URN resolver

Dear All,
It looks like we will have a URN resolver of ftp requests in this fall
(at least we promised that :-)). For information about it see
http://squid.itep.ru/.

I was looking at the URN support inside the squid and I find it not
working as I'd like. Here is extract from my letter to Alex Rousskov who
seems the only person on squid-users mailing list who was interested in
this:

> I looked at the current implementation (well not thoroughly) and I have
> a couple of suggestions. Wouldn't it be wise to include following
> additions in Squid configuration file:
>
> a) urn_resolver (so that admin can point to the local mirror tracker
> site)
> b) urn_prefered_domains (so that it will be possible to choose from
> different domains if nothing is available in the local one)
>
>
> The next thing I'd like to discuss is the way information is returned to
> the squid server. Right now we don't have a 100% foolproof method of
> locating mirror sites and there are at least two parameters. See the
> same urn resolution by the special script
>
> http://squid.itep.ru/uri-res/resolve2?url=ftp://ftp.rge.com/pub/X/XFree86/3.3.2/binaries/FreeBSD-2.2.x/Servers
>
> We were forced to use "Exact hits" and "Time blind hits" (sometimes
> timestamps are shifted on the ftp mirrors but file sizes are the same).
>
> It is also happens that in different directories there are files named
> the same, with the same timestamps and sizes, that's why we put that
> "probability" parameter.
>
> Can it be made so, that the squid will just show the text returned by
> the "Mirror Tracker" ? Surely in such a way one have to modify the
> returned content so that it will be possible to include information on
> the state of the object in cache.
>
> User may also want to reach the original content but it is impossible
> with the current implementation of the squid. Probably it can be nice to
> include some flag, so that there will be no resolution ?

I think that one can do the following thing. If there is a urn_resolver
in the squid.conf squid internally move all requests (all ftp requests)
to the URN resolver, then resolver is returning an HTML document with
the original URL on the top marked with some special flag that will
prevent future URL-URN-URL resolution (just like I'v done with the
redirector scripts)). The content of the document is also modified to
include state of the object in the cache and ping time (if pinger is
installed). If it was impossible to find a nearest mirror then original
URL is returned with don't-resolve flag.

                Alexei.
Received on Tue Jul 29 2003 - 13:15:59 MDT