Web Application Examples

Let's quickly look at the most basic example of a web application (so simple it is hardly a web application at all). Consider a straight HTML request in which a user 1) instructs a web browser to 2) contact a web server using the HTTP protocol, and 3) ask it for a specific 4) HTML document which the server 5) returns to be 6) displayed by the web browser.

We might also have a slightly more complex example. Suppose a user supplied search parameters via an 1) HTML form that the web browser 2) sent to a web server using an SSL connection. The web server might 3) process that data with a CGI script by connecting to a 4) data file, searching it based upon the user query, and 5) sending back the results to be 6) displayed in the web browser window as a table.

This pattern could be made much more complex of course. For example, suppose we have a 1) Java client which 2) sends an encrypted request to a Java Web Server 3) which processes the request with a Java Servlet that uses a CORBA object to systemically generate 4) financial trade data in the form of XML with an associated XSL style sheet that is 5) sent back to the Java client to be 6) parsed into an XML Tree and displayed according to the XSL.

As you see, in the web application workflow, a motley of technologies can be used to perform various tasks.

In fact, there are literally hundreds of technologies and tools used throughout this simple process. The sheer number of pieces is why many developers feel overwhelmed when they look at the processes of web application development. However, regardless of how many technologies are involved in a project, for the most part they can all be placed into one of four conceptual categories.

That is, a technology will fall into the category of 1) the display layer(GUI), 2) the communication layer, 3) the middleware layer, or 4) the data layer.

You'll see that when you confront a new web development technology, that if you can place it in one of these categories, that you will immediately understand what it is, what it does, and probably most of how it does it. Every technology has its own syntax and quirks of course, but armed with this broad understanding and a desk reference book, any new technology should incorporate into your toolbox within a week or two regardless of how cryptic the acronym is.

But perhaps a picture would be best here. Consider the sections in the typical web application and what tools fall into the categories. In the next sections we will focus on each of these categories and the technologies they harbor.

Looks quite complex eh? Well that is the reason web application developers can get overwhelmed. However, as we've been saying, there is no need to feel overwhelmed when you can take this giant lego statue apart and examine it block by block.

In the next installment we'll start with the Display/GUI Layer.

The Thick of Things
Introduction to the Web Application Development Environment (Tools)
The Display (GUI) Layer