[Twisted-Python] Spread or SOAP

[Sam Couter]

David Ripton <dripton at ripton.net> wrote:
> If you like the basic idea of SOAP (client/server RPC via XML over http), 
> I think XML-RPC (which is basically an early draft of SOAP) is fine.
> Then feeping creaturism set in, and SOAP (plus the ring of associated
> cruft like WSDL) is no longer simple.

WSDL is one of the very few redeeming features of SOAP - it's the
equivalent of CORBA's IDL, and allows you to define an interface and what
types it expects. For languages less dynamic than python, the WSDL can be
used to generate stub and skeleton code in an automated fashion.

Without WSDL, that code has to be written by hand. That's a menial, error
prone and BORING task. Other RPC systems worked out not to do that
decades ago.

For languages as dynamic as python, it allows code to dynamically
interrogate an interface to find what functions it provides.

> If pure request-response with just basic types is all you need, then 
> either will work fine.  (So will SOAP, or CORBA for that matter if 
> firewalls don't preclude it -- there'll just be more docs to read.)

Both SOAP and CORBA allow you to define complex objects to be marshalled
over the wire. Neither are limited to simple types. CORBA is not limited
to simple request-response.

With CORBA the remote end can get a stub (object reference) that they can
call remote methods on (callbacks). Object references can be passed back
and forth all over the place, and the stub knows where to send the
callback requests to find the original implementation of that object.

SOAP is value-object (structured data, no methods) only.

As far as I can tell, PB is a python-only equivalent to CORBA.
-- 
Sam "Eddie" Couter  |  mailto:sam at couter.dropbear.id.au
Debian Developer    |  mailto:eddie at debian.org
                    |  jabber:sam at teknohaus.dyndns.org
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