Drupal 7 Module Development

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However, what we do want to start with, is a quick overview of the technologies utilized in Drupal. Chapter 1 PHP Drupal is written in the PHP programming language (http://php.net). PHP is a widely supported, multi-platform, web-centric scripting language. Since Drupal is written in PHP, this book is largely focused on PHP development. One specific piece of information should be made explicit: As of Drupal 7, the minimum PHP version is PHP 5.2 (as of this writing, the current version of PHP is 5.3.3). Prior versions of Drupal included PHP 4.x support, but this is no longer the case. Another thing worth mentioning is the style of PHP coding that Drupal uses. While many PHP applications are now written using Object Oriented Programming, Drupal does not follow suit. For many reasons, some historical, some practical, Drupal is largely written using procedural programming. Rather than relying strongly on classes and interfaces, Drupal modules are composed of collections of functions. Before anyone jumps to conclusions, though, we would like to make a few qualifications on what we've just said: • Drupal frequently uses objects • Drupal does have certain subsystems that are object-oriented • Many Drupal modules are substantially object-oriented • Drupal makes frequent use of design patterns, for it is certainly the case that procedural code can use design patterns too While the majority of this book uses procedural coding strategies, you will encounter OOP here and there. If you are not familiar with object oriented conventions and coding styles, don't worry. We will explain these pieces as we go. Databases and MySQL In the past, Drupal has supported two databases: MySQL and PostgreSQL. Drupal 7 has moved beyond this. Drupal now uses the powerful PDO (PHP Data Objects) library that is standard in PHP 5. This library is an abstraction layer that allows developers to support numerous databases including MySQL, PostgreSQL, SQLite, MariaDB, and many, many others. While Drupal does testing on only a few specific databases (namely, MySQL, PostgreSQL, and now SQLite), it is possible to move beyond these to SQL Server, Oracle, DB2, and others. [ ]
Developing for Drupal 7 However, for the sake of size and readability, we have focused our examples on MySQL. We believe that our SQL should run on MariaDB, PostgreSQL, and SQLite without modification, but we have not made any attempt to test against other databases. If you find a bug, we'd appreciate hearing about it. Packt Publishing tracks errata on their website (http://packtpub.com), and you can submit errors that you find through the form you find there. Drupal provides a database API along with some SQL coding conventions (such as "don't use LIMIT in your SQL"). The intent of these is to combine code and convention to make it as easy as possible to write portable code. Thus, we not only illustrate the API throughout this book, but we also focus on writing SQL statements that comply with standard Drupal conventions. HTML, CSS, and JavaScript The de facto web data format is HTML (HyperText Markup Language) styled with CSS (Cascading Style Sheets). Client-side interactive components are scripted with JavaScript. As Drupal developers, we will encounter all three of these technologies in this book. While you needn't be a JavaScript ninja to understand the code here, you will get the most from this book if you are comfortable with these three technologies. Other technologies The Internet thrives on change, it seems, and there are many other web technologies that have become common. Here and there, we will mention technologies such as RSS (Really Simple Syndication), XML (eXtensible Markup Language), XML-RPC, and others. However, these are all of secondary importance to us. While Drupal offers support for many of these things, using them is not integral to module or theme development. The web server Apache has long been the predominant web server, but it is by no means the only server. While Drupal was originally written with Apache in mind, many other web servers (including IIS, LigHTTPD, and nginx) can run Drupal. We do not explicitly cover the web server layer anywhere here, primarily because development rarely requires working at that low level. However, Drupal expects a fair amount of processing from the web server layer, including handling of URL rewriting. [ 10 ]
Page 1 and 2: www.allitebooks.com
Page 3 and 4: Drupal 7 Module Development Copyrig
Page 5 and 6: Foreword Drupal has its roots in th
Page 7 and 8: About the Authors Matt Butcher is a
Page 9 and 10: Larry Garfield is a Senior Architec
Page 11 and 12: John Albin Wilkins has been a web d
Page 13 and 14: Jojodae Ganesh Sivaji has been invo
Page 15 and 16: Why Subscribe? • Fully searchable
Page 17 and 18: Table of Contents Tools for develop
Page 19 and 20: Table of Contents A shortcut for sy
Page 21 and 22: Table of Contents Using hook_node_a
Page 23 and 24: Table of Contents Creating a task 3
Page 25 and 26: Preface Chapter 5, Building an Admi
Page 27 and 28: Preface The system for handling thi
Page 30 and 31: Developing for Drupal 7 Drupal is a
Page 34 and 35: The Operating System Chapter 1 Wind
Page 36 and 37: Chapter 1 Drupal core is the founda
Page 38 and 39: Chapter 1 The database We have take
Page 40 and 41: Chapter 1 The responsibility of the
Page 42 and 43: Chapter 1 While one could imagine t
Page 44 and 45: Chapter 1 We assume that you have y
Page 46: Chapter 1 The following are a few o
Page 49 and 50: Creating Your First Module We are g
Page 51 and 52: Creating Your First Module As obvio
Page 53 and 54: Creating Your First Module By Drupa
Page 55 and 56: Creating Your First Module The next
Page 57 and 58: Creating Your First Module When Dru
Page 59 and 60: Creating Your First Module Doxygen-
Page 61 and 62: Creating Your First Module The help
Page 63 and 64: Creating Your First Module Drupal s
Page 65 and 66: Creating Your First Module Finally,
Page 67 and 68: Creating Your First Module Here's o
Page 69 and 70: Creating Your First Module ); } } r
Page 71 and 72: Creating Your First Module Not in J
Page 73 and 74: Creating Your First Module There ar
Page 75 and 76: Creating Your First Module The exam
Page 77 and 78: Creating Your First Module Setting
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Creating Your First Module The repo
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Drupal’s Theme Layer This book is
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Drupal’s Theme Layer There are ac
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Drupal’s Theme Layer Theme engine
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Drupal’s Theme Layer Preprocess f
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Drupal’s Theme Layer A Drupal the
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Drupal’s Theme Layer The theme()
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Drupal’s Theme Layer Now, if you
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Drupal’s Theme Layer A similar pr
