A Preview of Active Server Pages

Microsoft's Active Server Pages technology is still a relatively new way to create dynamic Web sites and Web-based distributed applications. However, during its short life span, it has evolved to become the foremost tool in the Windows-oriented Web programmer's toolbox. This is probably due to the ease with which complex pages and applications can be created, combined with the ability to use home-grown custom components, and existing Microsoft and 3rd party commercial components, through the Component Object Model (COM/COM+) architecture. Microsoft is currently working on the next generation of ASP, provisionally called ASP+. While it still supports existing ASP pages and applications, ASP+ is actually a complete rewrite of the existing versions. It changes the way that you need to think about ASP and your Web-based applications and Web sites. 'A Preview of ASP+' is the first book to outline the changes and the new ways that you can use ASP in your applications.

What Does This Book Cover?

This book was written as Microsoft was about to release the first preview version of ASP+. This release is almost feature complete, and stable enough for developers to begin learning about and using the new technology. While we can't guarantee that the final release version will be identical, you can be sure that almost all of the concepts, examples and explanations we provide are accurate within the timeframe of the first full version of ASP+.

In this book, we attempt to explain just what ASP+ is all about, how you can use it, and what you can use it for. We start in Chapter 1 with a look at the overall concepts of ASP+, why and how it has changed, and the things you should know to use it effectively. We also look briefly at the NGWS runtime framework, and see how this integrates with the ASP+ code we write.

Chapter 2 then goes on to look at how we can create dynamic pages with ASP+ in much the same way as we've done with ASP. However, the new architecture of ASP+ allows us to do a lot more than before with a lot less code - the programmer's dream. We show you how ASP+ allows objects that represent HTML controls and elements to be executed on the server, with all the supporting HTML and code required being generated automatically.

To extend the functionality of these server-based controls, we can also use templates and server-side data binding to modify the code that is created. In Chapter 3, we show how to add these features to your pages. ASP+ will ship with a new data access technology called ADO+, which is integrated into the data binding process to provide truly disconnected and versatile recordset capabilities.

In Chapter 4, we introduce and describe a range of advanced ASP+ programming techniques. This includes the new input validation features, reusable 'pagelet' components, output caching support, and techniques for handling errors and debugging your pages.

Chapter 5 introduces another brand new technique called ASP+ Web Services. It demonstrates how you can create XML Services that are accessible across the Internet. Together with a range of new server-side components that come with ASP+, these allow powerful business-to-business applications to be built without the need for the cumbersome techniques we've used in the past.

In Chapter 6, we move on to take a more in-depth technical look at the ASP+ Application Framework. To get the most from ASP+, you need to understand a little more about how requests and responses are managed, and how ASP+ application configuration differs from existing techniques. The good news is that it's much easier than ever before, through a far more flexible and extensible management system.

While the server-side controls provided with ASP+ are undoubtedly powerful and useful, you may need to create your own at some stage, or extend the controls that are provided. This might be in order to achieve new functionality, or to provide broader coverage for different kinds of client-side user agent. Chapter 7 looks at how we can build our own server-side controls, and add them to the ASP+ environment.

Finally, in Chapter 8, we look at an application that was designed and built by Microsoft as an example of the way that ASP+ can be used. It takes advantage of many of the new features in ASP+ and the universal runtime, and will help you to get a feel for how complete applications can be created.

Who Is This Book For?

This book covers a product that is still under development, and as such it is aimed at experienced ASP developers who are working at the leading edge - rather than the casual ASP developer or beginner. For example, we do not cover the basics of COM, ASP, or the programming and scripting languages we use in this book.

However, the fact that (at the time of writing) the product is still a preview version does not mean that you can ignore it. ASP+ is going to arrive with the new NGWS runtime package, and it will probably also be part of the next release of Visual Studio (which should contain tools to help you work with ASP+).

So, our aim is to cover conceptual overviews of the product - including some of the background theory and explanation of why the product has developed along the lines it has. This is followed by deeper investigation of the features that developers will use first. We show how to take advantage of the new features quickly and with the minimum of fuss.

Providing that you have used ASP before, and are reasonably comfortable with the concepts, you should be able to use this book without requiring any other reference material (other than the SDK and Help files provided with the product). You should also be comfortable with the general principles of using COM to instantiate and use components, and the Visual Basic (or VBScript) languages. Some of the samples are written in other languages, such as C++, JScript and C# (read as "C Sharp") that are supported by the universal runtime framework, but you don't need to be fluent in these languages to be able to use this book.