[Juser] Question and answer service design
theo at jivatechnology.com
Mon Jun 29 08:41:58 CDT 2009
We are currently trying to develop a question and answer service using
XMPP, and are looking for some guidance - perhaps in the form of
consultancy or a workshop.
The idea is that a 'student' posts a question to a subject node, this
question is then sent out to various 'tutors' who are subscribed to
this node. When an appropriate tutor is found, the question is removed
from the node
This of course fits the Pubsub mechanism very nicely. However, the
'student' needs to see who is subscribed to the node, and who is
online. MUC seems to fit this problem nicely. Someone enters a room,
and then has access to other users presence, however MUC doesn't offer
the same type of adding and removing of items.
We are currently solving this problem by using two Pubsub trees. One
stores the subjects and has the questions as items. The other attempts
to represent which tutors are subscribed to what. For example:
pubsub n subjects
i How is Pi calculated?
i How do I calculate SD
i What is the speed of light?
i Charles Babbage
i Blaise Pascal
i Albert Einstein
i Albert Einstein
This is being maintained by a number of bots, but it doesn't take care
of presence information which is currently being handled by a shared
roster. This of course means all students receive the presence of all
tutors, which is unnecessary (a student who has a maths question does
not want the presence of a physics question). Multiple shared rosters
could overcome this, but it feels messy. It also puts complexity onto
the client, instead of packaging it up on the server.
Is it possible to do this using purely Pubsub, or are we asking too
much? It seems to me that a hybrid of MUC and Pubsub best fits this
problem, but that would carry of the overhead of coding up a
completely fresh solution for something where all the parts already
exist. How would you implement this?
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