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Drupal’s Theme Layer Now, that wa
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Drupal’s Theme Layer • #suffix:
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Drupal’s Theme Layer Two powerful
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Drupal’s Theme Layer 'menu_tree__
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Drupal’s Theme Layer If a functio
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Drupal’s Theme Layer We've also s
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Drupal’s Theme Layer Summary You'
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Theming a Module After all, if you
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Theming a Module * Enables a single
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Theming a Module * First draft! * *
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Theming a Module Theming a Drupal b
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Theming a Module Converting a theme
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Theming a Module if (is_array($elem
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Theming a Module Notice that the .b
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Theming a Module } $block['content'
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Theming a Module } 'variables' => a
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Theming a Module } // Theme the use
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Theming a Module // Create links fo
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Theming a Module } // Load the acco
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Theming a Module * - $user: The use
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Theming a Module Summary In this ch
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Building an Admin Interface Startin
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Building an Admin Interface $items[
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Building an Admin Interface 'access
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Building an Admin Interface Each ar
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Building an Admin Interface Other p
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Building an Admin Interface Each el
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Building an Admin Interface Drupal
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Building an Admin Interface This is
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Building an Admin Interface Form su
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Building an Admin Interface A short
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Building an Admin Interface } retur
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Building an Admin Interface PHP mai
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Building an Admin Interface Impleme
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Building an Admin Interface Debuggi
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Building an Admin Interface This te
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Working with Content Drupal 7 intro
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Chapter 6 The Schema API allows dat
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'fields' => array( 'aid' => array(
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Chapter 6 'fieldable' => TRUE, 'ent
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Chapter 6 The return value from the
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Chapter 6 In our case, we defined t
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Chapter 6 Most entity operations in
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[ 165 ] Chapter 6 This callback sim
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Chapter 6 This page will simply gen
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Chapter 6 This hook defines a new f
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Submit callback The submit callback
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Chapter 6 // Save the initial revis
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Chapter 6 Master/slave database con
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Chapter 6 array($artwork->aid => $a
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Chapter 6 'access arguments' => arr
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Chapter 6 } foreach ($artworks as $
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Creating New Fields In the last cha
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Chapter 7 Although an advanced topi
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Chapter 7 The most important magic
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Chapter 7 } } '#type' => 'select',
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Chapter 7 Exposing fields to the Fo
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Chapter 7 $element['width'] = array
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Chapter 7 if ($widget['type'] == 'd
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Chapter 7 } return; 'field_ui_field
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Chapter 7 } function theme_dimfield
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Chapter 7 } '@height' => $item['hei
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Chapter 7 } else if ($settings['uni
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Chapter 7 We can, of course, have m
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Chapter 7 To demonstrate how entity
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[ 209 ] Chapter 7 Now look at that
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Drupal Permissions and Security Per
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Chapter 8 The preceding code checks
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Chapter 8 If we had accidentally ru
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Chapter 8 The user_access() functio
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In the first case, Are we looking a
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Chapter 8 Declaring your own access
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} Chapter 8 'page callback' => 'exa
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Chapter 8 if (!flood_is_allowed('co
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[ 227 ] Chapter 8 Enabling permissi
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Chapter 8 } $permissions = array( '
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Chapter 8 This approach is the prop
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Chapter 8 Running access checks on
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Chapter 8 Handling AJAX callbacks s
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Chapter 8 As a result, we cannot tr
