Re: mitigating cost of 303

On 2012-01-04, at 01:59, Sandro Hawke wrote:

> On Thu, 2011-12-22 at 13:37 +0000, Steve Harris wrote:
>> FWIW I agree with him that a 303 is a very high cost to pay.
> 
> In confusion or in extra round-trips?

Round trips. Doubles the number of HTTP requests, in the worst case.

If that forces you to move from a load balancer + 2 slaves, to a highend load balancer + 4 slaves for example (pretty likely) then that's a significant outlay, and additional maintenance headache.

> I have an engineering solution to the latter, which is that hosts be
> allowed to expose (via a .well-known URI) some of the rewrite rules they
> use.   Then, if I (as a client) find myself getting lots of redirects
> from a host, I could look for this redirect-info file, and if it
> appears, I can do the redirects in the client, without talking to the
> server.   
> 
> This wouldn't be only for RDF, but I'd expect only people doing 303 to
> care enough to set this up on their hosts or have their clients look for
> it.
> 
> The hardest engineering part, I think, is figuring out how to encode the
> rewrite rules.  Each server has its own fancy way of doing it.  Like
> which version of regexps, and how to extract from the pattern space;
> lots of solutions, but we'd need to pick one.   And, tool wise, one
> would eventually like the web servers to automatically serve this file
> based on the rewrite rules they are actually using.   :-)

Another place that data could be put is the XML sitemap.

It would work if you're being crawled systematically by a small number of systems, but it doesn't help with scattered requests coming from all over the place, just means the clients are making even more requests.

I would have thought it would be better if the response from the potentially 303'd request was a "yes, but what you wanted was this URI, and here's the data for it". I don't know if there's a HTTP code that can express that currently, it's kindof in 203+Location: space, but not quite.

- Steve

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Steve Harris, CTO, Garlik Limited
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Received on Wednesday, 4 January 2012 12:05:08 UTC