Audience

If you are looking for a step-by-step introduction to programming FlashCom, have a look at the introductory chapters of this book. If you feel they are over your head, consult the resources cited in the previous paragraph before returning to this book. Also consider books such as Flash Remoting: The Definitive Guide and the ActionScript Cookbook (also from O'Reilly) for targeted coverage of other areas of interest.

The book is not a printed version of the online documentation, nor does it attempt to reproduce materials on widely available topics, such as how to install FlashCom. Instead, it is designed to clarify and extend the information provided by Macromedia's documentation and web site. See in particular the documentation available at:

http://www.macromedia.com/support/documentation/en/flashcom/index.htm

This book was written by people who have used FlashCom and Macromedia's documentation from the earliest days of the product. We all had to struggle to understand just what Macromedia had given us and hope to help you avoid having to repeat all our early tests and experiments. The book is designed to be read and reread as your experience developing Flash communication applications increases.

The changes in Flash from versions 4 to 5 were revolutionary, and the changes from version 5 to MXamong them components and video supportwere also very dramatic. Flash MX 2004 introduced ActionScript 2.0 and added an entire new set of user interface components. ActionScript 2.0 added some features familiar to C++ and Java programmers, such as strong typing and formal classes.

In Chapter 1 through Chapter 12, the book's client-side ActionScript examples are written in both ActionScript 1.0 and ActionScript 2.0. From Chapter 13 onward, the client-side samples are written almost exclusively in ActionScript 2.0 and use the newer v2 Flash UI components. All server-side FlashCom code is written in Server-Side ActionScript, which uses ActionScript 1.0 syntax, because that is the only supported version.

Among the reasons for the mixture of ActionScript 1.0 (AS 1.0) and ActionScript 2.0 (AS 2.0) throughout the book:

• The communication classes provided for client-side scripting, such as SharedObject, NetStream, and NetConnection, were all designed to use AS 1.0-style dynamic methods and properties. In Chapter 13, I show how to wrap shared objects up so that you can use AS 2.0, but that is an extra step and not something provided by Macromedia. Macromedia's communication components are available only in AS 1.0 and require the Flash UI client-side v1 components. For example, the Chat component's client-side code is written in AS 1.0 because the communication components were originally built for Flash MX and have not been updated to AS 2.0.

• Server-Side ActionScript (SSAS) is JavaScript 1.5, which is very close to AS 1.0. The client-side classes such as SharedObject and NetConnection also exist on the server where AS 1.0 must be used to do the same sort of work you must do on the client such as setting up onStatus( ) or onSync( ) event handlers. That is, it is much easier to port client-side AS 1.0 code than AS 2.0 code to SSAS.

• ActionScript 2.0 is a superset of ActionScript 1.0. I think this is something people coming from the Java world or just discovering the discipline of strong typing, formal class and interface definitions, and so on often forget. AS 2.0 code compiles down to the same bytecode as AS 1.0, allowing AS 2.0 code to be exported for use in Flash Player 6 (although Flash Player 6 doesn't support all the latest AS 2.0 classes). Regardless, ActionScript provides all the benefits of a simple scripting language, such as loose typing and dynamic objects, while offering the option of stronger typing and formal classes. AS 2.0 simply provides new options that are particularly valuable for larger-scale projects.

• ActionScript 2.0 means different things to different developers. On the syntactic level, it means support for strict typing and different commands (such as import instead of #include). On the architectural level, it includes support for formal classes, packages, and interfaces. In the end, the purpose of the book is to teach FlashCom programming, not ActionScript 1.0 or 2.0. We didn't want to obscure the basics of FlashCom programming with a heavy reliance on object-oriented programming (OOP) and formal classes. This allows scripters of all levels to focus on the new FlashCom material.

• Robust, deployment-ready code is not conducive to learning a topic. The book often presents pared-down examples, but the web site has full-blown code examples in both AS 1.0 and AS 2.0 format, when appropriate.