subtle, but substantive change in the midst of the rest.

I think that the `Cache-Control: nocache` response is a useful
feature.  I do remember being careful to permit uncacheable responses,
knowing that this would be an important use case.  I want to be able
to use push to trivially replace long-polling and this would help with
that.

Maybe Mark can defend his change.