Web Services, Part I: Introduction

In this column we embark on a new series on Web services. Web services are expected to revolutionize our life in much the same way as the Internet has during the past decade or so. Web services provide a common protocol that Web applications can use to connect to each other over the Internet. The main advantage of Web services is that they are based on industry standards. The services are described in XML and are communicated over the existing HTTP infrastructure. The union of XML and HTTP forms one of the new industry buzz words: Simple Object Access Protocol (SOAP). Publicizing Web services is done via two standards: Universal Description, Discovery, and Integration (UDDI), and DISCO (abbreviation of Discovery). The big computer companies are betting on this new technology. They are developing platforms, tools, and kits to help build Web services.

You can write and call Web services in almost any language: VC++, C#, VB, Java, and JavaScript. In upcoming columns, we will show you how to use our favorite language, JavaScript. In this column, we will describe Web services in general. We will show you what problems Web services are trying to solve, what the benefits are of using Web services, what's behind SOAP and UDDI, and what development tools Microsoft, IBM, and Sun are promoting. We will show you where to find Web services on the Internet, and how to check their quality, before you try calling them. We'll end this column by explaining the structure and various elements of the Web service description file, written in the standard Web Service Description Language. We'll demonstrate WSDL with the Temperature-Weather Web service. This Web service accepts a message with your zip code, and returns the weather in your area.

In this column you will learn:

• About Web services justification
• How to benefit from Web services
• How to use SOAP and UDDI
• How to use development tools for Web services
• How to find Web services on the Internet
• How to find information about a Web service
• How to check interoperability between Web services
• How to write WSDL by example
• How to write the Web service's description elements

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