URLs in web-based groupware

I am involved in an EU-funded research project (Senior
Online, http://cmc.dsv.su.se/sol) which has decided to
develop a protocol for communicating between
non-simultaneous forum systems (like Lotus Notes, First
Class, etc.). We have noted that many such forums are
web-based or have a web-based user interface. By web-based
is meant that the users use an ordinary web browser as a
client, and that many of the normal functions of a client
is handled by the HTTP server.

We have, however, noted a technical problem, which we would
like to have guidance from experienced application-layer
protocol designers on. The technical problem is as follows:

A user should be able to participate in different forums,
which are hosted by different forum servers, connected
through the protocol we develop. The user, however, will
prefer to connect to only one of these servers. There are
many reasons for this:

(a) The user wants the same user interface for all forums.

(b) A facility for ordering and prioritizing new messages
    and forums is easier provided to users if they always
    access one server.

(c) The user need not log in multiple times, if only one
    server is used.

Since ordinary web browsers are used as clients, forums and
messages in forums and other group communication objects
should all have URLs. However, the URL of a group
communication object must vary from user to user, since it
must start with the domain name of the server which each
particular user is using.

For example, assume that there is a forum named
"tropical-flowers". The URL of this forum may be
 http://sol.botany.com/tropical-flowers. If, however, I am a
user of the groupware server at http://sol.myhome.se, then
the URL of the forum must start with http://sol.myhome.se.
If its URL was http://sol.botany.com/tropical-flowers, then
clicking on it with an ordinary web browser would connect
me to a foreign groupware server, which is not wanted.

A possible solution to this problem might be to include the
groupware server domain twice, first the user's server,
then the groupware object's server. For example, if my
local groupware server is http://sol.myhome.se, then the
URL for the forum in the example above might be
 http://sol.myhone.se/sol.botany.com/tropical-flowers.

Variants of this solution:

(i) Put "?" between the domains, thus use
 http://sol.myhone.se?sol.botany.com/tropical-flowers
Disadvantage: Some web browsers use the same cached object
for all URLs with the same string before the first "?" in
the URL.

(ii) Put "/x" or "/external" between them, thus use
 http://sol.myhone.se/external/sol.botany.com/tropical-flowers

(iii) Require that the domain is repeated twice also when
connecting to the home server of the groupware object, in
the example above
 http://sol.botany.com/sol.botany.com/tropical-flowers

Question: Is this a good idea, and if so, which of the
three syntactical variants (i), (ii) and (iii) is best?

Note: Do not answer that we should use URNs. We cannot,
since web browsers do not at present support them.

A problem will of course occur, if a user sends by e-mail,
or puts in an ordinary web page, an URL like
 http://sol.other.com/sol.botany.com/tropical-flowers
and a user clicks on it. The user will then be connected to
 http://sol.other.com. Our intention is to solve this, by
having the welcome page of http://sol.other.com include
tools for the user to move to his home groupware server,
and access the same groupware object from that server.

------------------------------------------------------------------------
Jacob Palme <jpalme@dsv.su.se> (Stockholm University and KTH)
for more info see URL: http://www.dsv.su.se/~jpalme

Received on Sunday, 14 February 1999 14:44:44 UTC