CODE Framework: Building Services and SOA Business Layers

In today’s application landscape, there only seems to be one aspect that is certain: Uncertainty. Which UI technology or which mobile platform will be dominant in the years to come? We know that for business applications especially, rich Windows UIs are still very popular and the most productive type of application. We also have no doubt about the significance of Web applications in general, and HTML5 in particular. We know that iOS and Android are important mobile operating systems, and we hope Windows Phone will catch up. There also is a good chance that Windows 8 Metro will have a significant role to play. But do we know any of these for sure? And how many of these does any system have to support now or in the future? Even if you know that you want to build your application based on HTML5, which is going to be the predominant tool for building such applications a few years down the road? Or which approach to building Windows 8 Metro applications will be the one you choose?

In short: It is currently impossible to answer many of these questions now, and it’s certainly impossible to answer these questions if you are aiming for a 5- or 10- or even 20-year horizon. 20 years may seem like an extremely long time in IT, but realistically speaking, databases that have been maintained for 10 or 20 years, or business logic that has its roots in VB6 is not uncommon. In fact, one of the most common operating systems in use today (Windows XP) is now more than a decade old. Although UI choices and platforms (such as phones and slates) have changed very rapidly and will likely continue to do so, middle-tiers and databases have evolved at a much slower pace. Consider CODE Magazine as an example. The subscriber system we are using for the magazine has continually evolved over the years, but many of its components are now over a dozen years old and that is perfectly fine.

So how do you work productively as a developer or architect in such an environment? How can you build middle tiers, business logic, and databases in a way that will live up to the standards you set in the last decade or two, not to mention expectations in the future? How can we fulfill the expectations of a technical and economic environment where it is not acceptable to have to throw out the entire application to support the latest mobile device or browser? And how do we fulfill those expectations in a way that’s a realistically feasible approach, highly productive, creates highly flexible and exquisitely architected systems that are easy to maintain without a large squad of rocket-science-level developers, and generally promotes high quality as a goal that is easy to achieve?

Services are the Answer

I believe very strongly that Services and SOA (Service Oriented Architecture) are a very good answer to this problem. And by that, I do not mean the creation of XML Web Services or the creation of REST Services or any similar technology you might choose. Instead, I am talking about creating services that are more abstract and broken out as generically callable objects with an agreed-upon interface (“contracts”). Once such abstract services are created, various deployment choices can be made.

Do you feel that REST is the ideal way to get to those services? Fine choice! You like XML Web Services, and SOAP better? That’s fine with me too. You prefer binary optimized services for efficiency? In scenarios where binary optimized services are technically possible, they might be the best choice of all. But these are decisions that are made later. Start out with a REST Service and you might be stuck with REST forever. The same is true for many systems that are based solely on SOAP. But if you start out generic, you have great freedom in choice. Perhaps you use TCP/IP-based services initially, but then decide you want to write an iOS or Android client, and REST is the better choice for that. With solid architecture, that is simply a deployment choice.

None of these aspects are new. SOA has been around for a while and different types of service standards as well. But how do you really approach a project that utilizes SOA and do so in a way that is highly productive yet at the same easy to do, even for junior developers? And how do you really call services using all these different standards?

If you have done service work in the past, you know that a lot of this theory is not necessarily the way things work in the real world. Lots of services are stuck in SOAP. Lots of services are REST-based and cannot adjust to other standards. In fact, many environments are specifically geared towards the creation of specific types of services but can’t easily cross over to other standards. If you are using WCF in .NET, you are in a pretty good position, as WCF is highly flexible; even so, services created for SOAP do not easily translate to REST and vice-versa.

By: Markus Egger

Markus is an international speaker, having presented sessions at numerous conferences in North & South America and Europe. Markus has written many articles for publications including CoDe Magazine, Visual Studio Magazine, MSDN Brazil, asp.net Pro, FoxPro Advisor, Fuchs, FoxTalk and Microsoft Office and Database Journal. Markus is the publisher of CODE Magazine.

Markus is also the President and Chief Software Architect of EPS Software Corp., a custom software development and consulting firm located Houston, Texas. He specializes in consulting for object-oriented development, Internet development, B2B, and Web Services. EPS does most of development using Microsoft Visual Studio (.NET). EPS has worked on software projects for Fortune 500 companies including Philip Morris, Qualcomm, Shell, and Microsoft. Markus has also worked as a contractor on the Microsoft Visual Studio team, where he was mostly responsible for object modeling and other object- and component-related technologies.

Markus is a Microsoft RD and has continually received the Microsoft MVP Award since 1996 for his contributions to the developer community. Visual LandPro, one of the applications Markus was responsible for, was nominated three times in the Microsoft Excellence Awards.

megger@eps-software.com