Asp .net

ASP+ Frames .NET

It would be difficult to call the original implementation of Microsoft Active Server Pages (ASPs) a framework. Other than its session support, which required HTTP cookies, ASPs were merely HTML files with the ability to run some script code as the page was generated. Forget everything you know about ASPs from the past. ASP+, the latest piece of Microsoft's .NET architecture, is a huge step forward in Web application development. ASP+ brings the benefits of familiar event-driven programming using real programming languages to the entire Web, including older and stripped-down browsers.

I have to admit, I was stunned as I dug into the beta 1 release of ASP+. In stark contrast to the Microsoft of yore, known for stapling together a few existing Microsoft products and calling it a Web solution, ASP+ was reworked from the ground up. The result is a framework that can, with a single-source base, target both uplevel and downlevel browsers. No longer are we restricted to pseudolanguages like JScript and VBScript for development: beta 1 supports Visual Basic and C#, with others on tap. The spaghetti code that was so difficult to avoid in ASPs has been transformed to something manageable, like lasagna. In short, Microsoft has done what I've always berated them for not doing: It used its unbelievable pool of talent to rethink a popular development product and do it right.

State of the Web

An important question in any Web application framework is a client's state is managed in the stateless world of the browser. The original ASP implementation had an Achilles' heal: HTTP cookies were required to manage session state information. ASP+ does not require cookies and can purportedly manage state correctly across a server farm, implying that at least a chunk of the state information is stored on the client's page. Less reliance on the server for state information translates to a more scaleable server.

Web Forms

Web Forms are the most powerful features of the ASP+ framework. Traditional Web applications are built by chaining together Web pages or calling the same page over and over with varying parameters, but Web Forms allows programmers to work like we used to work before the arrival of the Web -- using event-driven programming. Reading the code of an ASP+ Web Form is similar to reading the code for a Visual Basic application. If you didn't know better, you'd read the code and understand how the page will behave when particular events occur. But wait, you do know better: Web pages may be generated on the server, but they execute on the client. How can we have portable, event-driven code if the target browser might not even support JavaScript? The secret is that Web Forms generate appropriate HTML 3.2 - or better -- code to represent the form. If the target browser supports advanced features, certain events may be handled on the client. If not, the page makes a roundtrip and handles the event on the server instead. For example, if you specify that a submit button should execute its OnClick behavior on the server, when the user presses the Submit button, the state of the page is restored on the server and your OnClick handler is called.

Web Controls

To effectively leverage Web Forms, you need some controls. ASP+ provides Web Controls that map to standard HTML objects, as well as advanced visual controls, data validation controls, and data binding controls. You can also create your own custom Web Controls. All ASP+ controls have a namespace component that ensures against namespace collisions between control libraries. The provided Web Controls make it simple to create a catalog extracted from a database, using a template element to specify the precise HTML layout you require.

The simplicity of the resulting code screams "maintainability," something missing from previous ASP versions. The code and layout can be separated, making it easier to farm out the design portion of your site to an artist rather than a programmer.

Web Methods

Many business-to-business solutions depend on providing a site's content to a customer or partner in a nonvisual manner. The ASP+ concept of Web Services is designed to tackle this problem. By developing in a .NET-compliant language and identifying' the Web-accessible methods of your object with a [Web-Method] tag, you can deliver your nonvisual content to the world. For example, a shipping company might expose a method that takes a shipping weight and address as inputs and returns a shipping cost as a result. These Web Methods can then be called either via an HTTP POST, HTTP-GET, or the new XML standard HTTP-SOAP. When developing Web Methods, Web Controls, and Web Forms, you can take advantage of a real debugger, complete without cross-language source debugging. No longer is Response. Write() the only means of finding problems in code.

ASP+ shows that Microsoft finally gets the Web. By providing a framework that simultaneously supports advanced development techniques and downlevel browsers, ASP+ becomes the first Web development platform that I am genuinely excited to use.

Eric Binary Anderson has led projects at a number if enterprise software companies and is currently the senior architect at IBT Financial (Bend, Ore), an Inte.net-based training company.