python and SOAP??

[Duncan Grisby]

In article <zImT7.6877$PA.5509 at atlpnn01.usenetserver.com>,
 Steve Holden <sholden at holdenweb.com> wrote:

>"John Thingstad" <john.thingstad at chello.no> wrote ...
>> I feel the need to spesify that SOAP is a protocol created to send Object
>transcripts over the HTTP protocol.
>> CORBA however existes for objects to communicate over the lLAN.
>> CORBA (or for that matter DCOM) must be fast as it is created to allow a
>cluster of objects distributed over multiple machines to exchange date.
>
>I am not a CORBA expert, but I don't see anything in the protocols that
>wouldn't work over the wide area, and I believe it has been used in this
>way.

Indeed. CORBA works fine in the wide area. See this, for example

  http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/81254

To export the public server on spud.uk.research.att.com, I just had to
convince our sysadmins to open the right port on the firewall.


>> SOAP works as a much higher level of abstartion. Say communication
>> with a bank.  Further CORBA will usually be blocked from internet
>> accesss. SOAP using HTTP protocol will not.
>
>Indeed, although given that firewalls are normally installed precisely to
>PREVENT the kind of thing you can do with SOAP one wonders how long this
>state of affairs is likely to last. I have alsways felt that this aspect of
>SOAP's justification was pretty bogus.

I think so too. Tunnelling everything through a port that's normally
used for "safe" things like web servers is not a proper, secure,
solution. This is a good discussion of using HTTP for other protocols:

  http://www.ietf.org/internet-drafts/draft-moore-using-http-01.txt


The main problem with CORBA and firewalls is actually not in
convincing the powers-that-be to open a port for the server, it's that
you often want to use callback objects, where the server opens a
connection back to the client. CORBA has solved this problem to an
extent with bi-directional connections, where the same TCP connection
used for the outgoing call is used for the callback. That can only
work if the client keeps its connection open, of course, so it's not a
complete solution.

SOAP (and XML-RPC, etc) avoids this problem by not supporting callback
objects at all. That can hardly be seen as an advantage.

Cheers,

Duncan.

-- 
 -- Duncan Grisby  \  Research Engineer  --
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