I'm looking for ways to accomplish this. Basically, we'd have, for some transition period, two sites that should appear seemless from a user standpoint. However, I'm willing for OpenACS to listen to another port.
I already have a user database of course (in OpenLDAP) in the older system.
There are too many variables to lay it all out here, so I'm just looking for some thoughts, ideas, direction, etc.
One question I have is whether I should try to get OpenACS to use the OpenLDAP user base directly, or just replicate changes into Postgresql for OpenACS to use. Replication is probably cleaner and easier to implement (I don't have Oracle, so I would have to port the LDAP package to use Postgresql in some way -- the package currently relies on Oracle's ability to access LDAP).
Another thing that would be highly desireable is single login -- authentication on one side would be recognized by the other. I can force users to hit my old site first. Would it just be a matter of setting some cookies to make OpenACS happy?