Web services support in CICS TS V3.1 IBM-CICS

In CICS TS 3.1, support was added for Web services, meaning that applications running in a traditional CICS environment could now participate in a Web services environment as either service providers, requesters, or both. Years of investment into application design and implementation are now increasing their value by being able to participate in new technologies without the need for re-programming.

This section discusses the support added to CICS to enable a Web service environment.

1. Web services assistant utility

This utility contains two programs, DFHWS2LS and DFHLS2WS:

  • DFHWS2LS helps you to map an existing WSDL document into a high level programming language data structure.
  • DFHLS2WS helps you to create a new WSDL document from an existing language structure.

The Web services assistant supports the COBOL, PL/I, C, and C++ programming languages.

2. Deploying CICS applications

The Web services support allows you to take two different approaches for deploying CICS applications:

  • Using the Web services assistant. This approach helps you to deploy an application with the least amount of programming effort. For example, if you want to expose an existing application as a Web service, you can start with a high-level language data structure, and use DFHLS2WS to generate the Web services description. Alternatively, if you want to communicate with an existing Web service, you can start with its Web service description and use DFHWS2LS to generate the high-level language structure to use in your program.

Both DFHLS2WS and DFHWS2LS generate a file called the wsbind file.When the application runs, CICS will use the wsbind file to transform the application data into a SOAP message on output, and it transforms the SOAP message to application data on input.

  • Write your own code. To have more control over the processing of your data, you can write your own code to map between your application data and the message that flows between the service provider and service requester. For example, if you want to use non-SOAP messages in the Web service infrastructure, you can write your own code to transform between the message format and the format used by your application.

3. PIPELINE for message handling

A new concept in CICS TS 3.1 is the pipeline. A message handler is a program in which you can perform your own processing of Web service requests and responses. A pipeline is a set of message handlers that are executed in sequence.

A pipeline configuration file needs to be created by the CICS systems programmer to determine which message handlers should be invoked in a particular pipeline. It is an XML file that describes both the message handler programs and the SOAP header processing programs that CICS invokes when it processes the pipeline. The pipeline can be configured as either a service requester pipeline or service provider pipeline.

The PIPELINE resource definition is also required, which is used by CICS to handle the Web service request. It contains the name of the pipeline configuration and the location of the WSDL and wsbind files.

4. Message handlers for SOAP

CICS provides SOAP message handler programs to assist in the configuration of your pipeline as a SOAP node.

  • A service requester pipeline is the initial SOAP sender for the request and the ultimate SOAP receiver for the response.
  • A service provider pipeline is the ultimate SOA receiver for the request and the initial SOAP sender for the response.

The CICS-provided SOAP message handlers can be configured to invoke one or more user-written SOAP header processing programs and to enforce the presence of particular headers in the SOAP message.

5. Web services resource definitions

The following resource definitions are all that is needed to configure support for Web services:

  • PIPELINE
  • URIMAP
  • WEBSERVICE

The application programming interface for these definitions follow the traditional invocations:

  • SOAPFAULT ADD | CREATE | DELETE
  • INQUIRE WEBSERVICE
  • INVOKE WEBSERVICE

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