Using Web Services

A few years ago Web services were not fast enough to be interesting.

Thanks to the major IT development the last few years, most people and companies have broadband connection and use the web more and more.

Interoperability has Highest Priority

When all major platforms could access the Web using Web browsers, different platforms could interact. For these platforms to work together, Web applications were developed.

Web-applications are simple applications run on the web. These are built around the Web browser standards and can mostly be used by any browser on any platform.

Web Services take Web-applications to the Next Level

Using Web services, your application can publish its function or message to the rest of the world.

Web services use XML to code and to decode data, and SOAP to transport it (using open protocols).

With Web services, your accounting department's Win 2k server's billing system can connect with your IT supplier's UNIX server.

Web Services have Two Types of Uses

Reusable application components.

There are things applications need very often. So why make these over and over again?

Web services can offer applications components like currency conversion, weather reports, or even language translation as services.

Ideally, there will be only one type of each application component, and anyone can use it in their application.

Connect existing software.

Web services help to solve the interoperability problem by giving different applications a way to link their data.

With Web services you can exchange data between different applications and different platforms.

What is web service?

A 'Web service' (also Web Service) is defined by the W3C as "a software system designed to support interoperable machine-to-machine interaction over a network". Web services are frequently just Web APIs that can be accessed over a network, such as the Internet, and executed on a remote system hosting the requested services.

The W3C Web service definition encompasses many different systems, but in common usage the term refers to clients and servers that communicate over the HTTP protocol used on the Web. Such services tend to fall into one of two camps: Big Web Services and RESTful Web Services.

"Big Web Services" use XML messages that follow the SOAP standard and have been popular with traditional enterprise. In such systems, there is often a machine-readable description of the operations offered by the service written in the Web Services Description Language (WSDL). The latter is not a requirement of a SOAP endpoint, but it is a prerequisite for automated client-side code generation in many Java and .NET SOAP frameworks (frameworks such as Spring, Apache Axis2 and Apache CXF being notable exceptions). Some industry organizations, such as the WS-I, mandate both SOAP and WSDL in their definition of a Web service.

More recently, RESTful Web services have been regaining popularity, particularly with Internet companies. These also meet the W3C definition, and are often better integrated with HTTP than SOAP-based services. They do not require XML messages or WSDL service-API definitions.