[Twisted-Python] Multicast XMLRPC

Chaz. eprparadocs at gmail.com
Thu Aug 24 15:13:35 EDT 2006

Itamar Shtull-Trauring wrote:
> On Thu, 2006-08-24 at 14:13 -0400, Chaz. wrote:
>> There is a problem with this approach - that is the semantics of the 
>> call. Current RPC calls are EXACTLY ONCE semantics - it either works or 
>> doesn't. In this there is an uncertainty - it might have worked and I 
>> don't know about it (the response was lost for instance) or the server 
>> itself failed and restarted. This means I can't every be guaranteed the 
>> normal call semantics. It means it switches to AT LEAST ONCE semantics. 
>>   This means I have to be careful in how I code the server side.
> If your protocol has a unique message identifier you can make sure
> duplicate commands are not rerun.
I thought about doing that but ruled it out. So long as the server runs 
I can count on the UID being stepped correctly. If the server goes down 
and comes back up, it might be reset or set incorrectly.  So I can't 
guarantee it. Can you see another way around the problem?


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