Drupal 7 Module Development

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Creating Your First Module The focus of this chapter is module creation. In the last chapter we surveyed Drupal's architecture advanced. We learned about the basic features and subsystems. We also saw some tools available for development. Now we are going to begin coding. Here are some of the important topics that we will cover in this chapter: • Starting a new module • Creating .info files to provide Drupal with module information • Creating .module files to store Drupal code • Adding new blocks using the Block Subsystem • Using common Drupal functions • Formatting code according to the Drupal coding standards • Writing an automated test for Drupal By the end of this chapter, you should have the foundational knowledge necessary for building your own module from scratch. Our goal: a module with a block In this chapter we are going to build a simple module. The module will use the Block Subsystem to add a new custom block. The block that we add will simply display a list of all of the currently enabled modules on our Drupal installation. The block subsystem was introduced in the previous chapter alongside other important Drupal subsystems.
Creating Your First Module We are going to divide this task of building a new module into the three parts: • Create a new module folder and module files • Work with the Block Subsystem • Write automated tests using the SimpleTest framework included in Drupal We are going to proceed in that order for the sake of simplicity. One might object that, following agile development processes, we ought to begin by writing our tests. This approach is called Test-driven Development (TDD), and is a justly popular methodology. Agile software development is a particular methodology designed to help teams of developers effectively and efficiently build software. While Drupal itself has not been developed using an agile process, it does facilitate many of the agile practices. To learn more about agile, visit http://agilemanifesto.org/. However, our goal here is not to exemplify a particular methodology, but to discover how to write modules. It is easier to learn module development by first writing the module, and then learn how to write unit tests. It is easier for two reasons: • SimpleTest (in spite of its name) is the least simple part of this chapter. It will have double the code-weight of our actual module. • We will need to become acquainted with the APIs we are going to use in development before we attempt to write tests that assume knowledge of those APIs. In regular module development, though, you may certainly choose to follow the TDD approach of writing tests first, and then writing the module. Let's now move on to the first step of creating a new module. Creating a new module Creating Drupal modules is easy. How easy? Easy enough that over 5,000 modules have been developed, and many Drupal developers are even PHP novices! In fact, the code in this chapter is an illustration of how easy module coding can be. We are going to create our first module with only one directory and two small files. [ 26 ]
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
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Page 32 and 33: However, what we do want to start w
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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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