From: mitra@path.net (Mitra)
Subject: Re: URLs, URIs, and references
Date: Wed, 26 May 1993 03:18:01 GMT
Message-Id: <C7M6I5.4tB@pandora.sf.ca.us>
I'll leave the quiz to others - I tried to use URL's on a project I'm
working on, a caching, proxy gopher server to sit on a firewall, or at
the end of a slow link.
I hit several problems that others have done.
1) A need for a clear mapping between URL's and selectors for different
protocols i.e. the server wants to hold URL's internally and pass them
to other cooperating servers, but needs to talk Gopher Selector's to the
rest of the world. I had to reinvent this, and my please for the
existing WWW <-> Gopher mapping elicited no response.
2) Lack of typing - I am NOT advocating incorporating typing into URL's
or URN's, but we need to come up with a format for combining a URL with
this information real quick if people are to be able to throw together
some systems to test this. A URL on it's own is almost useless, for
example in the Gopher environment, there is no way to tell whether a
selector requires a search string appended before sending back to the
requester.
3) The character mapping problem. I decided against mapping selector
strings to %xx coding for internal use, I'll escape out the illegal
characters when and if I have to communicate URL's to a system which I
dont know can support them. The more I think about this, the more
bizarre the rules seem to be. If the URL is intended for a machine to
read, it can incorporate any binary representation. If we pass it
through a mechanism that cant handle some characters then that is where we
should encode and decode it. If WWW doesnt like spaces in URL's then let
WWW code them internally without a %xx coding, but present to the users
as a real ascii (not neccessarilly US ASCII) string.
My final worry doesn't come from experimenting, and that is a very real
worry that we shouldnt finesse too much to URN's, there is a very real
speed problem in looking up URN's and I would need a lot of convincing
that a fast enough system can be put together to allow the use of URN's
for any kind of short-term storage of a pointer. For doing an archie
style lookup then a delay of 30 seconds or so may be acceptable, but
when following a hyper-text or gopher link a delay of 1 second or more
is perceived as slow.
- Mitra