Web Services

The idea of several heterogeneous computers exchanging data with one another is nothing new. Since however most software and hardware systems are based on different principles (from both a technical and structural standpoint), you can expect most attempts at exchanging data between several systems to fail. These are the very reasons behind developing a standard that can successfully convey data in all directions between the most different of computers. Welcome to the world of web services!

Web services are being increasingly used in the business-to-business sector. They have established themselves as an efficient tool in integrating a wide range of applications. One typical application scenario for using web services is a customer-supplier relationship. Let us assume that we want to make communication between both partners more efficient and more cost-aware. Linking the relevant partner information systems is the obvious answer. But this would bring with it a serious disadvantage. Opening up the information systems would mean the disclosure of internal data and therefore a relinquishment of power to the partner gaining access to the information system. We can now see that the transparent exchange of relevant data needs to not only be independent of the systems used but also requires filtering. This would mean that only relevant information could be included in the data exchanged: nothing more and nothing less.

With a limited web service, this can be done via an interface to a particular program function which can be reached via a network and is based on Internet standards. It therefore becomes the binding block assuming the role of a go-between. The interface can be accessed and used by a client program such as Remote Procedure Call. In principle, there is nothing new about this because established technologies such as DCOM or Corba can already be used with the corresponding services. But these technologies are always linked to particular platforms or programming languages which means that the client and server have to be very closely linked. Unlimited web services, on the other hand, can overcome the barriers currently experienced by the limited services. Technologies are no longer specified. The only specification is the SOAP transfer protocol which runs via HTTP. This results in some interesting benefits:

total independence from operating systems and hardware used.
free choice both of programming language and the structures used.
easy use via the Intranet since the http port is approved on the firewalls.
use of https for secure communication.
and much more…

The key technology behind today’s web service developments is XML, but a well-formed and valid XML document is far from being considered a web service. Additional technology is needed to exchange XML coded data between client and server which in turn must be done in a standardized form.

You could write pages and pages about web services and analyze them from both economic and technical standpoints. However, to come to the point, let us mention the following. To use web services to gain real added value for the company, the existing heterogeneous information systems have to communicate with one another via expertly implemented web services.