[JDEV] Jabber as Application Middleware

[Ralph Meijer]

I've been wondering about this too. One of the things I kind of miss is
queueing on the server for outgoing messages. In my situation you would have
several servers which need to communicate messages. It is not really important
when such a message arrives, but that it gets there eventually, is.
As I understand, the current situation is that jabber servers just return
an error when the other party is not reachable. The problem with this is that
the client is required to handle this exception, which I think should not
be the case.

Greetz,

Ralphm

On Mon, Mar 05, 2001 at 01:19:34PM -0600, eric at openthought.net wrote:
> Hello all,
> 
> I am interested in using Jabber as a sort of middleware for several
> applications at my place of work.
> 
> The details:
> Currently, we have two sets of programmers.  The first set develops
> applications in Foxpro and Visual Basic for in-house use.  The second develops
> applications in Perl and HTML for web use.
> 
> At first, the applications were all unique.  However, it has gotten to the
> point where both sets of develops are creating the same programs.  The only
> difference at all is the method it is viewed.  Before it becomes a game of cat
> and mouse trying to keep the programs the same, we need to find a way to reuse
> the code base.
> 
> The proposed solution:
> We would like to use some sort of middleware system where we can have a single
> backend for our applications (would object server be an appropriate term?), and
> two front ends to handle the visual part of the apps.
> 
> After exploring several different avenues, the Jabber project came to mind.
> And as two people can easily talk to each other, why not two applications?  The
> idea would be to have the 3 parts of these applications log in to the Jabber
> server (2 frontends + 1 backend).  An example of a front end might be a Perl
> script on a webserver.  A web based user might request a particular page
> containing some data that needs to be pulled out of a database.  The frontend
> -- routing through the Jabber server, queries a particular function on the
> backend, who would respond with the appropriate data.  In this case, querying a
> function means sending an IM to the JID the backend is logged in as.
> 
> My questions:
> 1. Is Jabber currently up to this type of usage?
> 
> 2. What protocol would be the recommended method of handling the style of query
> I mentioned?  Some ideas I had were embedding a CORBA message within the IM
> that the applications send to each other.  The same could probably be done with
> XML-RPC.  However, is there a method already in use for a task like this in
> Jabber?  And if not, is there a better method then CORBA/XML-RPC?
> 
> 3. Speed -- upon proposing a system like this, the first question my boss asked
> was what kind of performance hit were we going to take for having a distributed
> system.  The web based system isn't really the issue, it's the internal one.
> Currently, users are able to use their up and down arrow keys to scroll through
> a list of names.  Every time they hit the down arrow key, it grabs a list of
> data for that particular person from the database.. meaning every action they
> do requires a full round trip to and from the DB.  Since there are almost a
> million records, grabbing every entry at once isn't an option.  Is it a
> reasonable goal to expect every round trip to take under 500ms with Jabber, if
> it currently takes 100-200ms in it's stand-along form?  Purchasing hardware is
> not a problem -- we are perfectly willing to get gigabyte ethernet or whatever
> if it would make a difference.
> 
> 4. Just to have some comparisons, what are your opinions on why a system like
> this using Jabber would be better then something like Oracle Application
> Server, xmlBlaster, and other such products?  And if Jabber isn't the right
> tool here, what is?
> 
> 5. Are there any other projects out there that are trying to do anything like
> this?
> 
> Assuming we use Jabber, we'll be putting a lot of development effort into our
> apps.  I am intending on making at least some of what we develop open source,
> so we can get this stuff out into the community.  Maybe that'll inspire some
> people to assist in getting us pointed in the right direction :-)
> 
> I look forward to your opinions and insight.  Thanks!
>   -Eric
> 
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