One of the challenges about a topic like SOA (Service Oriented Architecture) or Web Service is not that there is a lack of information. On the contrary, the problem is that there is too much information out there, such as in publications, on the Internet, or from vendor data sheets. A Google search of “SOA” yields over 50 million hits, while a “Web Service” search returns over 419 million results. So, where are you going to start, and how long is this going to take you to learn all these?
Don’t let this daunt you. In this article, we will distill the key essentials of SOA and Web Services into several simple, understandable concepts, especially focusing on what are relevant to your NonStop world.
- SOA is an architecture, not a product
Service Oriented Architecture, as the term implies, is a conceptual framework, not a product. You can compare it with other terms like: Client/Server, Object Oriented Programming or Distributed Processing. The way to implement SOA is usually via Web Services.
- Web Service is more than just a Web application
If you have an application running on a web service that interacts with a browser user, that is not a web service. Web Service refers to a standard method of communication using certain protocols, which we will cover later.
- Web Service is Remote Procedure Call (RPC)
Technically, Web Service can provide more than RPC function. But practically, most applications use Web Service to allow a Client program on one platform calling a Server program or routine on another platform. This also implies that Web Service involves an application to application, end-to-end protocol environment.
- Web Service makes it easy for inter-platform communication
This is the essence of Web Service: by following this standard, applications on one platform can easily invoke the service on another platform.
Web Service and NonStop
Guess what? Web Service is basically a different implementation of something you already know very well in the NonStop world: Pathway. Let’s look at some of the the similarity between Web Service and Pathway.
In Pathway, you have a Requester (Client) communicating with a Server (Server Class) over a message-based protocol.
Web Service is based on the same principle, except that it enables the Client or the Server to exist on platforms other than NonStop over an intranet or the Internet. For example:
- You can have a client program on another platform like .NET, accessing your Pathway COBOL Server using Web Service.
- You can have a requester program on the NonStop, such as SCOBOL or COBOL, accessing a Stock Quote Service over the Internet (for example, this Quote Service from www.xignite.com). In this case, note that we don’t even have to care what platform that service runs on over the Internet.
Here are some of the technical differences between them:
|Pathway||Web Service (WS)|
|Server||Server Class||WS Server
(or just WS)
|Platform||NonStop only||Any platform|
|Communication protocol||Guardian message system||HTTP|
|Message Structure||NonStop ASCII||XML|
|Requester/Response Protocol||Guardian message system||SOAP|
|Request/Response structure||IPM layout||WSDL|
If you are interested in learning more about the components used in Web Service, you can request a copy our PowerPoint presentation which explains what XML, SOAP and WSDL are.
Why is Web Service important to NonStop?
Web Service can open up many new possibilities to NonStop applications, such as:
- Allowing other platforms to access NonStop applications easily
- Enabling NonStop applications to leverage other services and applications within your company
- Interfacing to 3rd party packages such as PeopleSoft, SAP or Siebel within the enterprise
What is next?
Now that we have reviewed the basics of Web Services, in our next blog SOAP/AM Overview, we will show you how you can turn a Pathway Server into a Web Service in 5 minutes!
Phil Ly is the president and founder of TIC Software, a New York-based company specializing in software and services that integrate NonStop with the latest technologies, including Web Services, .NET and Java. Prior to founding TIC in 1983, Phil worked for Tandem Computer in technical support and software development.