SOAP - Messages

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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 −

https://www.w3.org/2001/12/soap-envelope

The default namespace for SOAP encoding and data types is −

https://www.w3.org/2001/12/soap-encoding

Note − All these specifications are subject to change. Thus, keep updating yourself with the latest specifications available on the W3 website.

SOAP - Message Structure

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>