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Re: 'PUT' transaction reconsidered (was Re: two-phase send concerns )

From: Alex Hopmann <hopmann@holonet.net>
Date: Thu, 14 Dec 1995 19:45:46 -0800
Message-Id: <199512150345.TAA23661@nic.cerf.net>
To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Rohit Khare wrote:
>Basically, you probe (in GET or HEAD) to get a lease; if you do get a lease,  
>for the next delta-t seconds, you're entitled to use that lease in a  
>Authorization: header (using the LEASE scheme) to execute an exclusive PUT or  
>POST or PATCH.
Well I don't know about the "lease" idea, but I definatelly think you are on
the right track with the "you probe" idea. One of the beauties of HTTP is
that there is a very clear model:

Step 1: Client makes a request. Server just receives.
Step 2: Server sends a response. Client just receives.

The two-phase send changes some of the clarity of this model. However it is
possible to accomplish much the same thing (At least the goals as Roy
expressed them in Dallas), by doing a probe:

Transaction #1 "The Probe"
Client asks the server if the following send is acceptable, using a GET,
HEAD, or some new method. Server responds.

Transaction #2 "The Send"
If the server answered transaction #1 in the affirmative, client sends the data.

Now a couple of notes:
1) Don't pay too much attention to the word transaction above. I know it
implies more than I mean, but I can't think of a better word at this minute.
2) The above only makes sense (in terms of performance) in the context of
persistant connections.
3) In situations where clients either don't care, or are sure that their
"send" is acceptable, they can skip the "probe".

Alex Hopmann
ResNova Software, Inc.
hopmann@holonet.net
Received on Thursday, 14 December 1995 19:49:41 EST

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