Advanced PHP Programming

Advanced PHP

Programming

Advanced PHP

Programming

Apractical guide to developing large-scale Web sites and applications with PHP 5

George Schlossnagle

DEVELOPER’S

L IBRARY

Sams Publishing, 800 East 96th Street, Indianapolis, Indiana 46240 USA

Advanced PHP Programming

Copyright ♥ 2004 by Sams Publishing

All rights reserved. No part of this book shall be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without written permission from the publisher. No patent liability is assumed with respect to the use of the information contained herein. Although every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions. Nor is any liability assumed for damages resulting from the use of the information contained herein.

International Standard Book Number: 0-672-32561-6

Library of Congress Catalog Card Number: 2003100478

Printed in the United States of America

First Printing: March 2004

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Contents v

Contents at a Glance

Introduction

IImplementation and Development Methodologies

1 Coding Styles

2Object-Oriented Programming Through Design Patterns

3 Error Handling

4 Implementing with PHP:Templates and the Web

5 Implementing with PHP: Standalone Scripts

6 Unit Testing

7 Managing the Development Environment

8 Designing a Good API

II Caching

9 External Performance Tunings

10Data Component Caching

11Computational Reuse

III Distributed Applications

12Interacting with Databases

13User Authentication and Session Security

14Session Handling

15Building a Distributed Environment

16RPC: Interacting with Remote Services

vi Contents

IV Performance

17Application Benchmarks:Testing an Entire Application

18Profiling

19Synthetic Benchmarks: Evaluating Code Blocks and Functions

V Extensibility

20PHP and Zend Engine Internals

21Extending PHP: Part I

22Extending PHP: Part II

23Writing SAPIs and Extending the Zend Engine Index

Contents vii

Table of Contents

Introduction 1

IImplementation and Development Methodologies

1 Coding Styles	9
Choosing a Style That Is Right for You 10
Code Formatting and Layout					10
Indentation	10
Line Length	13
Using Whitespace		13
SQL Guidelines		14
Control Flow Constructs				14
Naming Symbols	19
Constants and Truly Global Variables 21
Long-Lived Variables			22
Temporary Variables			23
Multiword Names 24
Function Names		24
Class Names	25
Method Names		25
Naming Consistency			25
Matching Variable Names to Schema Names						26
Avoiding Confusing Code			27
Avoiding Using Open Tags				27
Avoiding Using echo to Construct HTML						27
Using Parentheses Judiciously					28
Documentation 29
Inline Comments		29
API Documentation			30
Further Reading	35

viii Contents

2Object-Oriented Programming Through Design Patterns 37

Introduction to OO Programming 38
Inheritance		40
Encapsulation			41
Static (or Class) Attributes and Methods 41
Special Methods 42
A Brief Introduction to Design Patterns 44
The Adaptor Pattern				44
The Template Pattern				49
Polymorphism			50
Interfaces and Type Hints 52
The Factory Pattern				54
The Singleton Pattern				56
Overloading	58
SPL	63
_ _call() 68
_ _autoload()			70
Further Reading		71

3 Error Handling		73
Handling Errors	75
Displaying Errors			76
Logging Errors		77
Ignoring Errors		78
Acting On Errors			79
Handling External Errors			80
Exceptions 83
Using Exception Hierarchies				86
A Typed Exceptions Example				88
Cascading Exceptions 94
Handling Constructor Failure				97
Installing a Top-Level Exception Handler 98
Data Validation		100
When to Use Exceptions			104
Further Reading	105

Contents ix

4 Implementing with PHP: Templates and the Web 107

Smarty 108

Installing Smarty 109

Your First Smarty Template: Hello World! 110

Compiled Templates Under the Hood 111

Smarty Control Structures	111
Smarty Functions and More	114
Caching with Smarty 117
Advanced Smarty Features	118

Writing Your Own Template Solution 120

Further Reading 121

5Implementing with PHP: Standalone Scripts 123

Introduction to the PHP Command-Line Interface (CLI) 125

Handling Input/Output (I/O)		125
Parsing Command-Line Arguments			128
Creating and Managing Child Processes				130
Closing Shared Resources		131
Sharing Variables 132
Cleaning Up After Children			132
Signals 134
Writing Daemons	138
Changing the Working Directory				140
Giving Up Privileges 140
Guaranteeing Exclusivity		141
Combining What You’ve Learned: Monitoring
Services 141
Further Reading	150

6 Unit Testing	153
An Introduction to Unit Testing		154
Writing Unit Tests for Automated Unit
Testing	155
Writing Your First Unit Test		155
Adding Multiple Tests 156