FAQs (Frequently Asked Questions)

What is XML-RPC and why is it useful?

It's a specification that defines how software running on disparate operating systems, in different environments can make procedure calls over a network(Internet or Intranet). XML-RPC uses HTTP for the transport layer, and defines an XML grammar for encoding data in a neutral way.

XML-RPC is important because it provides a simple, easy to use grammar and syntax for exchanging data and making remote procedure calls. Thus, XML-RPC provides a lightweight, minimalistic mechanism for engaging in a web services dialogue.

How does XML-RPC differ from SOAP?

SOAP is asynchronous, XML-RPC is not
SOAP supports request routing and pre-processing of requests via SOAP headers
XML-RPC is lighter, taking up less bandwith, and requiring less processing power
SOAP is namespace-aware (in fact every element must be namespace-qualified)
SOAP has a heavy-weight, robust data typing mechanism based on XML Schemas
XML-RPC is easily sent and consumed, and is easily readable by humans
SOAP messages have a considerable amount of packaging contained in the envelope, but this allows for flexibility in the messaging paradigm used (publish-subscribe, point-to-point, etc.)

When should I use kXML-RPC vs using kSOAP?

Use kXML-RPC when...

Speed is of greater importance than flexibility
Memory usage is a critical factor
Program size must be very small ( < 8kb )
The data being exchanged is simple, or at very least the relationships between the data are simple
You need a neutral, standardized, lightweight mechanism for exchanging data, or remotely invoking some network service

Use kSOAP when...

Flexibility and a robust feature-set are a high priority
Program size and memory usage are less important than advanced networking features
The data being exchanged is complicated, the relationships between the data are complicated, or is it important to define custom data types
If you are uncertain which protocol will be used by potential clients and partners (SOAP is more popular, and thus a better bet in an uncertain situation)