WebSphere Message Brokers
File: ac00476_
Writer: Kate Hostler

Concept topic

This build: July 31, 2007 21:16:45

Web services message format

Messages that pass across this transport have an XML format that provides platform-independence. The XML content that defines specific operations, and error situations (SOAP Fault), is defined by the SOAP standard. Because delivery is not guaranteed, applications must provide recovery in the event of system or network failures.

A message contains components that are appropriate to its type:

Command string
A request message contains the command POST followed by a URL. The command string ends with HTTP/1.0.
Status line
A response message contains a status line that starts with HTTP/1.0 , and indicates the success or failure of the request with a code and text, for example 200 OK, 404 Not Found, 500 Server Error.
Headers
The headers used by the Web services protocol are HTTP headers that consist of a name followed by the characters colon and (optionally) a space, followed by the value (contents) of the header. Each header is followed by the characters <CR><LF>. The final header is followed by <CR><LF><CR><LF>, which creates a blank line. Data following this line is interpreted as message body data. Headers are described in Web services headers.
Body
The message body is the data following the headers in the message (that is, following the characters <CR><LF><CR><LF>). For an inbound message received by the HTTPInput or HTTPRequest node, this data is typically parsed according to the settings of the message properties in the node. For outbound messages, the data is typically parsed according to the settings of the message properties in the Properties folder received by the HTTPReply or HTTPRequest node that parses the message from message tree to bit stream.

In most cases, the body of a message is XML. However, an inbound message can contain a different format if the receiving node is configured to handle that format and the appropriate parsers are available. An outbound message can contain a body of any format that is accepted by the Web service to which it is sent.

An error that is generated by a component other than a Web service (for example, 404 Not Found) might result in a message that is in HTML format.

The bit stream containing headers and body are parsed and represented within the message tree when an input request is received by an HTTPInput node, or when a response from a Web service is received by the HTTPRequest node. A bit stream is created by parsers from the appropriate parts of the message tree when a reply is sent to the client by the HTTPReply node, and when a request is sent to a Web service by the HTTPRequest node. For further details about these actions, see the individual node descriptions.

Related concepts
Message flows overview
Generate WSDL
Related tasks
Developing message flows
Generating a WSDL definition from a message set
Deploying
Related reference
WebSphere MQ Web Services Transport
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Copyright IBM Corporation 1999, 2007Copyright IBM Corporation 1999, 2007. All Rights Reserved.
This build: July 31, 2007 21:16:45

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