SOA Web Services - Designing Sound Web Services

Designing Sound Web Services for Integration

The Web Services technology plays an important role when applying the concepts of Service-Oriented Architectures. The web services technology is based on open standards such as:

• XML—eXtensible Markup Language
• SOAP—Simple Object Access Protocol
• WSDL—Web Services Description Language
• UDDI—Universal Description, Discovery, and Integration

The use of open standards enables the interoperability between different vendor solutions. The existing solutions can be wrapped as web services and new services can be developed without the need to know who the consumer is. The consumer can consume any web service irrespective of the platform on which it is running using the standard web protocols. This enables the just-in-time integration of the applications and allows the business to establish new partners on the fly. Thus, the web services technology is the right candidate for creating SOA.

Web Services Architecture

The web services architecture is shown in the following figure.

A service provider creates the service and publishes it on a UDDI registry for consumers to discover it. A consumer queries the registry and obtains a reference to the service interface from the registry. After the interface is obtained, the consumer creates a programming interface to the service. The consumer then consumes the service using standard SOAP protocols. The request is directed through a web server protected by firewalls to the service provider.

This is one way of invoking the service. Another way of invoking the service would be to use a messaging server in place of a web server.