Defining the principles of the World Wide Web

As soon as computers were networked, people created binary protocols to execute code on a remote computer. The disadvantage of these Remote Procedure Call (RPC) protocols is the system dependency. Due to the binary nature, it is not easy to get a remote procedure call right: the size of data types, endianness, and alignment may be different on the target machine. With the success of the WWW, the idea of services appeared. A service provides some functionality, for example, retrieving the stock price at NASDAQ in real time. Simple Object Access Protocol (SOAP) was created. SOAP is based on XML and, therefore, enables structured data exchange in heterogeneous networks. Web Service Description Language (WSDL) was created to describe the services, again in XML.

The combination of SOAP and WSDL is used to look up services and generate language bindings for them. This works very well, but there are drawbacks. SOAP is designed to be independent of the...