The Objective-C language is an object-oriented language derived from C with late binding and a rich runtime. XML-RPC is a distributed object protocol similar to SOAP. PADL have developed a bridge between these two technologies, allowing Objective-C applications to transparently access XML-RPC servers, and such servers to be written in Objective-C itself.
The bridge is divided into two parts: XMLRPCObjC, which handles method translation and other runtime-agnostic tasks; and XMLRPCGlue, which is presently a thin layer between XMLRPCObjC and the xmlrpc-c library. The latter could be replaced with a library that used the XML parser and HTTP client in Foundation.
A Mac OS X system. We depend on private Foundation API; other implementations of Foundation may not work
The xmlrpc-c library. This is available from http://xmlrpc-c.sourceforge.net/. We submitted some patches which should have been integrated into the current release.
This will invoke the XMLRPC method "sample.add" on the URL http://localhost:8000/RPC2. (You need to declare the add:: method somewhere so the compile will find it, but it's not necessary to register this with the XMLRPCObjC runtime if your XMLRPC server supports type introspection.)
We put together a simple Mac OS X client for O'Reilly's Meerkat wire service in about five hours, with little prior Cocoa programming experience. Articles may be opened in the default web browser. See the screenshot below: