Pro Drupal Development, Second Edition

706 Pages·2008·11.06 MB·English

by  John K. VanDyk

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Books for professionals By professionals® The eXperT’s Voice® in open source
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Pro Drupal Development,
DDrruuppaall 66!!
Pro
SeconD eDition
Pro
Dear Reader, D
Drupal is a powerful open source content management framework for creating
customized web sites. Building on its modular core, over time you can evolve a r
basic brochure-style site into a platform for driving cutting-edge services such
u Drupal
as social networking, mashups, and e-commerce, all within the same consis-
tent, integrated, and secure framework. Best of all, with Drupal’s fine-grained
permissions and revision support, editing web site content can be delegated to p
those who know it best—the users.
In Pro Drupal Development, Second Edition, I cover Drupal from the per- a
spective of someone knowledgeable in PHP who is looking for a way to quickly
understand the system and begin coding sophisticated Drupal applications as l
soon as possible. For that reason, I use an approach that is peppered with practi-
cal coding examples, big-picture flowcharts, and diagrams to help you visualize
D
how Drupal works. And I’ve included a chapter on best practices for Drupal
development to help you avoid common pitfalls. e
I have been using Drupal for over five years and have contributed to the Drupal Development
v
core as well as to numerous modules. During this time, though Drupal was designed
e
to be lean and modular, I’ve observed new developers struggling to understand
Drupal’s internals. This book should help make the learning curve less daunting and l
encourage talented developers to learn, use, and ultimately share in the benefits of o
one of the most vibrant and growing open source communities. p
John K. VanDyk, PhD m
e
Learn how to use the content management
n
THE APRESS ROADMAP framework to create powerful customized web sites
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companion eBook
Building Online
Pro Drupal Development,
Communities with Drupal,
Second Edition
phpBB, and WordPress SeconD
eDition SeconD eDition
Beginning PHP and PHP 5 Objects,
MySQL 5, Third Edition Patterns, and Practice
See last page for details
on $10 eBook version
Drupal 6
SOURCE CODE ONLINE V John K. VanDyk
a
www.apress.com ISBN 978-1-4302-0989-8 n
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y Foreword by Dries Buytaert,
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US $49.99 Drupal founder and project lead
Shelve in
PHP
User level: 9 781430 209898
Intermediate–Advanced
this print for content only—size & color not accurate spine = 1.324" 704 page count

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Pro Drupal
Development
Second Edition
John K. VanDyk
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Pro Drupal Development,Second Edition
Copyright © 2008 by John K.VanDyk
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,
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ISBN-13 (electronic): 978-1-4302-0990-4
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For the Great Architect
and to my incredibly patient wife and children
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Contents at a Glance
Foreword........................................................................xxv
About the Author................................................................xxvii
About the Technical Reviewer .....................................................xxix
Acknowledgments...............................................................xxxi
Introduction....................................................................xxxiii
nCHAPTER 1 HowDrupal Works..............................................1
nCHAPTER 2 Writing a Module ..............................................13
nCHAPTER 3 Hooks,Actions,and Triggers...................................35
nCHAPTER 4 The Menu System .............................................59
nCHAPTER 5 Working with Databases.......................................89
nCHAPTER 6 Working with Users...........................................115
nCHAPTER 7 Working with Nodes ..........................................137
nCHAPTER 8 The Theme System ...........................................165
nCHAPTER 9 Working with Blocks..........................................203
nCHAPTER 10 The FormAPI.................................................221
nCHAPTER 11 Manipulating User Input:The Filter System....................275
iv
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nCHAPTER 12 Searching and Indexing Content ..............................291
nCHAPTER 13 Working with Files............................................309
nCHAPTER 14 Working with Taxonomy ......................................327
nCHAPTER 15 Caching......................................................349
nCHAPTER 16 Sessions .....................................................365
nCHAPTER 17 Using jQuery..................................................377
nCHAPTER 18 Localization and Translation ..................................407
nCHAPTER 19 XML-RPC.....................................................439
nCHAPTER 20 Writing Secure Code..........................................453
nCHAPTER 21 Development Best Practices ..................................477
nCHAPTER 22 Optimizing Drupal ............................................527
nCHAPTER 23 Installation Profiles...........................................547
nAPPENDIX A Database Table Reference....................................573
nAPPENDIX B Resources....................................................605
nINDEX .......................................................................611
v
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Contents
Foreword........................................................................xxv
About the Author................................................................xxvii
About the Technical Reviewer .....................................................xxix
Acknowledgments...............................................................xxxi
Introduction....................................................................xxxiii
nCHAPTER 1 How Drupal Works...........................................1
WhatIs Drupal?..................................................1
Technology Stack ................................................1
Core............................................................2
Administrative Interface...........................................3
Modules.........................................................3
Hooks...........................................................4
Themes.........................................................5
Nodes ..........................................................5
Blocks ..........................................................6
File Layout ......................................................6
Serving a Request................................................8
The Web Server’s Role.......................................8
The BootstrapProcess .......................................9
Processing a Request.......................................10
Theming the Data ..........................................11
Summary.......................................................11
nCHAPTER 2 Writing a Module............................................13
Creating the Files................................................13
Implementing a Hook............................................15
Adding Module-Specific Settings..................................16
Adding the Data Entry Form.......................................19
Storing Data in a Database Table.............................22
Defining Your Own Administration Section..........................27
Presenting a Settings Form to the User.............................29
Validating User-Submitted Settings................................31
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viii nCONTENTS
Storing Settings.................................................32
Using Drupal’s variables Table ...............................33
Retrieving Stored Values with variable_get() ...................34
Further Steps...................................................34
Summary.......................................................34
nCHAPTER 3 Hooks, Actions, and Triggers ..............................35
Understanding Events and Triggers................................35
Understanding Actions...........................................37
The Trigger User Interface...................................37
Your First Action............................................39
Assigning the Action........................................41
Changing Which Triggers an Action Supports ..................41
Actions That Support Any Trigger.............................42
Advanced Actions ..........................................42
Using the Context in Actions......................................47
How the Trigger Module Prepares the Context..................47
Establishing the Context.....................................49
Examining the Context...........................................51
HowActions Are Stored..........................................52
The actions Table...........................................52
Action IDs .................................................53
Calling an Action Directly with actions_do().........................53
Defining Your Own Triggers with hook_hook_info()..................54
Adding Triggers to Existing Hooks .................................56
Summary.......................................................58
nCHAPTER 4 The Menu System...........................................59
Callback Mapping ...............................................59
Mapping URLs to Functions..................................59
Page Callback Arguments ...................................65
Menu Nesting...................................................69
Access Control..................................................70
Title Localization and Customization...............................71
Defining a Title Callback.....................................71
Title Arguments ............................................73
Wildcards in Menu Items.........................................75
Wildcards and Parameter Replacement........................77
Building Paths from Wildcards Using to_arg() Functions .........79