Developing ASP Components by Shelley Powers

Reviewed by: Songmuh Jong, send e-mail Published by: O'Reilly & Associates, Inc., go to the web site Requires: One of the Visual Studio products (Visual C++, Visual Basic, or Visual J++), version 5 or 6; experience with Active Server Pages (ASP), and preferably access to IIS on Windows NT Server 4.0 or above with the Option Pack (including ASP service) installed MSRP: US$39.95 (Ed Note: reviewed in 1999) Since my last review of the IDG book "Active Server Pages for Dummies", I had the opportunity to work on an Internet project using ASP heavily. Because of that, I was excited about reviewing this book which describes how to create ASP components that can be used together with the ASP pages. For those of you who are new to this, ASP pages are server scripts that reside on the server and called by HTML pages. ASP scripts can also be embedded in the HTML pages, but will be interpreted and compiled into standard HTML code before it is sent back to the user's browser. ASP components, on the other hand, are usually DLL files that reside on the server and are called by the ASP script to perform pre-compiled codes. This book is mainly for programmers who are interested in developing ASP components, which are kinds of COM objects promoted by Microsoft.

There are three types of Microsoft products that are able to create ASP components, including Visual C++, Visual Basic and Visual J++. This book discusses all the three products. In essence, this book is divided into four sections, the last three being devoted to one of the products. Therefore, the book is not so thick as it appears when one needs to read only the section for one compiler. For this review, however, I have tried all the compilers that are accessible to me. My Visual J++ 1.1 does not create components automatically. However, it came with the utility javareg.exe that would register the resulting Java classes. My Visual C++ 5 and Visual Basic 5 are all capable of creating COM projects even though the screens are different from that shown in the book. The author obviously used Dev Studio 6, which provides more automation and options to the creation of ASP components.

The first part of this book is an introduction to the ASP, components, threads, transaction, Microsoft Transaction Server, and the ASP objects. Anyone who has tried to set up the ASP environment can tell you that it is not straightforward unless you are using the most recent Option Pack for NT Server. This book has also a chapter in part I to describe how you can establish the ASP environment. It also points out the most compelling reason to write ASP components instead of ASP scripts: to create a profitable solution for your projects. There is little you cannot achieve with ASP scripts that you can do in ASP components. However, you cannot expect a high profit if the buyers can read your scripts and customize them by themselves. Other reasons are well described in the book.

Writing ASP scripts or components is easy once you master the art of interaction with the ASP objects and database access objects. The ASP objects are essential for you to create dynamic HTML pages while the database is obviously the ultimate object you want to interact with. The ASP (or in fact any E-commerce projects) exists because we need a solution to process user data. Because of that, client/server programmers have a definitive advantage in understanding the whole process. This book describes in detail all the aspects of accessing various objects with lots of sample codes. It covers also the N-tier ASP components--a subject most appreciated by Client/Server programmers.

In summary, this book is an ideal introduction and reference for programmers who are experienced in ASP scripts but want to learn ASP components. The free-style discussion covers all of the programming scenes you'll ever encounter in creating a web site using ASP no matter you are using Visual C++, Visual Basic or Visual J++. The only thing it lacks is an extensive discussion of the difference between Internet Explorer and Netscape Navigator, although some examples are displayed with Navigator.

As a web developer, I suffer from the incompatibility between browsers everyday. Codes working for Internet Explorer may not work with Navigator and sometimes vice versa. Most of the time, I develop for Navigator first because it makes stricter demands of syntax. Hopefully, the browser war can end with standards applicable to all browsers. Before that, make sure that your ASP code generates a browser-compliant HTML page. Otherwise, they may not be displayed at all!

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