Table Of ContentMastering PHP 4.1
by Jeremy Allen and Charles Hornberger ISBN: 0782129242
With this latest version of PHP you can quickly construct web
apps, connect them to databases with ease, and more.
Back Cover
Table of Contents
Mastering PHP 4.1
Introduction
Part I The Basics of PHP
Chapter 1 - Beginning Your Exploration of PHP
Chapter 2 - Variables
Chapter 3 - Operators and Expressions
Chapter 4 - Flow Control and Functions
Chapter 5 - Strings and Arrays
Part II Programming Principles and PHP
Chapter 6 - Object-Oriented Programming
Chapter 7 - Debugging and Errors
Part III Letting the Data Flow
Chapter 8 - SQL and Database Interaction
Chapter 9 - Forms and User Interaction
Chapter 10 - Data Validation
Chapter 11 - Sessions
Chapter 12 - Security
Chapter 13 - Files and Networking
Part IV How PHP Is Connected
Chapter 14 - Web Application Development
Chapter 15 - XML and XHTML
Chapter 16 - LDAP
Part V Using PHP in the Real World
Chapter 17 - PDF
Chapter 18 - Generating Graphics
Chapter 19 - E-Mail
Part VI Appendixes
Appendix A - A Crash Course on Installing PHP
Appendix B - PHP Configuration Options
Appendix C - XHTML Entities
Index
List of Figures
List of Tables
List of Listings
List of Sidebars
Mastering PHP 4.1
Jeremy Allen
Charles Hornberger
Associate Publisher: Richard Mills
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To Erin: your patience and caring make anything possible.
—Jeremy Allen
To Charles Semmelman.
—Charles Hornberger
Acknowledgments
Everything started with my parents, so they get the first thanks for bringing me into this world! Thank you
Erin, for giving up so much of our time together, and for being so patient and understanding.
Thanks to the entire team involved with this project! Although not directly involved with Mastering PHP
4.1, thanks to Tom Cirtin for giving me the opportunity with my first professional writing project. Next
comes Diane Lowery, who had to work with an author who had his own ideas about how schedules
worked—thank you, Diane. Charlie Hornberger deserves much credit here for the tremendous amount of
work he did with this book. Thanks to Pete Gaughan for his tireless editing efforts and insight. Thanks to
Liz Burke for keeping everything, and everyone, straight! Thanks to our technical editor, Mark Godfrey,
for keeping it all technically coherent. The team at Sybex has been awesome, and fundamental to this
book.
Thanks to the development team at elliptIQ for being so supportive of me writing this book.
—Jeremy Allen
I'd like to thank many people for their help putting this book together, especially: my coauthor, Jeremy
Allen; Liz Burke, for keeping everything running smoothly even when I wasn't; editor Pete Gaughan, for
painstaking and thoughtful application of the knife; and Diane Lowery, for bringing me on board in the
first place.
—Charles Hornberger
The Basics of PHP
Part I:
Chapter List
Chapter 1: Beginning Your Exploration of PHP
Chapter 2: Variables
Chapter 3: Operators and Expressions
Chapter 4: Flow Control and Functions
Chapter 5: Strings and Arrays
Beginning Your Exploration of PHP
Chapter 1:
Overview
Developing applications and sites for the World Wide Web, or for Web-like uses such as intranets, has
become one of the most extensive areas of computing and programming work. If it can be done digitally,
then somebody, somewhere, is trying to adapt it to a web browser. Understanding the various flavors of
web activity—static and dynamic pages, client-side and server-side systems—is a necessary step
toward increasing your flexibility as a developer.
PHP builds upon the familiar structure of programming languages such as C, Java, and Perl. It helps
create dynamic HTML content by providing the necessary tools to easily manipulate that content. PHP is
becoming one of the preeminent tools for increasing the power of web pages because it is easy to use
yet powerful. Building a few elementary scripts, testing the two main methods of moving data back and
forth, and learning to comment PHP code will demonstrate just how accessible PHP's features are.
