Apache: The Definitive Guide, Second Edition

4.1. Turning the Brochure into a Form

Creating the form is a simple matter of editing our original brochure to turn it into a form. We have to resist the temptation to fool around, making our script more and more beautiful. We just want to add four fields to capture the number of copies of each card the customer wants and, at the bottom, a field for the credit card number. Before we get embroiled in artistry, let's look briefly at a bit of theory.

4.1.1. What Is HTTP?

To recapitulate amidst a sea of initials: HTTP (HyperText Transmission Protocol) is the standard way of sending documents over the Web. HTTP uses the TCP protocol. The client (which is normally a browser such as Netscape) establishes a TCP connection to the server (which in our case is Apache) and then sends a request in HTTP format down that channel. The server examines the request and responds in whatever way its webmaster has told it to. The webmaster does this by configuring the Apache server and the files or scripts he or she provides on the system.

The machine's response may be in HTML, graphics, audio, VRML, Java, or whatever new fad the web fanatics have dreamed up since we went to press. Whatever it is, it consists of bytes of data that are made into packets by the server's TCP/IP stack and transmitted. You can find a list of MIME types in the file mime.types or at http://www.isi.edu/in-notes/iana/assignments/media-types/media-types. The meanings are pretty obvious: text/html is HTML, text/plain is plain ...