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Re: HTTP/2 Header Encoding Status Update

From: James M Snell <jasnell@gmail.com>
Date: Fri, 1 Mar 2013 07:37:44 -0800
Message-ID: <CABP7Rbc+QFQuEFocTsLZ68StriY+acqR0+DNLEnT-MXhr2MF-w@mail.gmail.com>
To: Nicolas Mailhot <nicolas.mailhot@laposte.net>
Cc: ietf-http-wg@w3.org
On Mar 1, 2013 2:44 AM, "Nicolas Mailhot" <nicolas.mailhot@laposte.net>
wrote:
>
> Mark Nottingham <mnot@...> writes:
>
> >
> > One other thing -
> >
> > On 28/02/2013, at 8:16 AM, James M Snell <jasnell@...> wrote:
> >
> > > Date values:
> > >
> > >  1. Dates are encoded as the number of seconds since a new epoch
> > > (Midnight GMT, Jan 1 1990)
> >
> > So, how many bytes does changing the epoch save us?
> >
> > I just get concerned about putting little landmines like this in...
>
> I'd really *love* to see the whole epoch concept nuked in HTTP/2 and force
> everyone to use an ISO 8601 profile like html instead
> http://www.w3.org/TR/NOTE-datetime
> (requiring UTC-only if necessary)
>
> We've already been bitten by an http product that seemed to use the same
epochs
> as everyone else (even calling them "unix epochs") but actually counted
epochs
> in local dos/windows time. The problem was un-obvious till we needed to
perform
> some cross-system analysis and discovered they disagreed on time even
though
> they all used the "same" epoch format. Getting time right in an i18n
context is
> hard enough without obfuscating the format.
>
> Do the benefits of an epoch really outweigh the benefits of avoiding time
> mistakes in an http user?
>

Iso8601 date times require a minimum of 20 ascii bytes at the second
precision level.  The uvarint epoch encoding requires a maximum of ten
bytes but will usually be around 5 or 6 for the reasonably foreseeable
future.  I have no problem with 8601 for general use but in encoding for
transmission, the epoch encoding is much more efficient.

> --
> Nicolas Mailhot
>
>
Received on Friday, 1 March 2013 15:38:11 GMT

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