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Re: Push and Caching

From: Martin Thomson <martin.thomson@gmail.com>
Date: Tue, 19 Aug 2014 10:25:20 -0700
Message-ID: <CABkgnnWvKgyDcm-1jEKZUA2Qza9M46X+X_QybwuqRwvSUrTjNw@mail.gmail.com>
To: Mike Bishop <Michael.Bishop@microsoft.com>, Mark Nottingham <mnot@mnot.net>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
On 19 August 2014 08:21, Mike Bishop <Michael.Bishop@microsoft.com> 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.
Received on Tuesday, 19 August 2014 17:25:48 UTC

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