Re: [Visionaries] Vision of debugging webservices : Interceptors

[Norbert Bollow]

> > I doubt that the above suggestion is a good solution.

James Michael DuPont <address@hidden> relied:

> It is a very good solution.

Well, I disagree.  The "interceptor" idea requires adding complexity
to the VMs in an area where things should be kept as simple as
possible so that we can optimise for speed.  Also, from a security
perspective, it's bad news if you can't rely on method calls doing
exactly what the code says they should do.  A complicated security
model is a bad security model.

> > I'd rather suggest that there is a "data recording mode"
> > in which the webservice server logs all data that is necessary
> > for replaying exactly whatever the webservice program is doing.
> 
> That is only one function of many. We need way to filter out single
> calls and be able to display them graphically.

If you can replay exactly what the VM in the webservice server did,
you can do this on a "debugging VM" which does whatever you want.

My objection is not against providing the functionality that you
desire; rather I'm saying that the VMs in the webservice server are
not the right place for providing this functionality.

> > (This includes both data that is received via the network and also
> > copies of all database records that are retrieved by the webservice
> > program.)
> 
> That is easy to do, but the data is hard to use. You need ways to pick
> out and process individual records.

I don't agree with the statement "the data is hard to use".

Think of this as downloading a copy of the server's database (as it
was before the webservice ran) from which those records which are
known to be irrelevant have been removed.

Then you replay whatever the webservice did in your "debugging VM".

> I have worked with some xml rpcs stuff before, and they are hard to
> debug.  We need to have a framework for finding and intercepting single
> packages. We need way to send the packets to a gui on the client.

Yes, whatever "webservice debugger app" we build around the "debugging
VM" should provide this functionality.

(Note that until we have a mature webservices debugging system, this
webservice debugger app will be much easier to debug if it is *not*
a webservice app.)

Greetings, Norbert.

-- 
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