Pro Drupal Development (eBook)

John K. VanDyk has been a Drupal developer since 2004. In 2005, he organized the first Drupal conference in Antwerp, Belgium, with Drupal founder Dries Buytaert. John has contributed several modules to Drupal including the actions, workflow, publish, subscribe, and pubcookie modules and has been instrumental in the design of Drupal's Content Construction Kit. John's day job is as an entomology professor and systems analyst at Iowa State University, where he teaches undergraduate courses about insects. In his spare time, when not hacking on Drupal, John enjoys squash hunting and raising children.

Contents at a Glance 5
Contents 7
Foreword 25
About the Author 26
About the Technical Reviewer 27
Acknowledgments 28
Introduction 29
How Drupal Works 30
What Is Drupal? 30
Technology Stack 30
Core 31
Administrative Interface 32
Modules 32
Hooks 33
Themes 34
Nodes 34
Blocks 35
File Layout 35
Serving a Request 37
Summary 40
Writing a Module 41
Creating the Files 41
Implementing a Hook 43
Adding Module- Specific Settings 44
Adding the Data Entry Form 47
Defining Your Own Administration Section 55
Presenting a Settings Form to the User 57
Validating User- Submitted Settings 59
Storing Settings 60
Further Steps 62
Summary 62
Hooks, Actions, and Triggers 63
Understanding Events and Triggers 63
Understanding Actions 65
Using the Context in Actions 75
Examining the Context 79
How Actions Are Stored 80
Calling an Action Directly with actions_ do() 81
Defining Your Own Triggers with hook_ hook_ info() 82
Adding Triggers to Existing Hooks 84
Summary 86
The Menu System 87
Callback Mapping 87
Menu Nesting 97
Access Control 98
Title Localization and Customization 99
Wildcards in Menu Items 103
Altering Menu Items from Other Modules 108
Altering Menu Links from Other Modules 110
Kinds of Menu Items 110
Common Tasks 111
Using menu. module 115
Common Mistakes 115
Summary 116
Working with Databases 117
Defining Database Parameters 117
Understanding the Database Abstraction Layer 117
Connecting to the Database 119
Performing Simple Queries 120
Retrieving Query Results 122
The Schema API 123
Inserts and Updates with drupal_ write_ record() 134
Exposing Queries to Other Modules with hook_ db_ rewrite_ sql() 136
Connecting to Multiple Databases Within Drupal 139
Using a Temporary Table 140
Writing Your Own Database Driver 140
Summary 141
Working with Users 143
The $ user Object 143
Introduction to hook_ user() 146
The User Registration Process 149
The Login Process 152
External Login 157
Summary 164
Working with Nodes 165
So What Exactly Is a Node? 165
Not Everything Is a Node 168
Creating a Node Module 168
How Nodes Are Stored 185
Creating a Node Type with CCK 186
Restricting Access to Nodes 187
Summary 191
The Theme System 192
Theme System Components 192
Installing a Theme 195
Building a PHPTemplate Theme 196
Understanding Template Files 203
Advanced Drupal Theming 221
Summary 228
Working with Blocks 229
What Is a Block? 229
Block Configuration Options 230
Block Placement 232
Defining a Block 232
Building a Block 236
Enabling a Block When a Module Is Installed 244
Block Visibility Examples 244
Summary 245
The Form API 246
Understanding Form Processing 246
Creating Basic Forms 254
Form API Properties 277
Summary 298
Manipulating User Input: The Filter System 299
Filters 299
Filters and Input Formats 300
Creating a Custom Filter 306
Protecting Against Malicious Data 312
Summary 313
Searching and Indexing Content 314
Building a Custom Search Page 314
Using the Search HTML Indexer 322
Summary 331
Working with Files 332
How Drupal Serves Files 332
PHP Settings 334
Media Handling 335
File API 336
Summary 349
Working with Taxonomy 350
What Is Taxonomy? 350
Kinds of Taxonomy 354
Viewing Content by Term 356
Storing Taxonomies 358
Module- Based Vocabularies 360
Common Tasks 363
Taxonomy Functions 365
Additional Resources 371
Summary 371
Caching 372
Knowing When to Cache 372
How Caching Works 373
How Caching Is Used Within Drupal Core 374
Summary 387
Sessions 388
What Are Sessions? 388
Usage 389
Session- Related Settings 390
Storage 392
Session Life Cycle 393
Session Conversations 395
Common Tasks 396
Summary 398
