Join David Gassner for an in-depth discussion in this video Understanding how ASP.NET works, part of ASP.NET Essential Training.
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ASP.NET is one of the family of software packages known as application servers. An application server is a piece of software that's installed on a web server to create a dynamic application platform. The world wide web includes many clients and servers that are connected over the Internet. Technically speaking, they communicate using a protocol called TCP/IP. This is the protocol that connects all of the computers in the whole world together. When these computers talk to each other, they exchange messages in a format known as HTTP, which stands for HyperText Transfer Protocol. This sort of communication is used whether you are working with a static website, that is a website that delivers static fixed web pages, or a dynamic web application such as those that are supported by ASP.NET.
Here is how a static web page works. The web client makes a request for the resource, let's say a web page, by sending an HTTP formatted request over the Internet to the server. The server responds by locating the file on its hard disk that has been requested. This is known as a static web page with a file extension of typically of .htm or .html. The web server responds by sending that content back to the client and the client, which might be a web browser on a personal computer, renders and displays the web page visually.
When you move to the dynamic environment, the application server software is installed on the same computer as the web server. Let's say Internet Information Services and ASP.NET. The application server, in this case ASP.NET, can communicate with the database and with other server resources. Once again, the web client makes the HTTP formatted request. The web server talks to the application server. The application server talks to the database and other network resources and then it's up to the web server to construct an HTML formatted response, which once again is sent back to the web client.
The important thing here is that the web browser doesn't know that there is an application server at work and therefore doesn't need any additional software. It requests an HTML page and it receives an HTML page and it doesn't know the difference between one that's static and fixed on the server's hard disk and one that's being generated dynamically in response to which request. There are many software packages that you can select from as application servers. If you are watching this video series, you have probably already selected ASP.NET or you are evaluating it for possible use in your organization. Microsoft Active Server Pages or ASP is another option that you might select. Active Server Pages is an older version of Microsoft's Application Server Technology.
You can also select Adobe ColdFusion, a cross operating system product that works on many operating systems including Windows, Mac and Linux and that uses its own proprietary language, ColdFusion Markup Language. Some developers use PHP, a completely free and open source product that once again is available on many operating systems. And for Java developers, there are many application server products available including Websphere from IBM, Weblogic from Oracle, formerly from BEA, JBoss, a completely free J2EE or Java-based server and others, and finally there is Microsoft's ASP.NET.
So that's a look at the basic architecture of ASP.NET. In another videos in this chapter, I describe how to install ASP.NET along with the product called Visual Web Developer, an integrated development environment that can get you started quickly building ASP.NET-based, dynamic web applications.
- Storing data with SQL Server
- Using the GridView control to present and edit dynamic data
- Creating a data entry system
- Attaching external CSS files
- Creating pages to log in and authenticate visitors
- Installing Internet Information Services (IIS) on Windows XP and Windows Vista
- Deploying an ASP.NET website on IIS