Developing for the Web
The term web development paints a wide, long stroke. It is a general term to categorize a large variety of
activities. Web development can mean anything from putting a static HTML page on a small World Wide
Web site to developing a massive, continent-spanning, corporate intranet that handles mission-critical
business communications. But these activities do break down into several manageable categories.
Web Applications
To get into the topic of developing web applications, first we must tackle the term application: What is an
application? What should an application do?
An application is any software developed to simplify or perform a task. The level of the task varies from
very specific to more general. A program that takes the grades of a student's six classes, averages those
grades, and summarizes them in a report is a simple, but limited, application. On the other hand, an
application that provides the means to communicate with others, such as an online groupware app (one
that allows users to coordinate their workflow), is more complex and achieves a more general goal.
Although the scope of the groupware application is much wider than the scope of the grade-averaging
program, both are still applications.
Then, what specifically are web applications? A web application, in general, is an application that
leverages the ubiquity and ease of communication the Internet provides. A more restricted definition of
web application—the one that will be used throughout the book—is an application that uses a web
browser as the client. There are many client-side technologies available to most web browsers. In
general, the most far-reaching and easily accessed web applications are those that use simple and
elegant Hypertext Markup Language (HTML). A few examples that strictly fit the term web application are
web-based banking systems, auctions, and news sites.
Static and Dynamic Websites
Static sites have content that does not change until the author updates it, and these sites work well for
many people because they allow information to be shared. However, static sites provide no interaction
with visitors and do not accomplish any tasks in a programmable way.
Dynamic sites allow user interaction. Although, like a static site, a dynamic one uses HTML for the client
interface, it also allows users to take individual and customizable actions, such as reserving and
purchasing a particular airline flight or even seat. The purpose behind an online ticketing system is
straightforward: an easily usable interface that provides convenience to the user. With such a system
globally available to a web terminal, the task of buying a ticket is decentralized and easy to accomplish.
HTML is a text-based markup language. Ideally, HTML is used to define the content and sketch its
structure, and cascading style sheets (CSS) are used to position and style the content. Of course, due to
backward compatibility and the wide range of clients used, CSS may be a less-than-optimal choice for
positioning content. And beyond that, because of the static nature of HTML (meaning it is just a simple,
text-based language), it is itself limited when we want to make our content change and evolve.
HTML provides an excellent means of sharing content with a variety of web-based clients, but it has
several drawbacks. When an HTML document is requested from a web server, the web server returns
the document to the requester—nothing more. This is just a way to publish content, not create, control,
organize, or customize it. HTML as it is used today tends to focus on the content's visual quality, not its
detailed structure.
Server-Side vs. Client-Side
HTML is a client-side technology, meaning that an HTML document is processed entirely by the client. A
web server doesn't behave differently based on the code contained within an HTML document. A web
server merely provides requested files; the client browser makes the decisions about rendering them.
HTML is not a programming language; it does not provide any constructs for data processing of any kind.
PHP, conversely, is entirely server-side. When a PHP script executes, it doesn't interact directly with the
browser; only the final product of the PHP script, which usually is an HTML document, is dealt with by the
requesting browser. If a browser were sent an unprocessed PHP script, the browser would attempt to
render the PHP script as regular HTML. Browsers cannot execute PHP scripts.
HTML is an integral component to web application development. PHP code can be embedded and mixed
directly into HTML. When a client requests an HTML document from a web server, the server responds
by directly sending the document to the client. Figure 1.1 shows a client requesting a HTML document
and illustrates how the server responds.
Figure 1.1: HTML document request
Requesting a PHP script works differently. Before the document is sent to the client, the document is
processed by PHP, and the PHP engine executes any PHP code found in the document. Figure 1.2
illustrates a client request for a PHP script. The PHP script in this illustration returns a processed HTML
document.
Figure 1.2: PHP script request
Description:Chapter 6 - Object-Oriented Programming. Chapter 7 Chapter 17 - PDF. Chapter 18 . Although not directly involved with Mastering PHP.
