Parsing a SOAP response in Python

Question

I'm trying to parse a SOAP response from a server. I'm 100% new to SOAP and pretty new to communicating using HTTP / HTTPS . I'm using Python 2.7 on Ubuntu 12.04.

It looks like SOAP is very much like XML . However, I seem to be unable to parse it as such. I've tried to use ElementTree but keep getting errors. From searches I've been able to conclude that there may be issues with the SOAP tags. (I could be way off here...let me know if I am.)

So, here is an example of the SOAP message I have and what I'm trying to do to parse it (this is an actual server response from Link Point Gateway, in case that's relevant).

import xml.etree.ElementTree as ET
soap_string = '<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"><SOAP-ENV:Body><fdggwsapi:FDGGWSApiOrderResponse xmlns:fdggwsapi="http://secure.linkpt.net/fdggwsapi/schemas_us/fdggwsapi"><fdggwsapi:CommercialServiceProvider/><fdggwsapi:TransactionTime>Wed Jul 25 10:26:40 2012</fdggwsapi:TransactionTime><fdggwsapi:TransactionID/><fdggwsapi:ProcessorReferenceNumber/><fdggwsapi:ProcessorResponseMessage/><fdggwsapi:ErrorMessage>SGS-002303: Invalid credit card number.</fdggwsapi:ErrorMessage><fdggwsapi:OrderId>1</fdggwsapi:OrderId><fdggwsapi:ApprovalCode/><fdggwsapi:AVSResponse/><fdggwsapi:TDate/><fdggwsapi:TransactionResult>FAILED</fdggwsapi:TransactionResult><fdggwsapi:ProcessorResponseCode/><fdggwsapi:ProcessorApprovalCode/><fdggwsapi:CalculatedTax/><fdggwsapi:CalculatedShipping/><fdggwsapi:TransactionScore/><fdggwsapi:FraudAction/><fdggwsapi:AuthenticationResponseCode/></fdggwsapi:FDGGWSApiOrderResponse></SOAP-ENV:Body></SOAP-ENV:Envelope>'
targetTree = ET.fromstring(soap_string)

This yields the following error:

unbound prefix: line 1, column 0

From another stackoverflow post I've concluded that SOAP-ENV:Body may be causing a namespace problem. (I could be wrong.)

I've done other searches to find a good solution for parsing SOAP but most of them are from 3+ years ago. It seems that suds is pretty highly recommended. I wanted to get "updated" recommendations before I got too far down a path.

Can anyone recommend a solid (and easy) way to parse a SOAP response like the one I received above? It would be appreciated if you could provide a simple example to get me started (as I said above, I'm completely new to SOAP ).

Answer 1

I was unable to find a straight-forward approach using Python. I decided to use PHP instead.

Much like the following:

Python:

import subprocess
command = 'php /path/to/script.php "{1}"'.format(soap_string)
process = subprocess.Popen(command, shell = True, stderr = subprocess.PIPE, stdout = subprocess.PIPE)
process.wait()
output = process.communicate()[0]
(error, result, order_id) = output.split(',')

PHP:

#!/usr/bin/php
<?php

$soap_response = $argv[1];

$doc = simplexml_load_string($soap_response);
$doc->registerXPathNamespace('fdggwsapi', 'http://secure.linkpt.net/fdggwsapi/schemas_us/fdggwsapi');
$nodes = $doc->xpath('//fdggwsapi:FDGGWSApiOrderResponse/fdggwsapi:ErrorMessage');
$error = strval($nodes[0]);

$nodes = $doc->xpath('//fdggwsapi:FDGGWSApiOrderResponse/fdggwsapi:TransactionResult');
$result = strval($nodes[0]);

$nodes = $doc->xpath('//fdggwsapi:FDGGWSApiOrderResponse/fdggwsapi:OrderId');
$order_id = strval($nodes[0]);

$array = array($error, $result, $order_id);
$response = implode(',', $array);

echo $response;

This code only parses specific aspects of this particular SOAP response. It should be enough to get you going to solve your problem.

I'm a complete newbie when it comes to PHP (I've used Perl a bit so that helped). I must give credit to @scoffey for his solution to parsing SOAP in a way that finally made sense to me.

Answer 2

EDITED: Working with SOAP in Python is really fun - most tools are not maintained for years. If we talk about features - maybe ZSI is the leader. But it has lots of bugs if it comes to support some more complex XSD schemas(just one example - it doesn't support unions and complex types based on extensions, where the extended type is not a base type). Suds is very easy to use, but not so powerful as ZSI - it has worse support for some complex XSD constructs than ZSI. There is an interesting tool - generateDS , which works with XSD and not directly with WSDL - you have to implement the methods yourself. But it does a pretty good job actually.