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Chapter 8 This allows us to pass a
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Node Access Out-of-the-box, Drupal
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Chapter 9 The Node Access API allow
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* - "delete" * - "create" * @param
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Chapter 9 if (!user_access('access
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Chapter 9 } if (module_implements('
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Chapter 9 hook_node_access() is the
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Chapter 9 Note that the {node_acces
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Chapter 9 The basic permission 'cre
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Chapter 9 It is a good idea to writ
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Chapter 9 On node listing pages, th
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Chapter 9 Writing a complete node a
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• Can this user bypass node acces
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Chapter 9 For our test module, we w
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Chapter 9 When hook_node_access_rec
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Chapter 9 A few things to consider
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Chapter 9 Security considerations T
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Chapter 9 Rebuilding the {node_acce
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Chapter 9 Using the new hook_node_a
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Chapter 9 We may alter any element
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Chapter 9 } // Check anonymous user
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Chapter 9 // Check the permission.
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Chapter 9 The key to Devel Node Acc
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Chapter 9 In the preceding case, th
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JavaScript in Drupal JavaScript is
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Chapter 10 Adding JavaScript and CS
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Chapter 10 When a JavaScript librar
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The following code adds a system CS
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Chapter 10 The second argument can
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Chapter 10 From here onwards, when
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Chapter 10 If a renderable array is
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Chapter 10 Drupal specific JavaScri
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Chapter 10 There are three ways var
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Chapter 10 AJAX helpers Included in
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The callback function hello_world_s
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Chapter 10 Once the response is set
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ajax_command_prepend To add content
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Working with Files and Images Drupa
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Chapter 11 It is very important tha
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Chapter 11 In order to open files f
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Chapter 11 Stream wrappers If you'v
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Chapter 11 In some cases you may no
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Chapter 11 A read-only stream wrapp
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Chapter 11 } 'type' => STREAM_WRAPP
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Chapter 11 For full details of thes
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Chapter 11 After this setup, we sta
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Chapter 11 This is all very cool, b
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Chapter 11 This is where you can st
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Chapter 11 • form callback: If yo
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Chapter 11 Finally we can make the
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Chapter 11 Pretty cool right? Howev
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Chapter 11 As you can see, there is
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Installation Profiles This chapter
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Chapter 12 Profile modules and them
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Enabling modules Just like modules
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Chapter 12 • display_name: A huma
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Next, let's create a form to enter
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Chapter 12 Notice that $install_sta
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Chapter 12 Here, the task that sets
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Chapter 12 Each row being added to
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Chapter 12 // URL filter. 'filter_u
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Chapter 12 'locale' => 'en', ), //
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Database Access Although Drupal 7 h
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Appendix A Result objects The retur
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Appendix A The join() methods all r
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[ 369 ] Appendix A The db_insert()
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Appendix A A Merge query says, in e
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Appendix A Slave servers Drupal als
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Security Throughout this book, we h
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Filtering The following guidelines
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First, whenever we write a query ag
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Appendix B There are both RSS feeds
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ajax_command_alert command 309 ajax
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Drupal, subsytems blocks 20 code te
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form handling 229 forms access chec
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K key() method 371 L label property
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evision handling 175 revisions hand
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U unit test 49 update queries 370 u
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Drupal 7 ISBN: 978-1-84951-286-2 Pa
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