XML-RPC

NOTE: All credit for this code goes to Crast in irc.freenode.net:#django...

This uses SimpleXMLRPCDispatcher which is part of the standard Python lib in 2.4 (And possibly earlier versions).

In discussing ways of handling XML-RPC for Django, I realised I really needed a way to do it without patching Django's code. Crast in #django came up with a great solution, which I have modified and tweaked a bit.

I've included it here. Feel free to fiddle with it and make it your own ... All this code is post-mr

Any crappy & garbage code is completely mine; I'm still learning Python so bear with me. The hacks I added for self-documentation output are just that; any improvements to them would probably be a good thing.

First, setup your urls.py to map an XML-RPC service:

urlpatterns = patterns('',
    # XML-RPC
     (r'^xml_rpc_srv/', 'yourproject.yourapp.xmlrpc.rpc_handler'),
)

Then, in the appropriate place, create a file called xmlrpc.py

# Patchless XMLRPC Service for Django
# Kind of hacky, and stolen from Crast on irc.freenode.net:#django
# Self documents as well, so if you call it from outside of an XML-RPC Client
# it tells you about itself and its methods
#
# Brendan W. McAdams <brendan.mcadams@thewintergrp.com>

# SimpleXMLRPCDispatcher lets us register xml-rpc calls w/o
# running a full XMLRPC Server.  It's up to us to dispatch data

from SimpleXMLRPCServer import SimpleXMLRPCDispatcher
from django.http import HttpResponse

# Create a Dispatcher; this handles the calls and translates info to function maps
#dispatcher = SimpleXMLRPCDispatcher() # Python 2.4
dispatcher = SimpleXMLRPCDispatcher(allow_none=False, encoding=None) # Python 2.5


def rpc_handler(request):
        """
        the actual handler:
        if you setup your urls.py properly, all calls to the xml-rpc service
        should be routed through here.
        If post data is defined, it assumes it's XML-RPC and tries to process as such
        Empty post assumes you're viewing from a browser and tells you about the service.
        """

        response = HttpResponse()
        if len(request.POST):
                response.write(dispatcher._marshaled_dispatch(request.raw_post_data))
        else:
                response.write("<b>This is an XML-RPC Service.</b><br>")
                response.write("You need to invoke it using an XML-RPC Client!<br>")
                response.write("The following methods are available:<ul>")
                methods = dispatcher.system_listMethods()

                for method in methods:
                        # right now, my version of SimpleXMLRPCDispatcher always
                        # returns "signatures not supported"... :(
                        # but, in an ideal world it will tell users what args are expected
                        sig = dispatcher.system_methodSignature(method)

                        # this just reads your docblock, so fill it in!
                        help =  dispatcher.system_methodHelp(method)

                        response.write("<li><b>%s</b>: [%s] %s" % (method, sig, help))

                response.write("</ul>")
                response.write('<a href="http://www.djangoproject.com/"> <img src="http://media.djangoproject.com/img/badges/djangomade124x25_grey.gif" border="0" alt="Made with Django." title="Made with Django."></a>')

        response['Content-length'] = str(len(response.content))
        return response

def multiply(a, b):
        """
        Multiplication is fun!
        Takes two arguments, which are multiplied together.
        Returns the result of the multiplication!
        """
        return a*b

# you have to manually register all functions that are xml-rpc-able with the dispatcher
# the dispatcher then maps the args down.
# The first argument is the actual method, the second is what to call it from the XML-RPC side...
dispatcher.register_function(multiply, 'multiply')

That's it!

You can pretty much write a standard python function in there, just be sure to register it with the dispatcher when you're done.

Here's a quick and dirty client example for testing:

import sys
import xmlrpclib
rpc_srv = xmlrpclib.ServerProxy("http://localhost:8000/xml_rpc_srv/")
result = rpc_srv.multiply( int(sys.argv[1]), int(sys.argv[2]))
print "%d * %d = %d" % (sys.argv[1], sys.argv[2], result)

Based on experience, I do recommend that you use Dictionaries for your args rather than long args, but I think that's personal preference (It allows named arguments and eliminates 'out of order' argument issues).

Have fun!

• Brendan W. McAdams

---

I wrote up ​a modified version of the XML-RPC view that uses a template for documentation. -- Adam Blinkinsop