OReilly programming PHP 2nd edition apr 2006 ISBN 0596006810

By Rasmus Lerdorf, Peter MacIntyre, Kevin Tatroe .... With style tips and practical programming advice, this book will help you become not just a PHP --Chapters that show you how to gene

By Rasmus Lerdorf, Peter MacIntyre, Kevin Tatroe

Publisher: O'Reilly Pub Date: April 2006 Print ISBN-10: 0-596-00681-0 Print ISBN-13: 978-0-59-600681-5 Pages: 540

Table of Contents | Index

Programming PHP, Second Edition is the authoritative guide to PHP 5 and is filled with the

unique knowledge of the creator of PHP (Rasmus Lerdorf) and other PHP experts When it comes to creating web sites, the PHP scripting language is truly a red-hot property In fact, PHP is currently used on more than 19 million web sites, surpassing Microsoft's ASP NET technology in popularity Programmers love its flexibility and speed; designers love its accessibility and convenience.

As the industry standard book on PHP, all of the essentials are covered in a clear and concise manner Language syntax and programming techniques are coupled with

numerous examples that illustrate both correct usage and common idioms With style tips and practical programming advice, this book will help you become not just a PHP

Chapters that show you how to generate dynamic images, create PDF files, and parse XML files with PHP

Advanced topics, such as creating secure scripts, error handling, performance tuning, and writing your own C language extensions to PHP

of PHP's strengths."

David Dooling, Slashdot.org

By Rasmus Lerdorf, Peter MacIntyre, Kevin Tatroe

Publisher: O'Reilly Pub Date: April 2006 Print ISBN-10: 0-596-00681-0 Print ISBN-13: 978-0-59-600681-5 Pages: 540

by Rasmus Lerdorf, Kevin Tatroe, and Peter MacIntyre

Copyright © 2006, 2002 O'Reilly Media, Inc All rights reserved.Printed in the United States of America

Published by O'Reilly Media, Inc., 1005 Gravenstein HighwayNorth, Sebastopol, CA 95472

O'Reilly books may be purchased for educational, business, orsales promotional use Online editions are also available for

most titles (safari.oreilly.com) For more information, contactour corporate/institutional sales department: (800) 998-9938 orcorporate@oreilly.com

ISBN: 0-596-00681-0

[M]

Today, PHP is the most widely used programming language onthe Web, with over 40 percent of all web applications written inPHP It is installed on over 22 million domain servers (source:Netcraft), as shown in Figure F-1 The number of developersusing PHP has now reached over 2.5 million The communitydeveloping PHP is very impressive, with over 450 CVS

committers who wrote a total of 1 million lines of code The PHPcommunity is one of the most dynamic, with thousands of

people sharing code, evangelizing about PHP, supporting eachother, and creating many projects such as Wikipedia, Mambo,PHP-Nuke, FUDforum, SugarCRM, and Horde, just to mention afew

Figure F-1 PHP development timeline with usage

Its simplicity is what made PHP so successful Simplicity equalsless code Developers and companies have been developing

There is an unacknowledged war that goes on every day

in the world of programming It is a war between the

humans and the computer scientists It is a war betweenthose who want simple, sloppy, flexible, human ways to

write code and those who want clean, crisp, clear, correctways to write code It is the war between PHP and

C++/Java

Adam Bosworth

Google

The future of PHP looks very bright Leading platform vendorssuch as IBM, Oracle, MySQL, Intel, and, most recently, Red Hathave all endorsed it The new Collaboration Project initiated byZend Technologies rallies many leading companies and

community members around new open source initiatives aimed

at taking PHP to the next level by creating an industrial-grade,

de facto standard PHP web application development and

deployment environment The Project's first two open initiativesare:

Zend PHP Framework

This is a web application framework that will accelerate andimprove the development and deployment of mission-

critical PHP web applications

Support for the Eclipse Development platform

Zend is joining the Eclipse Foundation as a Strategic

Developer It will develop, in collaboration with partners, a

Rasmus Lerdorf, the initial creator of the first version of PHP(then called PHP/FI), and Kevin Tatroe provided the guidelinesfor this book The newest author on the revision project is PeterMacIntyre, a Zend Certified Engineer with more than five yearsexperience in PHP Wez Furlong and Chris Shiflett have alsocontributed to this book Wez modernized the "Extending PHP"chapter, and Chris brought his renowned expertise in updatingthe "Security" chapter

