SOAP Methods

The External SOAP Method product provides support for external SOAP methods, exposing them as callable objects within the Zope environment.

This is a blatant hack of ExternalMethod to not use a .py file but use the SOAPpy library instead.

Due to their nature SOAP methods can take a long time to execute or not return at all if the remote server is unresponsive. Therefore an optimization technique available to you is to cache the results. We have made SOAPMethod cacheable with RAMCacheManager. Note that RAMCacheManager adds the AUTHENTICATED_USER as an extra key to the cache. Since AUTHENTICATED_USER is not used by SOAPMethod it is redundant.

Dependencies

A module called SOAPpy, which can be downloaded from Python Web Services SOAPMethod is tested with SOAPpy-0.10.1

PyXML from Sourceforge SOAPMethod is tested with PyXML-0.8.2.

Both these packages use python setup.py build/install. If you use the binary installation of Zope then just use the python executable that comes with Zope to put it in site-packages.

Example

Id

getQuote

Endpoint Url

http://services.xmethods.com/soap

Method

getQuote

Namespace

urn:xmethods-delayed-quotes

Then call this from a DTML Method as <dtml-var "getQuote(symbol=IBM)">

Interoperability

SOAP is a relatively young standard. SOAPpy and some of the services are immature. During development we discovered for instance that the babelfish service returns strings in UTF-8 encoding. SOAPpy tries to convert the result to US-ASCII and will fail if there are characters with the 8th bit set. You therefore must manually change the encoding with

<dtml-var "babelfish(translationmode=en_fr,sourcedata=source).encode(latin-1)">

We could have done this in SOAPMethod, but we don't know what character set you use in your webserver.

Another interoperability issue is the support of certain popular but non-standard encodings of data structures. Data structures that are natural to use from Java, but SOAPpy simply doesn't support. E.g. the xsi:type is "ns2:Vector". The namespace is "http://xml.apache.org/xml-soap" and this is not in the SOAP 1.2 specifications.

References

XMethods a registry of public SOAP methods

Java SOAP server using Apache BeanSerializer

SOAPBuilder's Interoperability Meeting

Apache SOAP type mapping

Credits

Georg Bauer from GWS wrote the first version of SOAPMethod in 2001.