Talk given at Drupalcamp Bucharest 2011.

1. LEARNING THE BASICS
OF THE DRUPAL API
Badiu Alexandru
Drupalcamp Bucharest 2011

2. THIS
• We’re going to use Drupal 7
• For beginners, intended as a
continuation of “From zero to hero”
• Going to assume you know basic
concepts such as blocks and nodes
Drupalcamp Bucharest 2011

3. YOU’LL
• The basics of module development
• How to create blocks
• How to check for permissions
• How to create forms
• How to create menu items
• How to send email
Drupalcamp Bucharest 2011

4. MODULES
• Modules are the building blocks
• name.info
• name.module
• sites/all/modules
Drupalcamp Bucharest 2011

5. MODULES
• Create blocks
• Create content types
• Create pages and forms
• Augment Drupal core
• Augment Drupal modules
Drupalcamp Bucharest 2011

6. DCAMP.M
• DrupalCamp Forward
• Allows a user to forward a node url
to a friend
• Displays a block on each node page
• Can appear only on specific node
types
Drupalcamp Bucharest 2011

7. DCAMP.M
• dcamp.info
name = DrupalCamp Forward
description = Drupalcamp D7 Demo
package = Drupalcamp
version = 1.0
core = 7.x
files[] = dcamp.module
Drupalcamp Bucharest 2011

8. DCAMP.M
• dcamp.module
• Is a php file
• Contains the module code
• Implements hooks
Drupalcamp Bucharest 2011

9. HOOKS
• Hooks are callbacks
• Everytime an action is performed in
Drupal a specific hook is called
• You can alter the action data
• You can do unrelated things
Drupalcamp Bucharest 2011

10. HOOKS
• hook_name
• function dcamp_name($arg1, $arg2)
{...}
Drupalcamp Bucharest 2011

11. HOOKS
• http://api.drupal.org/api/drupal/
includes--module.inc/group/hooks/
7
• Lots of them
• Block, Node, Forms, Images, Menus,
Taxonomy, Permissions, Users
Drupalcamp Bucharest 2011

12. BLOCK
• hook_block_info
• hook_block_view
• function dcamp_block_info()
• function dcamp_block_view($delta =
‘’)
Drupalcamp Bucharest 2011

13. BLOCK
function dcamp_block_info() {
$blocks = array(
'forward_block' => array(
'info' => t('Forward node block'),
'cache' => DRUPAL_CACHE_PER_ROLE
)
);
return $blocks;
}
function dcamp_block_view($delta = '') {
$block = array(
'subject' => t('Spread the word'),
'content' => 'Block contents.'
);
return $block;
}
Drupalcamp Bucharest 2011

14. BLOCK
• The block appears on every page
• We want to limit it to roles via
permissions
• We want to limit it to nodes
Drupalcamp Bucharest 2011

15. PERMISSIO
• hook_permission
• Returns an array of permissions
• user_access($perm) checks
function dcamp_permission() {
return array(
'forward node' => array(
'title' => t('Forward nodes to friends')
),
);
}
Drupalcamp Bucharest 2011

16. PERMISSIO
function dcamp_block_content() {
if (!user_access('forward node')) {
return '';
}
return "Block content.";
}
Drupalcamp Bucharest 2011

17. LIMITING
• Internal Drupal path: node/4
• Path alias: page/about-us.html
• arg(0) = node, arg(1) = 4
if (arg(0) == 'node' && is_numeric(arg(1))) {
$nid = arg(1);
}
else {
return '';
}
Drupalcamp Bucharest 2011

18. FORMS
• Forms are generated via a structured
array of elements
• They have an ID which is the
function that returns the structure
• drupal_get_form(‘dcamp_form’)
returns the form HTML
Drupalcamp Bucharest 2011

19. FORMS
• Form generation: dcamp_form
• Form validation:
dcamp_form_validate
• Form submit: dcamp_form_submit
Drupalcamp Bucharest 2011

20. FORM
function dcamp_form($form, $form_state, $nid) {
$form = array();
$form['nid'] = array(
'#type' => 'hidden',
'#value' => $nid,
);
$form['email'] = array(
'#type' => 'textfield',
'#title' => t('Email address'),
'#size' => 25,
'#required' => TRUE
);
$form['submit'] = array(
'#type' => 'submit',
'#value' => t('Forward')
);
return $form;
}
Drupalcamp Bucharest 2011

21. FORM
• $form_state[‘values’]
• form_set_error
function dcamp_form_validate($form, &$form_state) {
$email = $form_state['values']['email'];
if (!valid_email_address($email)) {
form_set_error('email', t('Please enter a valid email
address.'));
}
}
Drupalcamp Bucharest 2011

22. FORM
function dcamp_form_submit($form, &$form_state) {
global $user;
$email = $form_state['values']['email'];
$nid = $form_state['values']['nid'];
// send an email with the url to the email address
drupal_set_message(t('The node has been forwarded to
%email.', array('%email' => $email)));
}
Drupalcamp Bucharest 2011

23. SENDING
• Complicated
• Requires implementing a hook -
hook_mail
• Different email types
• Of course, you can just use mail()
Drupalcamp Bucharest 2011

24. SENDING
function dcamp_mail($key, &$message, $params) {
if ($key == 'forward') {
$langcode = $message['language']->language;
$message['subject'] = t('Recommended site', array(),
array('langcode' => $langcode));
$message['body'][] = t("You've been recommended this !
url.", array('!url' => url('node/' . $params['nid'],
array('absolute' => TRUE))), array('langcode' => $langcode));
}
}
drupal_mail('dcamp', 'forward', $email,
user_preferred_language($user), array('nid' => $nid));
Drupalcamp Bucharest 2011

25. ADMIN
• We want an admin page
• admin/config/content/forward
• Another hook (no surprise there)
• hook_menu
• We’ll use a form
Drupalcamp Bucharest 2011

26. MENU
• Every page in a Drupal site is a menu
item
• Does not mean it has to appear in
the site menu
Drupalcamp Bucharest 2011

27. MENU
• Url:
• admin/config/content/forward
• wildcards: node/%/forward
• Title
• Description
• Type: Normal, Tab, Callback
Drupalcamp Bucharest 2011

28. MENU
• Page callback
• Page arguments
• Access callback
• Access arguments
Drupalcamp Bucharest 2011

29. SAVING
• You could use the database
• variable_set(‘variable’, $value);
• Works with arrays and objects too
• variable_get(‘variable’,
$default_value);
Drupalcamp Bucharest 2011

30. RESOURCE
• Read other people’s code
• http://api.drupal.org
• Pro Drupal 7 Development
• Examples - http://
drupalexamples.info/
• Textmate Bundle and alternatives
Drupalcamp Bucharest 2011

31. THANK
andu@ctrlz.ro
http://ctrlz.ro
Drupalcamp Bucharest 2011