This book is a must-have for anybody working with PHP Some

of the most recognizable names in the PHP community havecontributed to it So you know that you are getting quality

Now more than ever, the Web is a major vehicle for corporateand personal communications Web sites carry satellite images

of Earth in its entirety, search for life in outer space, and housepersonal photo albums, business shopping carts, and productlists Many of those web sites are driven by PHP, an open sourcescripting language primarily designed for generating HTML

content

Since its inception in 1994, PHP has swept the Web and

continues its phenomenal growth with recent endorsements byIBM and ORACLE corporations (to name a few) Also, the

millions of web sites powered by PHP are testament to its

popularity and ease of use It lies in the sweet spot betweenPerl/CGI, Active Server Pages (ASP), and HTML Everyday

people can learn PHP and can build powerful dynamic web siteswith it Marc Andreessen, chairman of Opsware Inc and

founder of Netscape Communications, recently described PHP ashaving replaced Java as the ideal programming language for theWeb

and array-handling facilities, as well as greatly improved

The core PHP language (Version 5+) features powerful string-support for object-oriented programming With the use of

standard and optional extension modules, a PHP application caninteract with a database such as MySQL or Oracle, draw graphs,create PDF files, and parse XML files You can write your ownPHP extension modules in Cfor example, to provide a PHP

interface to the functions in an existing code library You caneven run PHP on Windows, which lets you control other

Windows applications such as Word and Excel with COM or

interact with databases using ODBC

This book is a guide to the PHP language When you finish it,you will know how the PHP language works, how to use the

many powerful extensions that come standard with PHP, andhow to design and build your own PHP web applications.

PHP is a melting pot of cultures Web designers appreciate itsaccessibility and convenience, while programmers appreciate itsflexibility, power, diversity, and speed Both cultures need a

clear and accurate reference to the language If you are a

programmer, then this book is for you We show the big picture

of the PHP language, and then discuss the details without

wasting your time The many examples clarify the explanations,and the practical programming advice and many style tips willhelp you become not just a PHP programmer, but a good PHPprogrammer

If you're a web designer, you will appreciate the clear and

useful guides to specific technologies, such as XML, sessions,PDF generation, and graphics And you'll be able to quickly getthe information you need from the language chapters, whichexplain basic programming concepts in simple terms

This book has been fully revised to cover the latest features ofPHP Version 5 We have endeavored to even talk about some ofthe features that were still on the drawing board while we werewriting this edition One feature in particular is the new PDOdatabase interface that was still in development during our

writing, but we felt it important enough to cover in the

discussion on databases (Chapter 8)

This book assumes you have a working knowledge of HTML Ifyou don't know HTML, you should gain some experience withsimple web pages before you try to tackle PHP For more

information on HTML, we recommend HTML & XHTML: The

Definitive Guide by Chuck Musciano and Bill Kennedy (O'Reilly).

We've arranged the material in this book so that you can eitherread it from start to finish or jump around to hit just the topicsthat interest you The book is divided into 15 chapters and 2appendixes, as follows:

Chapter 1, Introduction to PHP

Talks about the history of PHP and gives a lightning-fastoverview of what is possible with PHP programs

Discusses user-defined functions, including scope, variable-functions

Chapter 4, Strings

Covers the functions you'll use when building, dissecting,searching, and modifying strings in your PHP code

engine and the new PDO database interface are covered

Chapter 9, Graphics

Demonstrates how to create and modify image files in avariety of formats from within PHP

Explains how to create dynamic PDF files from a PHPapplication

Chapter 11, XML

Introduces PHP's updated extensions for generating andparsing XML data

Chapter 12, Security

Provides valuable advice and guidance for programmerscreating secure scripts You'll learn best practices

programming techniques here that will help you avoidmistakes that can lead to disaster

Chapter 13, Application Techniques

Talks about the advanced techniques that most PHPprogrammers eventually want to use, including errorhandling and performance tuning

