Following subsections deal with the description of mechanisms for extracting technical information regarding service functionality from various documentation sources: WSDL descriptors for SOAP services, and HTML documents for XML-RPC and REST services.
XML-RPC and REST services are commonly described by HTML pages, which provide information regarding service functionality and endpoints (1).
This way, we apply on each HTML page an analysis that involves identifying recurring patterns (which depends on the service type, either XML-RPC or REST) and document segmentation for extracting relevant information regarding service functionality.
Although SOAP (He, 2003) is more frequently used to transmit remote procedure calls, XML-RPC has the advantage to produce less data traffic overhead.
* A simple yet powerful communication protocol: XML-RPC engages remote procedure calls coded in XML and transmitted as HTTP requests.
The CYCLADES environment provides utmost flexibility by simple and clear regulations--concerning the technical communication among the components via XML-RPC. It also shows that--although SOAP is widely propagated as the best solution for service-oriented architectures (He, 2003)--XML-RPC also has its strengths.
The presentation server requests and receives data from the application server, using a variety of techniques including stateful protocols such as RMI/JNDI/IIOP in Java, or stateless protocols such as HTTP, with or without some XML based protocol such as SOAP or
XML-RPC.
XML expert Tim Bray, a co-editor of the World Wide Web Consortium (W3C) XML Specification, says of XML-RPC: "Obviously it is immensely simpler than Corba and obviously for the same reasons, it does less for you.
"If you just need to get something simple and straightforward running in a couple of weeks, that might be a job for XML-RPC." OMG's VP of technology Andrew Watson is less sanguine about XML-RPC.