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Yes folks, Python is truly a programmer's goldmine. Today we're going to do something Web 2.0-worthy with Python. We're going to create a server written in Python. But not just any old server. We're going to create an XML-RPC server, and we'll also write up a tiny client for it as well to demonstrate how surprisingly simple it is to build a server.

First, let's write up the server itself. Let's call this file "xmlrpc_server.py":

#!/usr/bin/env python

import SimpleXMLRPCServer
#set server address(local here)
servAddr=("localhost",8080)
#define server functions and instances here
def areaSquare(length):
        return length*length

def areaRectangle(length,width):
        return length*width

def areaCircle(radius):
        return 3.14*(radius*radius)

class MyFuncs:
        def say(self,line):
                return "#"+line+"#"

#create the server object
server=SimpleXMLRPCServer.SimpleXMLRPCServer(servAddr)
funclist=(areaSquare,areaRectangle,areaCircle)
#register functions
for eachfunc in funclist:
        server.register_function(eachfunc)
#register instance
server.register_instance(MyFuncs())
server.register_introspection_functions()
#start serving
server.serve_forever()

To start up this little server, type "python ./xmlrpc_server.py &" on the command-line. Now, let's write a little demo client to show that we can actually use the server. This file will be called "xmlrpc_client.py":

#!/usr/bin/env python

import xmlrpclib
#connect to a server
servAddr="http://localhost:8080"

s=xmlrpclib.ServerProxy(servAddr)
#list available server methods
for m in s.system.listMethods():
        print m
#call server methods
print "Areas:"
print "Square:",s.areaSquare(5)
print "Rectangle:",s.areaRectangle(2,6)
print "Circle:",s.areaCircle(5)
print s.say("E=m(c*c)")

Simply run "python ./xmlrpc_client.py", and you'll see that we are actually using functions stored remotely on the server. Pretty cool, right? No? Well, you haven't seen anything yet. You see, this XML-RPC stuff can be used within web services, which shockingly includes scripted objects within Second Life. With XML-RPC you can create objects networked together to do things that would be difficult, slow, or plain impossible to implement. I'll get more into this in my next post.