[DAS2] proxies, caching and network configuration

[Andrew Dalke]

I'm writing to encourage DAS client authors to include
support for proxies when fetching DAS URLs.

Nomi pointed out that Apollo supports proxies, because
users asked for it.  I think it's because some sites
don't have direct access to the internet.  I know a few
of my clients have internal networks set up that way.

Yesterday we talked a bit about how to point to local
mirrors.  It would be hard to have a standard configuration
so that all DAS client code can know about local mirrors.
I mentioned setting up proxies, but dismissed the idea.

Now I'm thinking that that might be the solution.  If
there are local ways to get, say, sequence data then
that could be done at the proxy level.  Someone can easily
(with less than 100 lines of code) write a new proxy
server which points to a local resource if it knows that
a URI is resolvable that way.

Having proxy support also helps with debugging, like in
the debugging proxy server I wrote yesterday.

A nice thing is that some people want proxy support
anyway, so if client code supports proxies then these
other things (redirection to local mirrors, debugging)
can be set up later, and with no extra work in the client.

					Andrew
					dalke at dalkescientific.com