This article is designed to provide you with a general overview of XML Web services. It will then show you how to integrate an XML Web service into CorelDRAW® using the Microsoft® VBA Web Services Reference tool.

XML Web services are standards-based building blocks that enable developers to create Web applications that can be shared across the Internet. XML Web services are designed to perform a variety of functions that allow other applications and Web services to share and interact with data across multiple platforms and devices.

XML Web services share three key features:

• Simple Object Access Protocol (SOAP) — SOAP is a communication protocol for Web services that defines the XML format for messages. It specifies the rules for locating, communicating between, and integrating XML Web services into Web applications.
• Web Services Description Language (WSDL) — WSDL describes a set of SOAP messages and how they are exchanged. WSDL can describe XML Web service interfaces that are accessible from a wide variety of platforms and programming languages. It can also define where a Web service is available and what communications protocol is required to interact with it.
• Universal Discovery Description and Integration (UDDI) — UDDI is a Web-based directory that describes Web services offered by businesses and provides necessary contact information. UDDI is designed to integrate businesses offering Web services across the Internet.

Benefits of Web services

More and more companies are realizing that Web services based on an XML infrastructure offer them a number of benefits that are not easily realized using other technologies. With the rise of distributed computing initiatives, such as Microsoft .NET, XML Web services are becoming increasingly important to the future of the Internet.

XML Web services offer a number of compelling benefits.

• industry standards — SOAP, WSDL, UDDI, and XML provide a consistent, uniform way of creating and integrating Web services.
• flexibility — XML is highly extensible, making it easier to transform, repurpose, or adapt data to specific situations.
• cross platform and device compatibility — Services can be accessed and integrated across multiple platforms and devices.
• integration — By linking applications, services, and devices, users are given the ability to access data or Web services any time, any place, and from any smart device.
• new business opportunities — The UDDI directory makes it easy for businesses offering Web services to contact each other.
• new revenue streams — The UDDI directory gives business an opportunity to generate new revenue streams by making their XML Web services available to others.

Examples of XML Web services

A few examples of XML Web services are

• a stock-quote service that uses a stock ticker to list current stock prices
• a traffic-report service that describes traffic congestion based on ZIP codes
• a weather service that lists the current temperature by ZIP code

Each XML Web service is independent but you can create a single page that displays multiple services.

You can see examples of XML Web services at http://www.salcentral.com/salnet/browsecat.asp

Learn more about the Web Service References Tool.