Re: Increasing precision of Last-Modified header to allow sub-second granularity?

Julian Reschke <julian.reschke@gmx.de> Tue, 31 January 2012 21:09 UTC

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Date: Tue, 31 Jan 2012 22:08:19 +0100
From: Julian Reschke <julian.reschke@gmx.de>
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To: David Booth <david@dbooth.org>
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Subject: Re: Increasing precision of Last-Modified header to allow sub-second granularity?
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On 2012-01-31 19:31, David Booth wrote:
> Not sure where to ask this, but . . .
>
> Has there been any thought or discussion of allowing the Last-Modified
> header to (optionally) carry more precision that one second, for the
> benefit of clients that wish to reliably detect when a server has
> changed its output faster than once per second?  For example:
>
>    Last-Modified: Fri, 27 Jan 2012 20:21:10.011483 GMT

I don't think this has been mentioned so far.

> Note that it is possible to get around the current one-second limitation
> using ETags, but it would be nice if finer precision could be indicated
> directly in the Last-Modified header.

Not sure what this buys you compared to an ETag?

> I'm assuming that this is out of scope for the current HTTPbis charter,
> so I'm mostly asking this regarding potential future work.  But the
> "Potential Work" page is almost empty, and hasn't been updated in 16
> months:
> http://trac.tools.ietf.org/wg/httpbis/trac/wiki/PotentialWork
>
> Has this been discussed?  If not, does the suggestion belong?

I think the Wiki page is a good pace to record this as proposal.

Best regards, Julian