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Starting out with web services for Python

One of the things that I’ve been looking at is web services. So far, I’ve played around with .NET, Java (Axis) and PHP for writing and consuming them, however I wanted to be able to at least access them from Python.

A quick web search didn’t unearth a site which covered everything I was interested in, so a bit more digging was required. The following resources I’ve found useful so far:

For now, I’m going to try out SOAPpy as it seems simpler. However, ZSI appears to have better support for complex types in WSDL. Complex types being the feature that tends to limit most WSDL tools.

As an example, here is a simple server:

import SOAPpy
import os

def systemInfo():
    return os.uname()

server = SOAPpy.SOAPServer(('localhost', 8080))

The client is as easy as:

>>> import SOAPpy
>>> proxy = SOAPpy.SOAPProxy('http://localhost:8080/')
>>> proxy.systemInfo()[0]

os.uname() returns an array of data, which is encoded into XML by the server, and then decoded back into a Python array in the client. On the wire, the actual data looks like:

  <systemInfoResponse SOAP-ENC:root="1">
  <Result SOAP-ENC:arrayType="xsd:string[5]" xsi:type="SOAP-ENC:Array">
    <item>Darwin Kernel Version 8.1.0: Tue May 10 18:16:08 PDT 2005;root:xnu-792.1.5.obj~4/RELEASE_PPC</item>
    <item>Power Macintosh</item>

Dive into Python has further information on how to obtain debugging information, as well as an example of performing a Google search.