PHP Cookbook

Chapter 8. Web Basics

Introduction

Web programming is probably why you’re reading this book. It’s why the first version of PHP was written and what continues to make it so popular today. With PHP, it’s easy to write dynamic web programs that do almost anything. Other chapters cover various PHP capabilities, like graphics, regular expressions, database access, and file I/O. These capabilities are all part of web programming, but this chapter focuses on some web-specific concepts and organizational topics that will make your web programming stronger.

Recipe 8.2, Recipe 8.3, and Recipe 8.4 show how to set, read, and delete cookies. A cookie is a small text string that the server instructs the browser to send along with requests the browser makes. Normally, HTTP requests aren’t “stateful”; each request can’t be connected to a previous one. A cookie, however, can link different requests by the same user. This makes it easier to build features such as shopping carts or to keep track of a user’s search history.

Recipe 8.5 shows how to redirect users to a different web page than the one they requested. Recipe 8.6 explains the session module, which lets you easily associate persistent data with a user as he moves through your site. Recipe 8.7 demonstrates how to store session information in a database, which increases the scalability and flexibility of your web site. Discovering the features of a user’s browser is shown in Recipe 8.8. Recipe 8.9 shows the details of constructing a URL ...