SOAP

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SOAP started life as a way of invoking DCOM (Distributed COM) methods in a more loosely coupled way than regular COM method invocations. It evolved into a specification that allowed for methods to be invoked on dissimilar systems across Internet protocols (HTTP, FTP, and so on). SOAP and BizTalk are similar in their approach to interchanging information but each is optimized for different transaction types.

SOAP is at the core of a Microsoft initiative called Web Services. Web Services offers a new way of looking at the Web. By using an HTML browser to look at information, information consumers force content providers (pretty much anyone on the Web) to "dumb down" their data so that human eyes can consume it. By removing the formatting requirements for the data, the data can be delivered in a raw format, allowing services to aggregate and process that data, ultimately offering it to users with added value. An example of such data is real-time weather. A travel site could combine its content with weather reports to provide next week's travelers with a tentative weather forecast. A Web site that provides weather as HTML pages can generate extra income by providing the raw weather data as an XML stream in response to a real-time request for weather in a particular location to parties who will pay to repackage that content.

Like the platform-independent BizTalk, you can send a SOAP method invocation to a Perl script running on Solaris, which in turn invokes a Java class to extract data from an Oracle database. The response is sent as an XML document object, which then can be used in your application. You don't need to know what platform your service is running on.

To understand BizTalk and SOAP, you need to understand the underlying syntax that makes it all possible—XML. In fact, BizTalk is an extension of SOAP, using SOAP to deliver a business document over HTTP. When you are using BizTalk, you are using SOAP and XML as well.

Part I of this book is an introduction to XML from a business and technical point of view. The purpose of this introduction is to provide a perspective for building and interchanging business information using XML structures.

This first part is really the XML book I wanted to write. Even if you don't care about BizTalk or SOAP, I hope you will find some value in the description of XML in Part I, which is aimed at the developer.

Part II of the book discusses the BizTalk Framework and shows how you can use XML and BizTalk today to create e-commerce applications. In Part III we actually build some BFC servers using various Microsoft and non-Microsoft tools.

I enjoyed writing this book because it gave me a chance to discover some great stuff happening in the B2B (business-to-business) marketplace. I think SOAP and Web Services will truly change the way people think about their jobs and even their lives. BizTalk will provide companies with a standard, cost-effective way to replace paper when doing transactions.

Now I need to concentrate on my next work, 1,001 Duck-Bar Jokes. If we should meet, let me know your favorite Duck-bar joke and I'll buy you a beer.