Web Services - Building Blocks of Web Application Development
As kids, we all remember having played with building blocks and quite often constructed things easily with them. Now imagine having such building blocks for our IT requirements as well...?
They exist: Web services!
So, what exactly are Web Services? Is it a new technology, is it a new way of providing business services or is it something that existed before but now has turned out to be, the same old wine in a new bottle?
Well, simply defined a web service is a service which can be accessed over the web. The key is SERVICE. The Oxford Concise English Dictionary gives the definition of service as "the act of helping or doing work for another or for a community etc." As such web services would mean providing a service using the web as the medium or services assembled together over the web to provide more complex functionalities.
Web Services in itself is not an entirely new concept – being built on technologies that have always existed. Previously, if one had to access business functionalities remotely, then they could use CORBA, EJB or DCOM depending on the platform on which the service was hosted. But there were some problems with this approach. Problems like proprietary technologies (hence platform lock-in), incompatibility between various platforms, inability to invoke components over HTTP etc prevented wide adoption of small granular services. But now, thanks to web services, people can offer specialized services, build on other services or stitch together different services. There is a whole plethora of new possibilities.
Why Web Services?
Web services are discrete web-based applications that can interact dynamically with other web services or stand alone consumers. The dynamic behaviors that Web services exhibit include:
• Self-descriptive functionality
• Publishing of service descriptions
• Location of required functionality
• Request for required data
• Data exchange with other Web services
And of course since all Web services are, developed to the same standards for self-description, publishing, location, invocation, communication and data exchange capabilities, they can work seamlessly together.
The technologies chosen for Web services are inherently neutral to compatibility issues that exist between programming languages and operating platforms since all the interaction with web services happen using XML over HTTP. Accordingly, applications using web services can dynamically locate and transparently use necessary functionality, whether available locally or from across the Internet, regardless of the programming languages or operating platforms involved. This means a web service written using Java can be invoked from a windows client written to the .NET platform or from a web application developed using PHP. Its true language independence.
What web services can do for you?
Web services allows you to link with employees, customers, partners and suppliers. Web services helps you maximize your ROI by allowing you to fully utilize your existing systems, develop new systems in no time that would have been otherwise required and all the while providing for full security.
Extracting value by leveraging existing assets:
Web services gives you a way to get the most out of your existing systems – without having to re-program, reengineer or replace anything. Your valuable information assets remain intact and undisrupted. Now you can make more use out of your IT assets in ways that were too costly or time-prohibitive before.
Adding a web service interface to your existing systems can enable them to be accessed anytime, anywhere from any device. This means your existing services work even harder for you than ever before.
One purpose for which Web services are extremely useful is integrating legacy systems into new e-business applications. Web services allow you to leverage valuable legacy assets without disrupting or exposing mission-critical legacy systems. A web service interface can be developed for the existing legacy systems that allow your latest eBusiness initiative to talk to your legacy application and fully leverage the capabilities already present in your legacy application.
Develop new applications rapidly
You can rapidly develop Web services using the application development tools you’re already familiar with. The major Web application infrastructures, including Java™ 2 Enterprise Edition (J2EE™), Microsoft .NET, and IBM® Web Sphere® offer extensive support for Web services standards. Often, all you need to do is define the desired interfaces and functions, and the software automatically generates the necessary code. By abstracting and delegating complex business rules and workflows to existing or new applications, you can create your new e-business applications quickly and with less development effort.
A Web service once developed and published can be used by any application on any device or platform. A single Web service can be consumed for numerous purposes across and beyond your organization, as well as combined with other Web services. As long as your development environment supports Web services technologies, you can use the exhaustive and ever growing library of web services to cut down on your own development effort. If a service already exists, it often makes good business sense to use the service provided rather than write your own application to provide the functionality.
The inherent security of Web services
Web services give the owners of various enterprise systems control over what functions and data they want to make available to other applications or parties. With full support for authentication and authorization, providers can choose to provide only those functions they wish to expose for consumption, thereby retaining the ability to manage the security and availability of their systems. With Web services, you can exercise granular control over precisely what logic and data you want to expose and whom you want to expose that.