Chapter 14, Extending PHP

An advanced chapter that presents easy-to-follow

instructions for building a PHP extension in C

Chapter 15, PHP on Windows

It also discusses the features unique to Windows, such asCOM and ODBC

The following typographical conventions are used in this book:

Plain text

Indicates menu titles, menu options, menu buttons, andkeyboard accelerators (such as Alt and Ctrl)

Italic

Indicates new terms, URLs, email addresses, filenames, fileextensions, pathnames, directories, and Unix utilities

Constant width

Indicates commands, options, switches, variables,

attributes, keys, functions, types, classes, namespaces,methods, modules, properties, parameters, values, objects,events, event handlers, XML tags, HTML tags, macros, thecontents of files, or the output from commands

Constant width bold

Shows commands or other text that should be typed

literally by the user

Constant width italic

This icon signifies a tip, suggestion, or general note.

This icon indicates a warning or caution.

This book is here to help you get your job done In general, youmay use the code in this book in your programs and

documentation You do not need to contact us for permissionunless you're reproducing a significant portion of the code Forexample, writing a program that uses several chunks of codefrom this book does not require permission Selling or

distributing a CD-ROM of examples from O'Reilly books doesrequire permission Answering a question by citing this bookand quoting example code does not require permission

Incorporating a significant amount of example code from thisbook into your product's documentation does require

permission

We appreciate, but do not require, attribution An attributionusually includes the title, author, publisher, and ISBN For

example: "Programming PHP, Second Edition, by Rasmus

Lerdorf, Kevin Tatroe, and Peter MacIntyre Copyright 2006

O'Reilly Media, Inc., 0-596-00681-0."

If you feel your use of code examples falls outside fair use orthe permission provided, feel free to contact us at

permissions@oreilly.com

Please address comments and questions concerning this book tothe publisher:

http://www.oreilly.com/catalog/progphp2

To comment or ask technical questions about this book, sendemail to:

bookquestions@oreilly.com

For more information about our books, conferences, ResourceCenters, and the O'Reilly Network, see our web site at:

http://www.oreilly.com

When you see a Safari® Enabled icon on the cover ofyour favorite technology book, that means the book is availableonline through the O'Reilly Network Safari Bookshelf

Safari offers a solution that's better than e-books It's a virtuallibrary that lets you easily search thousands of top tech books,cut and paste code samples, download chapters, and find quickanswers when you need the most accurate, current information.Try it for free at http://safari.oreilly.com

Rasmus Lerdorf

I would like to acknowledge the large and wonderfully

boisterous PHP community, without which there would be noPHP today

Kevin Tatroe

Thanks to every individual who ever committed code to PHP orwho wrote a line of code in PHPyou all made PHP what it is

today

To my parents, who once purchased a small LEGO set for a longand frightening plane trip, beginning an obsession with

creativity and organization that continues to relax and inspire

Finally, a heaping second spoonful of gratitude to Jennifer andHadden, who continue to inspire and encourage me even as Ipound out words and code every day

Peter MacIntyre

I would first like to praise the Lord of Hosts who gives me thestrength to face each day He created electricity through which Imake my livelihood; thanks and praise to Him for this totallyunique and fascinating portion of His creation

Closer to home, I would like to thank Rasmus for the initial (andcontinuing) efforts behind this great language called PHP I have

start to finish

I would also like to thank my friends Mike Burns and Ian Morse,who performed the almost thankless job of doing the technicalediting on this book My hat goes off to you boththanks a lot!

And finally to all those at O'Reilly who so often go unmentionedIdon't know all your names, but I know what you have to do tomake a book like this finally make it to the bookshelves Theediting, graphics work, layout, planning, marketing, and so onall has to be done, and I appreciate your work toward this end

Dedication

I would like to dedicate my portions of this book to my

wonderful wife, Dawn Etta Riley She has been supportive of me

in my personal endeavors, and although some of them don'tpay off, she still supports my efforts of the ones that do I loveyou, Dawn, and look forward to the teenage-free years withyou To our children, too, I would like to dedicate this effort:Daniel Tomas Walker, Charity Margaret Marie MacIntyre, MichaelPeter Walker, and Simon Peter MacIntyre (just to get their

names in print)

