When you want to perform specialized processing on the messages
that flow between a service requester and a service provider, and CICS® does not
supply a message handler that meets your needs, you will need to supply your
own.
In most situations, you can perform all the processing
you need with the CICS-supplied message handlers. For example, you can use
the SOAP 1.1 and 1.2 message handlers which CICS supplies
to process SOAP messages. But there are occasions when you will want to perform
your own, specialized, operations on Web service requests and responses. To
do this, you must supply your own message handlers.
- Write your message handler program. A message handler
is a CICS program
with a channel interface. You can write your program in any of the languages
which CICS supports,
and use any CICS command
in the DPL subset within your program.
Compile and link-edit your program. Message
handler programs normally run under transaction CPIH, which is defined with
the attribute TASKDATALOC(ANY). Therefore, when you link-edit
the program, you must specify the AMODE(31) option.
- Install the program in your CICS system in the usual way.
- Define the program in the pipeline configuration file. Use
the <handler> element to define your message handler.
Within the <handler> element, code a <program> element
containing the name of the program.