Web Services: Revolutionising application integration

Web services—self-contained business functions that operate over the Internet—are growing in importance. VidyaSagar has more on the technology and its working

Web services are pieces of functional code that can be shared across the Internet using industry standard protocols. What XML did to the problem of data exchange across multiple platforms, Web services promise to achieve for sharing function across the Internet. It has been portrayed as a new programming model to overcome the difficulties in application integration—across multiple platforms and using multiple languages.

This technology is expected to revolutionise the application integration process leading to enormous business benefits in terms of legacy re-use, flexible and dynamic design and aggregation of best-of-breed services to cope with changes in the business environment, improved business efficiencies and business process integration across vendors and partners. Amazon and Google are among the vendors who are using this technology to share the functionality implemented as a part of their websites. Several financial institutions have adopted the technology, including Merryl and Llyods TSB.

How does it work?

The technology has been modelled after a real-life business way of working. If you want to build a house, you would get an architect to design the house, a builder to build it and an electrical contractor to do the wiring and so on. The choice of these service providers is likely to depend on several factors—some of which could be specialisation in the type of house we want to build, cost and timelines. You would do a bit of shopping around using the telephone directory, get a quotation, check references and then decide which way to go.

In the Web services model, building an application works in a similar way. When you need a particular service (e.g: credit verification), you look up a directory of published Web services, choose the one that fits your requirements, look up the interface (what needs to go in and what comes out for each function you want to use) and then build your application to simply send the required information and get back the results. (In the credit verification scenario, you may send the SSN and other details of a person and get back a credit score).

The service providers publish their software services along with details of the business, the nature, description of services and the service interfaces, into a common registry. The users of these services can discover these via the registry, get the interface descriptions of the services in a standard language (called Web services description language or WSDL) and build applications using these interfaces through remote procedure calls using a standard protocol provided for this purpose (simple object access protocol, or SOAP). The data within the SOAP packets follows XML standard formats and is easily understandable across the service vendor and the service user.

The registry also has some standards agreed to by several of the major IT vendors and is governed by the Universal Description, Discovery and Interface (UDDI).

A single implementation of common functionality residing on a server (such as organisational policies for risk limits or interest rates for different risk profiles) can be shared by all the applications irrespective of the platforms, applications run on or language used for implementation.

Benefits

Several business benefits result from the use of Web services for an enterprise. Some of these are detailed below:

Application integration
The loosely coupled nature of Web services simplifies the process of application integration by enabling disparate systems to work together by borrowing functionality available across the intranet or the Internet. As each of the systems only need to understand the standard SOAP, WSDL interfaces without worrying about the implementation aspects (such as platform, language, data representation etc.) of the functionality, making systems work together is made easier.

Legacy re-use
A considerable amount of business functionality is encapsulated in legacy systems today. Using this functionality in new systems involves significant effort, as the new systems need to re-implement this functionality or build complex interfaces using proprietary methods. Businesses building Web interfaces discover this painful reality everyday. Using the Web services model, one only needs to wrap existing functionality into services and publish them so any other application desiring to use this functionality can be developed. Most of the legacy vendors provide tools for this purpose. In addition, several application mining tools (such as SEEC) provide facilities to generate these wrappers.

Vendor integration
With the increasing need for efficiencies and responsiveness, businesses are looking at integrating their systems with their vendors’ systems closely. This tight integration enables an organisation to use information present in its suppliers’ systems and leverage that knowledge to increase competitiveness and add to its bottom-line. Web services ease the process of this integration as they provide these disparate systems to interact using standard interfaces in a platform independent manner.

Best-of-breed services
The ability to use functionality over the Internet makes it possible to build applications using best-of-breed implementations available from third party suppliers. Just as an automobile manufacturer can assemble a car with the best parts made by others or use parts which he cannot make, an application can be assembled by using best-of-breed or complex software functionality implemented by others. This enables new applications to be put together with functionality that is difficult or impossible to develop in-house. One good example of this is the gene matching algorithm Web service provided by the EMBL (European Molecular Biology Laboratory) which provides matching gene sequences given a new gene sequence. The expertise required for this functionality is not common but using this Web service and integrating this functionality into another application is as simple as using any method call in a visual basic program.

The author is vice president, Technical R&D at Kanbay. He can be contacted at vsagar@kanbay.com