Redirect loops and mazes

[solderpunk]

> Thanks Sean, this is great.

It is, indeed, thanks very much.  Happily, my AV-98 code worked as
expected without any changes.
 
> >   I suspect that most would expect the client to stop making requests after
> > N redirects.  What's N?  That hasn't been decided yet.

I decided to set N to 5 for now, and was happily surprised to see at
your test page that this very value was also (once) recommended for the
same purpose in HTTP via an RFC.  If nobody wants to argue strongly for
a higher/lower value, I will recommend 5 in the new "best practices"
document - this is exactly the kind of thing that I imagined that
document being good for.
 
> In addition to a redirect threshold, it's of course also easy for
> clients to keep track of the addresses seen during a redirect sequence,
> in which case they can just abort on a redirect to a seen address.

AV-98 does precisely this, too.

-Solderpunk