A SOAP message is an ordinary XML document containing the following elements −
Envelope − Defines the start and the end of the message. It is a mandatory element.
Header − Contains any optional attributes of the message used in processing the message, either at an intermediary point or at the ultimate end-point. It is an optional element.
Body − Contains the XML data comprising the message being sent. It is a mandatory element.
Fault − An optional Fault element that provides information about errors that occur while processing the message.
All these elements are declared in the default namespace for the SOAP envelope − http://www.w3.org/2001/12/soap-envelope and the default namespace for SOAP encoding and data types is − http://www.w3.org/2001/12/soap-encoding
NOTE − All these specifications are subject to change. So keep updating yourself with the latest specifications available on the W3 website.
The following block depicts the general structure of a SOAP message −
<?xml version = "1.0"?> <SOAP-ENV:Envelope xmlns:SOAP-ENV = "http://www.w3.org/2001/12/soap-envelope" SOAP-ENV:encodingStyle = "http://www.w3.org/2001/12/soap-encoding"> <SOAP-ENV:Header> ... ... </SOAP-ENV:Header> <SOAP-ENV:Body> ... ... <SOAP-ENV:Fault> ... ... </SOAP-ENV:Fault> ... </SOAP-ENV:Body> </SOAP_ENV:Envelope>