Re: XML Schema validation and https redirects

[ I’m aware that this discussion is drifting away from xmlschema-dev’s
  core mission, but as long as no one else minds, I guess I’ll press on. ]

Michael Kay <mike@saxonica.com> writes:
> What I don't understand is why ISPs or local proxy servers aren't
> caching such resources. But then, I'm like everyone else - I use a lot
> of technology that I don't fully understand.

Back in the day, when I first got interested in implementing a catalog
resolver, one of my friends argued that it was a bad idea. He didn’t
like them and didn’t think they provided a good, general purpose
solution.

His counter-proposal was that a local caching proxy should be
configured. That way, you could get all of the resources you wanted,
directly from the URIs published, but they’d only be fetched once from
the remote server. You’d get all the benefits of local resolution
without having to know about, and maintain, an XML catalog.

I tried, unsuccessfully to make this work. I know enough about
networking to be dangerous and I could not make it work. Beyond getting
the actual bit of caching software setup, installed, and configured so
that it would do “the right thing” with requests, would check for new
and updated resources at reasonable times, etc., you have to figure out
how to make each tool use the caching proxy. In principle, this isn’t
hard. In practice…bah humbug! I gave up.

And this was back in the day when we only had http: to worry about.
Today, if you wanted to make this work, you’d have to do something to
make the caching capable of dealing with SSL. It can’t just sniff the
request because that’s the whole point of https! I’m sure it can be
done, but I’m even more sure, it’s more complicated than I’m willing to
manage. And I’m fairly keen to manage complicated things if it makes
other things better.

Ironically, I went to a fair bit of effort to implement caching in XML
Resolver so that it would manage an XML catalog for you. And I’ve just
disabled it by default in 4.5.0 because enough people were uncomfortable
with the fact that it scribbled on the users filestore. Fair enough, but
now that it’s an option you have to enable, 99.95% of users will never
get the benefits it was intended to provide. C’est la vie.

                                        Be seeing you,
                                          norm

--
Norman Tovey-Walsh <ndw@nwalsh.com>
https://nwalsh.com/

> That which we call sin in others, is experiment for us.--Emerson