Getting started, part 2

In this tutorial we’re going to introduce WSDL and send a couple of requests using a SOAP client. It is based on the previous one, so you’d better walk through it, if you hadn’t before.

Introducing WSDL

Ok, if you are intereseted in SOAP you might have already heard about WSDL and what it is. If you hadn’t then it’s the most wonderful thing about SOAP, it is a language which may be used to provide a formal specification of a SOAP web service. This specification can be used to generate clients which can easily interact with a server taking away all the burden of making and sending requests from your shoulders.

Having our pyws server running on localhost:8000 and bound to /api/ we can get it’s WSDL description at http://localhost:8000/api/wsdl. You may want to cast a glance on it, but it isn’t necessary.

Now, let’s create a client and send a few requests. We will use suds, it is written in Python and is quite pretty to use. Open python console and let’s write some code there:

>>> import suds
>>> client = suds.client.Client('http://localhost:8000/api/wsdl', cache=None)
>>> client.service.add_simple('hello ', 'world')
hello world

That’s it! Isn’t it awesome? No curl, HTTP, POST and so on, we just call a method and it just works!

Complex types

Now it’s time to play with some comlex types: lists and dicts.

First, we need to add a couple of functions to the server, again edit server.py, add this:

@register(return_type=[int], args=([int], ))
def double_list(a):
    return map(lambda x: x * 2, a)

ABDict = {0: 'ABDict', 'a': int, 'b': int}

@register(return_type=ABDict, args=(ABDict, ))
def double_dict(a):
    return dict((k, v * 2) for k, v in a.iteritems())

The code seems to be quite self-explanatory, the only thing is that 0: 'ABDict' gives the dict a name, it’s required as pyws can’t just invent it. Now, restart the server and go back to python console:

>>> import suds
>>> client = suds.client.Client('http://localhost:8000/api/wsdl', cache=None)
>>> lst = client.factory.create('ns0:IntegerList')
>>> lst.item = range(3)
>>> client.service.double_list(lst)
(IntegerList){
   item[] =
      0,
      2,
      4,
 }

>>> dct = client.factory.create('ns0:ABDict')
>>> dct.a = 1
>>> dct.b = 2
>>> client.service.double_dict(dct)
(ABDict){
   a = 2
   b = 4
 }

Pretty simple, huh?

Now that you’ve done with this introduction, you may want to go deeper.