Hi Pat -
So far as we can tell the practical limit on URL length is quite large, at least in the thousands of chars, with much longer URLs occasionally seen. Most simple ADQL queries are likely much much smaller. In practice GET should work for most queries, and is simpler for the client, but I agree that POST should be supported for the more general case where queries may be very large. Again, both are parameter based (the original issue), and with modern toolkits like Tomcat, PHP, etc., they are essentially equivalent on the server side.
The simplest and most convenient solution is probably to permit either GET/POST for simple synchronous queries, but only POST for asynch queries (because these have side effects).
On Fri, 18 May 2007, Patrick Dowler wrote:
>
> IMO we have not discussed GET vs POST vs PUT, but I agree with Jeff that
> putting the query string (URLEncoded) in a GET url will likely be
> problematic. Specifically, there is a limit to the length of a URL and you
> may not be able to tell in practice (on the server side) that you passed it
> and suffered truncation. Sure the client might check the length, but then
> what?
>
> It seems to me that http POST is the next likely candidate (depending on the
> flavour of REST religion we may or may not adopt :) I like the idea of POST
> because it still allows for something simple like a page in a browser to
> submit a TAP query and doesn't limit what a more capable client might do.
>
>
> my 2c,
>
> Pat
>
> On Friday 18 May 2007 15:19, Doug Tody wrote:
> > To clarify, what I meant in my closing plenary comment was that
> > I think what we agreed was to eliminate the use of parameters for
> > query restriction (hence no POS,SIZE,BAND, no range-list constraints,
> > etc.) but not the use of the basic HTTP GET parameter mechanism
> > where we might have other general non-query constraint params such
> > as REQUEST, VERSION, FORMAT, QUERY=<adql-string>, or whatever, which
> > do not duplicate functionality found in the ADQL but which are needed
> > to compose a GET/POST operation. - Doug
>
> --
>
> Patrick Dowler
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Received on 2007-05-18Z14:48:29