PHP is a simple yet powerful language designed for creatingHTML content This chapter covers essential background on thePHP language It describes the nature and history of PHP; whichplatforms it runs on; and how to download, install, and

configure it This chapter ends by showing you PHP in action,with a quick walkthrough of several PHP programs that illustratecommon tasks, such as processing form data, interacting with adatabase, and creating graphics

PHP can be used in three primary ways:

Server-side scripting

PHP was originally designed to create dynamic web content,and it is still best suited for that task To generate HTML,you need the PHP parser and a web server to send the

documents PHP has also become popular for generatingXML documents, graphics, Flash animations, PDF files, andmore

Command-line scripting

PHP can run scripts from the command line, much like Perl,awk, or the Unix shell You might use the command-linescripts for system administration tasks, such as backup andlog parsing

Client-side GUI applications

blown, cross-platform GUI applications in PHP

Using PHP-GTK (http://gtk.php.net), you can write full-In this book, we'll concentrate on the first item, using PHP todevelop dynamic web content

PHP runs on all major operating systems, from Unix variantsincluding Linux, FreeBSD, and Solaris to Windows and Mac OS

X It can be used with all leading web servers, including

The language is very flexible For example, you aren't limited tooutputting just HTML or other text filesany document formatcan be generated PHP has built-in support for generating PDFfiles, GIF, JPG, and PNG images, and Flash movies

One of PHP's most significant features is its wide-ranging

support for databases PHP supports all major databases

(including MySQL, PostgreSQL, Oracle, Sybase, and ODBC-compliant databases), and even many obscure ones With PHP,creating web pages with dynamic content from a database isremarkably simple

Finally, PHP provides a library of PHP code to perform commontasks, such as database abstraction, error handling, and so on,with the PHP Extension and Application Repository (PEAR)

PEAR is a framework and distribution system for reusable PHPcomponents You can find out more about it at

http://pear.php.net

Logging accesses to your pages in your own private log files Real-time viewing of log information

Performing server-side includes without needing server support for it Ability to not log accesses from certain domains (ie your own)

Newsgroups: comp.infosystems.www.authoring.cgi

Password protect your pages, or restrict access based on the refering URL plus many other options

Thomas Boutell's GD library is supported through an easy-to-use set of tags

PHP 3.0 is available for free download in source form and binaries for several platforms at http://www.php.net/

The PHP Development Team is an international group of programmers who lead the open development of PHP and related projects

Figure 1-1 shows the growth of PHP as measured by the usagenumbers collected by Netcraft (http://www.netcraft.com) sinceJanuary 2000 This figure shows the total number of unique IPaddresses that report they are using Apache with the PHP

module enabled (PHP: 19,720,597 Domains, 1,310,181 IP

Addresses) The slight dip at the end of 2001 reflects the

demise of a number of dot-coms that disappeared from theWeb The overall number of servers that Netcraft found alsowent down for the first time during this period You can see anupdate of this chart for yourself at any time by accessing thisweb address: http://www.php.net/usage.php

Figure 1-1 The growth of PHP usage since 2000

PHP is available for many operating systems and platforms Themost common setup, however, is to use PHP as a module forthe Apache web server on a Unix machine This section brieflydescribes how to install Apache with PHP If you're interested inrunning PHP on Windows, see Chapter 15, which explains many

of your options for that operating system

To install Apache with PHP, you'll need a Unix machine with anANSI-compliant C compiler, and around 10 MB of available diskspace for source and object files You'll also need Internet

access to fetch the source code for PHP and Apache

Start by downloading the source distributions of PHP and

Apache The latest files are always available from the web sitesfor the respective tools Since there are so many options oninstallation , we are showing here the generic installation

instructions for a Linux server as shown on the PHP web site athttp://ca3.php.net/manual/en/install.unix.php You will have toreplace the xxx signifier in the following steps with the version ofthe software that you choose to install

Although Apache has a Version 2.x you may find that it is more adept

at serving PHP with Version 1.3.xx, so generally we will be using the 1.3.xx version throughout this book.

13 Set up your php.ini file:

cp php.ini-dist /usr/local/lib/php.ini

You may edit your ini file to set PHP options If you prefer your php.ini in another location, use with-config-file-