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Re: Comments on Byte range draft

From: Lou Montulli <montulli@mozilla.com>
Date: Mon, 13 Nov 1995 17:32:56 -0800
Message-Id: <30A7F1C8.41C6@mozilla.com>
To: Larry Masinter <masinter@parc.xerox.com>
Cc: ietf-lists@proper.com, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Larry Masinter wrote:
> 
> Wait wait, I keep on saying "if-not-modified-since" and you keep on
> replying "if-modified-since".
> 
> Normally, GET with caching uses 'if-modified-since', i.e., give me the
> data if it's newer than/different from what I already have.
> 
> However, GET of a byte range need the converse. It's "give me this
> byte range of this object, UNLESS the object is newer than/different
> from what I already have".
> 
> The sense is different. HTTP doesn't have a "if-not-modified-since",
> and would need it if you want byte ranges to actually work with data
> that might change.

I agree with you.  I think that "if-not-modified-since" would
be a great addition and would work well for byte-ranges.
It should be tied into the header some how though.

Maybe we should make "if-not-modified-since" an optional
attribute to the request-range header.

Therefore a byte range request would look like:

GET /byterange-capable-document HTTP/1.0
Request-Range: bytes=500-999; if-not-modified-since="DATE"

We should also be able to send size checksums, so we
could add 'if-size-equal="LENGTH"' as well.

:lou
-- 
Lou Montulli                 http://www.netscape.com/people/montulli/
       Netscape Communications Corp.
Received on Monday, 13 November 1995 17:39:49 EST

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