Beginning PHP4

822 Pages·2000·8.98 MB·English

by  Chris Lea

Beginning PHP4

Wankyu Choi
Allan Kent
Chris Lea
Ganesh Prasad
Chris Ullman
with
Jon Blank
Sean Cazzell

Wrox Press Ltd. 
Beginning PHP4

© 2000 Wrox Press

All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any
form or by any means, without the prior written permission of the publisher, except in the case of brief
quotations embodied in critical articles or reviews.

The author and publisher have made every effort in the preparation of this book to ensure the accuracy of the
information. However, the information contained in this book is sold without warranty, either express or
implied. Neither the authors, Wrox Press nor its dealers or distributors will be held liable for any damages
caused or alleged to be caused either directly or indirectly by this book.

Published by Wrox Press Ltd,
Arden House, 1102 Warwick Road, Acocks Green,
Birmingham, B27 6BH, UK
Printed in the United States
ISBN 1861003730
Trademark Acknowledgements

Wrox has endeavored to provide trademark information about all the companies and products mentioned in
this book by the appropriate use of capitals. However, Wrox cannot guarantee the accuracy of this information.
Credits

Authors Technical Reviewers
Wankyu Choi Luis Argerich
Allan Kent Darren Beale
Chris Lea Mark Fehrenbacher
Ganesh Prasad Dario Ferreira Gomes
Chris Ullman Chris Harshman
Andrew Hill
Contributing Authors Mark Mamone
Jon Blank Jurgen Prins
Sean Cazzell Mark Roedel
Bart Ssyszka
Additional Material Rick Stones
Simon Cozens Travis Swicegood
John Kauffman Kevin Yank
Dan Squier
Production Manager
Technical Architect Laurent Lafon
James Hart
Production Project Co-Ordinator
Technical Editors Pip Wonson
David Mercer
Christian Peak Figures/Illustrations
Dan Squier Shabnam Hussain
Julia Gilbert
Mark Waterhouse Cover
Shelley Frazier
Category Manager
Viv Emery Chapter Divider
Dan Squier
Author Agent
Lynne Bassett Proofreaders
Fiona Berryman
Index Odette Randall
Alessandro Ansa

Project Administrator
Nicola Phillips
About the Authors
Wankyu Choi
Wankyu holds a Master's degree in English/Korean interpretation and translation from the Graduate School of
Translation & Interpretation. He is the president/CEO of NeoQuest Communications, Inc. running a PHP-
powered English language education portal (http://www.neoqst.com) in the Republic of Korea. He is
independently working on an open source PHP project called NeoBoard (http://www.neoboard.net), a
feature-rich web discussion board.

I'd like to thank my parents for their encouragement and guidance, the dedicated staff at Wrox
and technical reviewers for all their hard work, the staff at NeoQuest for their support while
working on the book, and last but not the least, my wife, Yonsuk Song for her patience and love
for this particular computer nerd.
Allan Kent
Allan has been programming seriously for the last 7 years and other than the single blemish when he achieved
a Diploma in Cobol programming, is entirely self-taught. He started his career working at the local University
and now runs his own company. Allan lives in Cape Town, South Africa with his girlfriend and 5 cats.
Chris Lea
Chris is one of the co-founders of Lucid Designs (http://www.luciddesigns.com), a Venice, CA based web
design and development firm. He received a BS in Physics with Highest Honors and Distinction from UNC-
CH in 1997, and has been hacking away with lots of (mostly open source) software since then. During his
tenure with Lucid, he has worked on a wide variety of web site development projects ranging from the
entertainment industry to the financial sector. When he's not staring at his monitor, you can usually find him
swing dancing somewhere in the Los Angeles area. For more information, you can always check out his
personal site at http://www.chrislea.com/.
Ganesh Prasad
Ganesh has worked in IT for 13 years, specializing in applications software design and development, in a
number of countries including India, the United Arab Emirates, and Australia. He currently works for Reply2
Ltd., Australia, an e-CRM service provider. His experience covers IBM mainframes, VAX and UNIX minis, as
well as Windows client/server and Web-based programming. Interests include Java and Open Source software,
and his hope is that Open Source software will bring cheap computing to the masses and kick-start Third
World economies. He is an Australian citizen, and lives in Sydney with his wife Sashi and son Lalit.

