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Re: pipelining vs. deferred content

From: Jeff de la Beaujardiere <delabeau@iniki.gsfc.nasa.gov>
Date: Thu, 27 Mar 1997 10:02:11 -0500
Message-Id: <199703271502.KAA00640@iniki.gsfc.nasa.gov>
To: mogul@pa.dec.com
Cc: http-wg@cuckoo.hpl.hp.com

Jeffrey Mogul writes:
> Actually, this doesn't entirely solve the problem.  If you have an HTML
> file with, say, 41 embedded images, and image #3 will take 10 seconds to
> precompute at the server, you would really like to be able to use the
> network to load images #4 - #41 while that is happening.  The IMG tag
> allows the browser to render the bounding box, but it doesn't solve the
> retrieval serialization.

Thank you for restating what I had not stated clearly enough.  I am indeed
referring to a situation wherein the image will not yet exist if the client
requests it immediately upon parsing the HTML.

> Another approach that would probably work with HTTP/1.1, but would not be
> compatible with HTTP/1.0 clients, would be for the server to respond to
> the initial request for the "slow" image by sending
>   HTTP/1.1 503 Service Unavailable
>   Retry-after: 10

Interesting idea which should help with pipelined requests.  It does,
however, require invoking a second script on the server.  I want a single
response to send HTML, pause while the image is generated, and then send the
image.

> I think this is a problem worthy of some more thought, but I doubt we'll
> solve it before we need to progress HTTP/1.1 to Draft Standard.

I would not dream of suggesting that this idea be included in 1.1.

--Jeff dLB


  = J-F Pitot de La Beaujardiere
  = delabeau@iniki.gsfc.nasa.gov
  = http://globe2.gsfc.nasa.gov/
Received on Thursday, 27 March 1997 07:05:25 EST

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