SOAP Message Structure

• Figure 4.11 illustrates the structure of a SOAP message, consisting of three parts:

• The SOAP Envelope: The outermost element of a SOAP message. The Envelope element is the root of the XML document that defines a SOAP message.

• The SOAP Header: The Header element provides a modular way of directing SOAP servers to do processing before passing the SOAP message on.

• For example, it is possible to add SOAP header information that instructs a server to add transaction or authentication information.

• Headers are also important in building piped architectures where processing is done in stages and data is modified as it is passed from handler to handler.

• The SOAP Body: An element that must appear in a SOAP message. The Body element is where the transported XML is loaded. SOAP makes no assumptions about the kind of XML transported in the body of a SOAP message. The data may be domain-specific XML or it may take the form of a remote procedure call.



• Figure 4.11. SOAP messages have a common format that includes a SOAP Envelope, an optional Header, and a Body section that contains the message content. SOAP also defines a message path and set of roles that SOAP nodes can adopt along a path.