I'd like to thank my wife Sashi for her patience, support and encouragement. She took all my
other responsibilities off my shoulders, allowing me to concentrate on the task of writing.
Chris Ullman
Chris Ullman is a Computer Science graduate who came to Wrox five years ago, when 14.4 modems were the
hottest Internet technology and Netscape Navigator 2.0 was a groundbreaking innovation. Since then he's
applied his knowledge of HTML, server-side web technologies, Java, and Visual Basic to developing, editing,
and authoring books. When not trying to reconstruct the guts of his own PC or trying to write extra chapters in
a hurry, he can be found either playing keyboards in psychedelic band, The Bee men, tutoring his cats in the
way of eating peacefully from their own food bowl and not the one next to theirs, or hoping against hope that
this is the year his favorite soccer team, Birmingham City, can manage to end their exile from the Premier
League.

Thanks to James and Sarah B for getting me involved on this project and Christian, David, and
Dan for deciphering, organizing, and improving my work, and most importantly thanks to my
wife Kate, for being there.
Jon Blank
Jon Blank has been a part of the Linux world since before "Linux" was a buzzword, and has been
programming (much to the detriment of his social life) in various languages for the better part of his life. He
came to the PHP world by way of Perl, and came to Perl by way of The Web Union, an experimental Web
hosting provider for students and non-profit organizations that he runs in his spare time. He currently lives in
the New York City area, where he is trying to craft a stable career in a field where tempting offers are always
around the corner. He doesn't think he'll succeed.

Jon's interests include online role-playing, vintage computers and video games, and graphics arts, as well as
many sorts of programming. His primary focus as a programmer is on automation – convincing the computer
to do the sort of boring and/or repetitive work that only a computer can stand.

Table of Contents
Introduction 1
Why PHP4? 2
The Prompt 2
What Do I Need To Use This Book? 3
PHP4 Resources 4
Conventions 4
Downloading the Source Code 5
Support & Errata 5
Online Forums at p2p.wrox.com 6
Checking the Errata Online at www.wrox.com 6
Wrox Developer's Membership 6
Finding Errata on the Web Site 8
Adding Errata and Obtaining e-Mail Support 9
Customer Support 9
Editorial 9
The Authors 9
What We Can't Answer 9
How to Tell Us Exactly What You Think 9
Chapter 1: Installation 11
Installing PHP4 on Windows 95 and 98 13
Obtaining PWS 13
Setting Up PWS 15
Installing PHP4 Alongside PWS 17
Installing PHP4 on Windows NT and 2000 19
Installing PHP4 Alongside IIS 24
Installing PHP4 on Linux and Other UNIXes 28
Choosing Your Installation Method 29
Obtaining RPMs 29
Which Packages Do We Need? 30
Configuring and Starting Apache with PHP4 31
Testing Your Installation 34
ii
Chapter 2: Writing PHP Programs 39
An Example PHP Program 40
Viewing a Web Page 44
Client-Server 44
Internet Protocols 44
The HTTP Protocol 45
The HTTP Request 46
The HTTP Response 48
Where PHP Comes Into This 49
Server-Side Scripting 50
Identifying a PHP Script 51
Caching 51
Variables 52
Data Types 55
String Data Type 55
Numeric Data Types 58
Constants 63
The Define Keyword 64
Initialization 64
Conversions 65
Type Casting 67
gettype and settype 67
isset, unset, and empty 68
Environment Variables 68
Summary 69
Chapter 3: Getting Data from the Client 71
Web Forms 72
The FORM Tag 72
Attributes of FORM 72
ACTION 72
METHOD 73
HTML Form Controls and PHP 76
Text Fields (Text Boxes) 76
Text Areas 80
Check Boxes 82
Radio Buttons 88
List Boxes 91
Hidden Controls 95
Passwords 99
Submit Buttons and Reset Buttons 99
Using Values Returned From Forms In Your PHP Scripts 100
Summary 106
Chapter 4: Decision Making 109
Conditional or Branching Statements 110
An Example of Branching in Day to Day Life 110
If Statements 111
Boolean Values 112
iii