Drupal 7 Module Development

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So the t() function should always be given a literal string for its first argument. The third thing to note about the t() function is that it does more than translate strings. It offers a method of variable interpolation that is more secure than the usual method. In many PHP applications, you will see code like this: print "Welcome, $username."; The code above will replace $username with the value of the $username variable. This code leaves open the possibility that the value of $username contains data that will break the HTML in the output – or worse, that it will open an avenue for a malicious user to inject JavaScript or other code into the output. Chapter 2 The t() function provides an alternate, and more secure, method for replacing placeholders in text with a value. The function takes an optional second argument, which is an associative array of items that can be substituted. Here's an example that replaces the the previous code: $values = array('@user' => $username); print t('Welcome, @user', $values); In the previous case, we declare a placeholder named @user, the value of which is the value of the $username variable. When the t() function is executed, the mappings in $values are used to substitute placeholders with the correct data. But there is an additional benefit: these substitutions are done in a secure way. If the placeholder begins with @, then before it inserts the value, Drupal sanitizes the value using its internal check_plain() function (which we will encounter many times in subsequent chapters). If you are sure that the string doesn't contain any dangerous information, you can use a different symbol to begin your placeholder: the exclamation mark (!). When that is used, Drupal will simply insert the value as is. This can be very useful when you need to insert data that should not be translated: $values = array('!url' => 'http://example.com'); print t('The website can be found at !url', $values); In this case, the URL will be entered with no escaping. We can do this safely only because we already know the value of URL. It does not come from a distrusted user. [ 41 ]
Creating Your First Module Finally, there is a third placeholder decorator: the percent sign (%) tells Drupal to escape the code and to mark it as emphasized. $values = array('%color' => 'blue'); print t('My favorite color is %color.', $values); Not only will this remove any dangerous characters from the value, but it will also insert markup to treat that text as emphasized text. By default, the preceding code would result in the printing of the string My favorite color is blue. The emphasis tags were added by a theme function (theme_placeholder()) called by the t() function. There are more things that can be done with t(), format_plural(), translation contexts, and other translation system features. To learn more, you may want to start with the API documentation for t() at http://api.drupal.org/api/ function/t/7. We have taken a sizable detour to talk about the translation system, but with good reason. It is a tremendously powerful feature of Drupal, and should be used in all of your code. Not only does it make modules translatable, but it adds a layer of security. It can even be put to some interesting (if unorthodox) uses, as is exemplified by the String Overrides module at http://drupal.org/project/stringoverrides. At this point, we have created a working module, though the only thing that it does is display help text. It's time to make this module a little more interesting. In the next section we will use the Block API to write code that generates a block listing all of the currently enabled modules. Working with the Block API In the first chapter we talked about blocks, and in your passing usage of Drupal, you have already no doubt encountered block configuration and management. In this section, we are going to learn how to create blocks in code. The Block API provides the tools for hooking custom code into the block subsystem. The Block API has changed substantially since Drupal 6. In Drupal 6, there was only one function used for all block operations. Now there is a family of related functions. We are going to create a block that displays a bulleted list of all of the modules currently enabled on our site. [ 42 ]
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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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Page 15 and 16: Why Subscribe? • Fully searchable
Page 17 and 18: Table of Contents Tools for develop
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Page 21 and 22: Table of Contents Using hook_node_a
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Page 25 and 26: Preface Chapter 5, Building an Admi
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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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