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Re: Comments on Byte range draft

From: Shel Kaphan <sjk@amazon.com>
Date: Mon, 13 Nov 1995 14:55:16 -0800
Message-Id: <199511132255.OAA19699@bert.amazon.com>
To: Lou Montulli <montulli@mozilla.com>
Cc: Gavin Nicol <gtn@ebt.com>, fielding@avron.ICS.UCI.EDU, masinter@parc.xerox.com, ari@netscape.com, john@math.nwu.edu, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Lou Montulli writes:
	...
   An If-modified-since
 > request can guarantee that the object hasn't changed.  From
 > there it's just a simple matter of requesting the parts that
 > are missing. 
 > 

That makes this into a two-round-trip protocol to receive just
a part of the object (GET if-modified-since, 304, GET byte-range)
unless you want to change the semantics of GET if-modified-since,
which seems like barking up the wrong tree.  (What would it be?
GET if-modified-since unless there's a byte-range in the URL, in which
case, instead of returning the 304, return the byte-range??? Yuck!)
Orthogonality!  Orthogonality!!!

If we're actually going to *design* this part of the protocol, let's
design into it that you can pass the last-modified date (at least) to
the server along with the request, in a header, so that you can safely get
the partial resource on one request, and not muck up the meaning of
GET if-modified-since.  This also further suggests that the byte-range
should be in a header, or we should use some method other than GET,
rather than putting it into the URL, which conflates two very
different things.

Shel Kaphan
Received on Monday, 13 November 1995 15:04:32 EST

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