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<TITLE>RPC design questions</TITLE>
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<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:11pt'>I'm currently making some light-weight RPC/PubSub over WebSockets<BR>
using Twisted.<BR>
<BR>
I have two design-like questions where I'd be happy for advice/options ...<BR>
<BR>
The first is definitely Twisted related, the second not strictly, ..<BR>
<BR>
Tobias<BR>
<BR>
<BR>
1)<BR>
I'd like to chain RPC calls, i.e.<BR>
<BR>
self.call(23, "square").addCallback(self.call, "sqrt").addCallback(self.show)<BR>
<BR>
<a href="https://github.com/oberstet/Autobahn/blob/dev-rpc/demo/rpc/simple/simple_client.py">https://github.com/oberstet/Autobahn/blob/dev-rpc/demo/rpc/simple/simple_client.py</a><BR>
<BR>
self.call(<arg>, <procedure>) will return a deferred, <arg> is the marshalled argument<BR>
for the RPC, and <procedure> is the remote procedure identifier.<BR>
<BR>
Now, the nice thing is, I can chain the result from one call to the next like in the<BR>
example above.<BR>
<BR>
What I find less nice is that I have to have that order : <arg>, <procedure><BR>
since the result of the first deferred will be passed as the first argument to<BR>
the second, and only then will the additional arguments be passed (in above<BR>
example the "sqrt")<BR>
<BR>
How can I retain the - which I find - natural order for arguments?<BR>
<BR>
self.call(<procedure>, <arg>) <BR>
self.call("square", 6).addCallback(self.call, "sqrt").addCallback(self.show)<BR>
<BR>
=> not working, the 2nd self.call receives 36, "sqrt" ..<BR>
<BR>
<BR>
2)<BR>
The server side methods a hooked up using decorators, like<BR>
<BR>
class SimpleServerProtocol(AutobahnServerProtocol):<BR>
<BR>
@AutobahnRpc<BR>
def square(self, arg):<BR>
return arg * arg<BR>
<BR>
<BR>
<a href="https://github.com/oberstet/Autobahn/blob/dev-rpc/demo/rpc/simple/simple_server.py">https://github.com/oberstet/Autobahn/blob/dev-rpc/demo/rpc/simple/simple_server.py</a><BR>
<BR>
Here, AutobahnServerProtocol derives (indirectly) from Twisted Protocol.<BR>
<BR>
The decorator will register the method for RPC under "square".<BR>
<BR>
<a href="https://github.com/oberstet/Autobahn/blob/dev-rpc/lib/python/autobahn/autobahn.py">https://github.com/oberstet/Autobahn/blob/dev-rpc/lib/python/autobahn/autobahn.py</a><BR>
<BR>
That is all nice and simple, however I am wondering if it's a good idea to<BR>
do that auto-registering on a Protocol derived class.<BR>
<BR>
I mean, the alternative could be having the user call something like<BR>
<BR>
registerRpcObject(<any class instance with RPC decorators>, <base URI>)<BR>
<BR>
in Protocol.connectionMade(), which then would auto-register all decorated<BR>
methods in <any class instance ..><BR>
<BR>
What do you think would be better?<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
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