Introduction to Module Development

Yi Zhang &Nikki Massaro Kauffman

Modules• Use PHP to

customize Drupal.

• Can access variables used in Drupal Core.

• Can override/enhance core functions through “hooks”.

Use them wisely…

…or you may have conflicts.

Why Module Development?

Content Types

Views Themes Modules

GUI GUI Code Code

Data Presentation Presentation Data

Where Modules Live

sites/all/

modules/contrib/custom/

themes/

Where Modules Live

sites/all/

modules/contrib/custom/

themes/

Where Modules Live

sites/all/

modules/contrib/custom/

themes/

3rd party modules

Where Modules Live

sites/all/

modules/contrib/custom/

themes/DIY modules

Recipe for a Module

Ingredients

.info

.module

optional files

optional folders

Recipe for a Module

Ingredients

.info – module info, files, and

dependencies

.module

optional files

optional folders

Recipe for a Module

Ingredients

.info – module info, files, and

dependencies

.module – function of the module

optional files

optional folders

Recipe for a Module

Ingredients

.info – module info, files, and

dependencies

.module – function of the module

optional files – .install, .inc, .tpl.php,

etc.

optional folders

Recipe for a Module

Ingredients

.info – module info, files, and

dependencies

.module – function of the module

optional files – .inc, .tpl.php, etc.

optional folders – css, images, etc.

Drupal Hooks

• PHP function• Modifies Drupal

behavior• Similar to callback–Like triggered events

• Hook similar to object-oriented–Strict naming

convention

Some Drupal Hooks

• hook_menu• hook_block• hook_footer• hook_schema• hook_help• hook_permission• hook_form

Hook Information: http://api.drupal.org

Hello World!

Test1.info

Test1.module

hook_menu()function test1_menu() { $items = array(); $items['test1'] = array( 'title' => 'PSU Creamery ice cream', 'description' => ’Select your favorite ice cream’, ‘page callback’ => ‘test1_page’, ‘access callback’ => TRUE, ‘type’ => MENU_CALLBACK, );

return $items;}

Test1.module (continue)

Test2.module

hook_help()

function test2_help($path, $arg) { switch ($path) { case 'admin/help#test2':{ $ret_val = '<h3>' . t('About') . '</h3>'; $ret_val = '<p>' . t('This module will show detailed information of a specific ice cream.') . '</p>'; return $ret_val; break; } }}

hook_permission

function test2_permission() { return array( 'administer test2' => array( 'title' => t('Administer test2'), 'description' => t('Perform administrative tasks on test2 functionality'), ), );}

Configuration

Test3.info

PSU Drupal Camp 2013

Test3.module // Admin configuration group. $items['admin/config/drupalcamp'] = array( 'title' => 'drupalcamp', 'description' => 'Administer drupalcamp', 'access arguments' => array('administer drupalcamp'), ); // Admin configuration - Settings. $items['admin/config/drupalcamp/test3/manage'] = array( 'title' => 'test3', 'description' => 'Manage test3 settings and configurations.', 'access arguments' => array('administer test3'), 'page callback' => 'drupal_get_form', 'page arguments’=> array('test3_admin_settings_form'), );

hook_form()function test3_admin_settings_form($node, &$form_state) { $form = array(); $form['overview'] = array( '#markup' => t('This interface allows administrators to manage general test3 Settings'), '#prefix' => '<p>', '#suffix' => '</p>’,); $form['test3_maxnum'] = array( '#title' => t('Max number of cones per customer'), '#type' => 'textfield', '#default_value' => '2', '#required' => TRUE,); $form['submit'] = array( '#type' => 'submit', '#value' => t('Save'),); return $form;}

Validation

PSU Drupal Camp 2013

Test4.module

hook_validate()function test4_admin_settings_form_validate($form, &$form_state) {// Regular expression for validating input number. $maxnum_regex = '/^[+-]?\d+$/';

// Shorthand for long array names. $input_num = $form_state['values']['maxnum'];

// Validate maxnum format. if (!preg_match($maxnum_regex, $input_num)) { form_set_error('maxnum', t('Invalid number. Must be an integer.')); }

// Validate maxnum value. if ($input_num <= 0) { form_set_error('maxnum', t('Must input a positive number.')); }}

validated test4 setting submission

function test4_admin_settings_form_submit($form, &$form_state) { // Rebuild the form. $form_state['rebuild'] = TRUE;

// Save test4 setting variables. variable_set('maxnum', $form_state['values']['maxnum']);

// Notify user. drupal_set_message(t('test4 settings saved.'), 'status');}

PSU Drupal Camp 2013

Enable the Module

.install file

• runs when a module is enabled for the first time

• creates database tables and fields. • instructions are included in a

_install() function.

Test5.install

PSU Drupal Camp 2013

hook_install()function test5_install() { // Set default variables. variable_set('maxnum', 2);

// Get localization function for installation as t() may be unavailable. $t = get_t();

// Give user feedback. drupal_set_message($t('test5 variables created.'));}

hook_uninstall()

function test5_uninstall() { // Delete variables. variable_del('maxnum');

$t = get_t();

drupal_set_message($t('test5 variables removed.'));}

PSU Drupal Camp 2013

Test5.module

Remove the validated submission

variable_get('maxnum'),

Return System_settings_form($form);

Thank you!