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Re: Header compression: header set diff

From: James M Snell <jasnell@gmail.com>
Date: Mon, 25 Mar 2013 10:58:24 -0700
Message-ID: <CABP7RbftbeBWby5r1RJ5xOikC-ZZ6UomXyaVTF9onHLsG4hK5Q@mail.gmail.com>
To: RUELLAN Herve <Herve.Ruellan@crf.canon.fr>
Cc: Roberto Peon <grmocg@gmail.com>, Patrick McManus <pmcmanus@mozilla.com>, HTTP Working Group <ietf-http-wg@w3.org>
On Mon, Mar 25, 2013 at 10:50 AM, RUELLAN Herve

> ​[snip]​
> I you have time, we would welcome another implementation of HeaderDiff.

​Gimme about two to three weeks and I'll see if I can put it together...​

> I think we really should aim at a customizable compression mechanism: if
> you don’t want to spend too much resources (or even any resource) on
> compression, just use a simple encoder. From my experience, by using very
> few resources, you can easily divide the size of the headers by at least
> two. If you really want to save some bytes, then you can implement a very
> complex and very clever encoder.

​I tend to fear solutions that are "too clever", especially if it's not yet
completely clear how much benefit the solution will ultimately provide. In
the meantime, I'm still going to be writing the code tho ;-)​

> I think that binary-optimized headers are also interesting. We
> experimented with a few of them internally and found that a binary encoding
> for dates and integers are simple to add and provide good compaction
> improvements.

In about a week I'll have a modified draft of the BOHE draft spec that adds
binary encoding to Roberto's delta2 encoding. I can look at HeaderDiff and
add it in there also. If we focus on a limit number of value types
(specifically text, numbers, dates and binary blobs) then things can remain
very simple.

- James

> Hervé.
Received on Monday, 25 March 2013 17:59:11 UTC

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