Drupal 7 Module Development

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Node Access Out-of-the-box, Drupal is a great system for creating and managing content. Users can log in and create content. Proper use of roles and permissions allows site editors to review some or all of a site's content. Site visitors can read published posts. But what happens if you want all site visitors to view some content, but only registered users to view a select list of restricted content? If, for example, your site requires paid registration to view in-depth articles about how to build Drupal web sites, the basic permissions provided by Drupal are not enough. There are cases where you need more advanced rules regarding which of the users (or groups of users) can create, view, edit, and delete content. To enable these rules, Drupal provides a Node Access system. Node Access provides an API for determining the grants, or permissions, that a user has for each node. By understanding how these grants work, a module developer can create and enforce complex access rules. In Drupal 7, any module may declare node access rules. This is a change from the earlier versions, and it provides some of the most powerful tools for Drupal development. In this chapter, we will cover: • Node Access compared to user_access() and other permission checks • How Drupal grants node permissions • The node_access() function • hook_node_access() compared to {node_access} • Controlling permissions to create content • Using hook_node_access() • When to write a Node Access module
Node Access • The {node_access} table and its role • Defining your module's access rules • Using hook_node_access_records() • Using hook_node_grants() • Rebuilding the {node_access} table • Modifying the behavior of other modules • Using hook_node_access_records_alter() • Using hook_node_grants_alter() • Testing and debugging your module • Using Devel Node Access Node Access compared to user_access() and other permission checks Unlike user_access(), using the Node Access system is not a simple case of implementing a specific permission check before executing your code. As we saw in the last chapter, user_access() determines what code may be executed for a specific user under a given set of conditions. Drupal's Node Access system is similar, but must account for variable conditions within a given set of nodes. For example, certain users may be allowed to edit any Basic page content but not allowed to edit any Article content. This condition means that Drupal must be able to distinguish among different properties of each node. The Node Access API is a series of interrelated functions that provide a consistent programming interface for making these types of access checks. Due to the flexible nature of Drupal however, there are multiple ways to define and implement node access control mechanisms. How Drupal grants node permissions As we mentioned in the introduction, there are four fundamental operations that affect nodes: Create, View, Update and Delete. Collectively, these are referred to as CRUD (where View is replaced by Read). When dealing with nodes, it is vital to know which operation is being performed. [ 242 ]
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www.allitebooks.com
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Drupal 7 Module Development Copyrig
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Foreword Drupal has its roots in th
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About the Authors Matt Butcher is a
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Larry Garfield is a Senior Architec
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John Albin Wilkins has been a web d
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Jojodae Ganesh Sivaji has been invo
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Why Subscribe? • Fully searchable
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Table of Contents Tools for develop
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Table of Contents A shortcut for sy
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Table of Contents Using hook_node_a
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Table of Contents Creating a task 3
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Preface Chapter 5, Building an Admi
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Preface The system for handling thi
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Developing for Drupal 7 Drupal is a
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However, what we do want to start w
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The Operating System Chapter 1 Wind
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Chapter 1 Drupal core is the founda
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Chapter 1 The database We have take
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Chapter 1 The responsibility of the
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Chapter 1 While one could imagine t
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Chapter 1 We assume that you have y
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Chapter 1 The following are a few o
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Creating Your First Module We are g
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Creating Your First Module As obvio
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Creating Your First Module By Drupa
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Creating Your First Module The next
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Creating Your First Module When Dru
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Creating Your First Module Doxygen-
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Creating Your First Module The help
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Creating Your First Module Drupal s
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Creating Your First Module Finally,
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Creating Your First Module Here's o
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Creating Your First Module ); } } r
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Creating Your First Module Not in J
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Creating Your First Module There ar
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Creating Your First Module The exam
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Creating Your First Module Setting
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Creating Your First Module } ); pub
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Creating Your First Module You migh
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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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Page 228 and 229: Chapter 7 We can, of course, have m
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Page 232 and 233: [ 209 ] Chapter 7 Now look at that
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Page 236 and 237: Chapter 8 The preceding code checks
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Page 250 and 251: [ 227 ] Chapter 8 Enabling permissi
Page 252 and 253: Chapter 8 } $permissions = array( '
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Page 256 and 257: Chapter 8 Running access checks on
Page 258 and 259: Chapter 8 Handling AJAX callbacks s
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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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