David Powers

Lightening Your Workload with Includes

The ability to include the contents of one file inside another is one of the most powerful features of PHP. It’s also one of the easiest to implement.

Pages That Remember: Simple Login and Multipage Forms

The Web is a brilliant illusion. When you visit a well-designed website, you get a great feeling of continuity, as though flipping through the pages of a book or a magazine. Everything fits together as a coherent entity. The reality is quite different. Each part of an individual page is stored and handled separately by the web server. Apart from needing to know where to send the relevant files, the server has no interest in who you are. Each time a PHP script runs, the variables exist only in the server’s memory and are normally discarded as soon as the script finishes. Even variables in the

Getting Ready to Work with PHP

_POST and

Getting Started with a Database

_GET arrays have only a brief life span. Their value is passed once to the next script and then removed from memory unless you do something with it, such as store the information in a hidden form field. Even then, it persists only if the form is submitted.

Creating a Dynamic Online Gallery

Now that you’ve decided to use PHP to enrich your web pages, you need to make sure that you have everything you need to get on with the rest of this book. Although you can test everything on your remote server, it’s usually more convenient to test PHP pages on your local computer. Everything you need to install is free. In this chapter, I’ll explain the various options and give instructions for both Windows and Mac OS X.

Generating Thumbnail Images

Dynamic websites take on a whole new meaning in combination with a database. Drawing content from a database allows you to present material in ways that would be impractical—if not impossible—with a static website. Examples that spring to mind are online stores, such as Amazon.com ; news sites, such as the BBC ( www.bbcnews.com ); and the big search engines, including Google and Yahoo! Database technology allows these websites to present thousands, sometimes millions, of unique pages. Even if your ambitions are nowhere near as grandiose, a database can increase your website’s richness of content with relatively little effort.

Using PHP to Manage Files

The previous chapter concentrated mainly on extracting the contents of the images table as text. This chapter builds on those techniques to develop the mini photo gallery shown in Figure 12-1.

What Is PHP—And Why Should I Care?

PHP has an extensive range of functions designed to work with images. You’ve already met one of them, getimagesize(), in Chapter 4. As well as providing useful information about an image’s dimensions, PHP can manipulate images by resizing or rotating them. It can also add text dynamically without affecting the original; it can even create images on the fly.

How to Write PHP Scripts

PHP has a huge range of functions designed to work with the server’s file system, but finding the right one for the job isn’t always easy. This chapter cuts through the tangle to show you some practical uses of these functions, such as reading and writing text files to store small amounts of information without a database. Loops play an important role in inspecting the contents of the file system, so you’ll also explore some of the Standard PHP Library (SPL) iterators that are designed to make loops more efficient.

Bringing Forms to Life

One of the first things most people want to know about PHP is what the initials stand for. Then they wish they had never asked. Officially, PHP stands for PHP: Hypertext Preprocessor. It’s an ugly name that gives the impression that it’s strictly for nerds or propellerheads. Nothing could be further from the truth.