CICS Atom support as RESTful service
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Create and use Web services and RESTful services in CICS, Part 2: CICS Atom support as RESTful service
This is a second installment in a series of posts that introduces Web services and RESTful services development in IBM's Customer Information Control System (CICS). In Part 1, we went through an introduction to Web Services and REST services, so we will continue here with looking at more details of how CICS implements RESTful access through Atom.
First, it is worth noting that Atom is both a protocol and an XML format for providing content "feeds" on the Web. In other words, an "Atom feed" is a web feed provided using the Atom protocol and format. This provision of updated content is known as "syndicating" a web feed. Web users can subscribe to a syndicated feed that allows them to see new content as soon as it is available.
CICS first introduced Atom protocol support in Transaction Server version 4.1
In a CICS system, the provided implementation for Atom resources can access and "feed" content to and from Files, TS queues and application programs.
The following graphic shows, on a conceptual level, relationship between various components of the CICS runtime environment that participate in the Atom-based resource access.
Don't worry if some of the things on this diagram look puzzling or unfamiliar. The important part is, CICS can act as an HTTP endpoint that receives a REST request through its TCPIPSERVICE component. Based on the information in the URI, CICS matches the request to an ATOMSERVICE component, which in turn accesses the target resources (TS Queue, File, or Program).
In future posts we will go through additional details of each of the CICS system components. We will also look at tools and methods of developing and setting up a CICS system and developing some test clients that can access CICS Atom feeds provided by a COBOL program.
About the author
Gary Mazo is a Senior Software Engineer with IBM Rational Developer for System z (RDz). Gary joined IBM in 1987, and spent 10 years developing compilers and compiler tools. Lately, Gary has been actively involved in creating service-oriented architecture (SOA) tools for RDz. He holds 6 software patents and enjoys tinkering with all things related to software and hardware.