Using jQuery 399
What Is jQuery? 399
The Old Way 400
How jQuery Works 401
jQuery Within Drupal 403
Building a jQuery Voting Widget 415
Next Steps 427
Summary 427
Localization and Translation 428
Enabling the Locale Module 428
User Interface Translation 428
Starting a New Translation 441
Installing a Language Translation 445
Right- to- Left Language Support 447
Language Negotiation 448
Content Translation 453
Localization- and Translation- Related Files 458
Additional Resources 458
Summary 459
XML-RPC 460
What Is XML- RPC? 460
Prerequisites for XML- RPC 460
XML- RPC Clients 461
A Simple XML- RPC Server 466
Built- In XML- RPC Methods 470
Summary 472
Writing Secure Code 473
Handling User Input 473
Handling URLs Securely 480
Making Queries Secure with db_ query() 481
Keeping Private Data Private with db_ rewrite_ sql() 485
Dynamic Queries 486
Permissions and Page Callbacks 487
Cross- Site Request Forgeries ( CSRF) 488
File Security 488
Encoding Mail Headers 491
Protecting cron. php 492
SSL Support 492
Stand- Alone PHP 493
AJAX Security 494
Form API Security 494
Protecting the Superuser Account 495
Using eval() 496
Summary 496
Development Best Practices 497
Coding Standards 497
PHP Comments 503
Checking Your Coding Style Programmatically 507
Finding Your Way Around Code with egrep 508
Taking Advantage of Version Control 510
Creating and Applying Patches 520
Maintaining a Module 521
Mixing SVN with CVS for Project Management 538
Testing and Developing Code 539
The Module Builder Module 542
Application Profiling and Debugging 542
Summary 544
Optimizing Drupal 546
Finding the Bottleneck 546
Drupal- Specific Optimizations 555
Architectures 561
Summary 564
Installation Profiles 565
Where Profiles Are Stored 565
How Installation Profiles Work 566
Summary 589
Database Table Reference 590
access ( user module) 590
accesslog ( statistics module) 590
actions ( trigger module) 591
actions_ aid ( trigger module) 591
aggregator_ category ( aggregator module) 592
aggregator_ category_ feed ( aggregator module) 592
aggregator_ category_ item ( aggregator module) 592
aggregator_ feed ( aggregator module) 592
aggregator_ item ( aggregator module) 593
authmap ( user module) 593
batch ( batch. inc) 594
blocks ( block module) 594
blocks_ roles ( block module) 595
book ( book module) 595
boxes ( block module) 596
cache 596
cache_ block ( block module) 596
cache_ filter ( filter module) 597
cache_ form 597
cache_ menu 598
cache_ page 598
cache_ update 599
comments ( comment module) 599
contact ( contact module) 600
files ( upload module) 600
filter_ formats ( filter module) 601
filters ( filter module) 601
flood ( contact module) 601
forum ( forum module) 602
history ( node module) 602
languages ( locale module) 602
locales_ source ( locale module) 603
locales_ target ( locale module) 603
menu_ custom ( menu module) 603
menu_ links ( menu module) 604
menu_ router 605
node ( node module) 606
node_ access ( node module) 607
node_ comment_ statistics ( comment module) 608
node_ counter ( statistics module) 608
node_ revisions ( node module) 608
node_ type ( node module) 609
openid_ association ( openid module) 610
permission ( user module) 610
poll ( poll module) 611
poll_ choices ( poll module) 611
poll_ votes ( poll module) 611
profile_ fields ( profile module) 612
profile_ values ( profile module) 612
role ( user module) 613
search_ dataset ( search module) 613
search_ index ( search module) 613
search_ node_ links ( search module) 614
search_ total ( search module) 614
sessions 614
system 615
term_ data ( taxonomy module) 616
term_ hierarchy ( taxonomy module) 616
term_ node ( taxonomy module) 616
term_ relation ( taxonomy module) 616
term_ synonym ( taxonomy module) 617
trigger_ assignments ( trigger module) 617
upload ( upload module) 617
url_ alias ( path module) 618
users ( user module) 618
users_ roles ( users) 619
variable 619
vocabulary ( taxonomy module) 620
vocabulary_ node_ types ( taxonomy module) 620
watchdog ( dblog module) 621
Resources 622
Code 622
Handbooks 623
Forums 623
Mailing Lists 623
User Groups and Interest Groups 625
Internet Relay Chat 625
Videocasts 626
Weblogs 626
Conferences 626
Contribute 627
Index 628