- From: Miles Sabin <MSabin@interx.com>
- Date: Mon, 5 Feb 2001 17:56:13 -0000
- To: uri@w3.org
Mark Baker wrote, > Miles Sabin wrote: > > Sadly HTTP URLs _will_ be resolved even when that's > > unnecessary for them to be meaningful as bare identifiers. > > And if they are, then servers (particularly ones hosting > > extremely popular DTDs or namespaces) might well be in > > trouble. > > Will they be resolved by the origin server enough that it's a > problem? How do you know? What's 'often enough' to cause a problem? It could be quite a low frequency. How do I know? I don't ... and I don't want hostages left to fortune. > > xml-dev's RDDL or anything similar, if widely adopted, would > > put namespaces more or less on a par with DTDs on the 'XML > > parsers running off to get stuff' front. > > I couldn't disagree more. It is a requirement on validating > parsers that the DTD be retrieved. It is not a requirement on > any existing piece of software that a representation of an XML > namespace be retrieved. What have requirements got to do with anything? There's no requirement that non-validating parsers retrieve DTDs, but some do (I believe that Suns/Crimson did at one time, maybe still does). Mutatis mutandis for namespace URIs and anything that might be hanging off the end of them. > > These aren't problems with either DTDs or namespace URIs per > > se. The problem is using a protocol (and, by extension, > > encoding that protocol in an identifier via a scheme) which > > doesn't support distribution and replication in a way which > > is appropriate for this kind of situation. > > The architecture of the Web, and the design of URIs and HTTP, > is meant to accomdate *exactly* this situation. What exactly > does HTTP not do that you need? Huh? If my client isn't configured to use a proxy (either directly or transparently) then if I try to retrieve, http://www.example.com/blah.dtd it goes off and hits www.example.com. What current, widely deployed, widely applicable, mechanism is there for redirecting that request elsewhere? Even if my client is configured to use a proxy, the proxy might not have that resource cached. By 'widely applicable', I mean a mechanism which can be applied to a 'hot' resource without the hosting site having to be radically rejigged (eg. wholesale delegation to a third party via DNS). > > You've mentioned an Akamai-type solutions to this problem. I > > don't see how that's supposed to help ... could you > > elaborate? > > Just that URL resolution (including HTTP URLs) need not ever > reach the origin server. More detail please ... Cheers, Miles -- Miles Sabin InterX Internet Systems Architect 5/6 Glenthorne Mews +44 (0)20 8817 4030 London, W6 0LJ, England msabin@interx.com http://www.interx.com/
Received on Monday, 5 February 2001 12:56:48 UTC