Drupal Module development and Supports

1. My first Drupal module!
Why not?

2. About @ Gajendra Sharma
• Started as PHP developer with
custom CMS
•“You need Linux” they said
•I know Drupal since version 5.x
Email: gajen.ksharma@gmail
Skype: gajendrakumarsharma1688
LinkedIn: www.linkedin.com/in/gajendrasharma

3. Drupal
• Available from drupal.org.
• Runs on every machine with
PHP, supported database
and web server.
• Very customizable
(themes, modules).
• Good documented.
• No limits.

4. A whole bunch of modules

5. Which one to use?

6. Missing a module?

7. Three kinds of modules (3 Cs)
• Core
– Shipped with Drupal
– Approved by core developers and community
• Contributed
– Written by community
– Shared under the same GNU Public License
• Custom
– Created by website developer

8. Where to?
Drupal
Core Modules Core Themes
Contributed
Modules
Contributed Themes
Custom Module
Custom Theme
/sites/[all|mysite.com]/custom

9. Module name
• Should be a UNIQUE “short name”
• Used in all file and function names
• Must start with a letter
• Only lower-case letters and underscores
• We will use name: “dc_stat”
– For display current node/user stats

10. Create a folder + module file
• Module name “dc_stats”.
• Create empty folder:
– /sites/*/modules/custom/dc_stats/
• Create new file “dc_stats.module” with
opening PHP tag and NO closing tag!!
• Create new file “dc_stats.info” for
meta information.

11. *.info
• Required for every module!
• Standard .ini file format – key/value pairs
name = Drupal statistic!
description = Provides some statistic data.!
core = 7.x!
package = Damjan Cvetan!
Other optional keys:
stylesheets, scripts, files, dependencies, …

12. Checkpoint
• Navigate to Modules section on your site
• You should see your module
• Enable it!

13. Coding standards
• Use an indent of 2 spaces, no tabs!
•
•
•
•
UNIX line ending (n)
Omit closing “?>” PHP tag
Constants should be all-uppercase
Comments are your friends!

14. Half way there
Hook(s)
hook – [hoo k], noun Ÿ a
curved or angular piece of
metal or other hard
substance for catching,
pulling, holding, or
suspending something.
• Fundamental to Drupal

15. How does it work?
Call dispatch
Foreach (enabled_module):!
module_name_menu();!
end foreach;!
Call for hook:
hook_menu()
Drupal runFme
locale_menu()!
user_menu()!
contact_menu()!
help_menu()!
…!
…!
dc_stats_menu()!
…!
…!
trigger_menu()!
path_menu()!
Drupal runFme

16. Hooks line up!
• hook_help() – Provides
available documentation.
• hook_menu() – For paths registration
in order to define how URL request
are handled.
• hook_init() – Run at the beginning of
page request.
• hook_cron() – Called whenever a cron
run happens.
• More at http://api.drupal.org/

17. API.drupal.org
• Drupal developer’s documentation.
• Doc for Drupal 4.6+.
• Describes function calls, their
parameters and return values.
• You can see the code and “who” is
calling this code within Drupal.
• http://api.drupal.org

18. Let’s code
• Define callback function dc_stats_page()
as follows:
funcFon dc_stats_page(){
return "Hello world! You’re awesome!”;
}
• This will return defined string on call.
• Put this code in dc_stats.module file.

19. Hey Drupal! Come in!
• Register path with hook_menu().
• We will use basic return array structure.
funcFon dc_stats_menu(){
$items['dc/stats-page'] = array(
'Ftle' => 'Stats info page',
'page callback' => 'dc_stats_page',
'access arguments' => array('access content'),
'type' => MENU_CALLBACK,
);
return $items;
}
Visit URL: /dc/stats-page to see if it works.
(You might need to clear cache first.)

20. Get some real data
funcFon dc_stats_page(){
drupal_set_Ftle("Drupal staFsFcs");
$node_count = $db_node_count;
$user_count = $db_users_count;
$header = array("InformaFon", "Value");
$rows[] = array('Number of nodes:', $node_count);
$rows[] = array('Number of users:', $user_count);
return theme_table(array( 'header' => $header,
'rows' => $rows,
…
…
)); // return
}

21. Happy ending
• Refresh your page and see your work.
• You can do much more – I’m certain!
• Use your PHP + any other knowledge
with existing Drupal functions, hooks
and variables!

22. Links to consider
• http://api.drupal.org
http://drupalcontrib.org/
• http://buildamodule.com/
• http://drupal.org/project/devel
– A suit of modules containing fun for
module developers and themers.

23. Books
• Drupal 7 Development by Example
• Beginning Drupal 7
• Drupal 7 Module Development
• …
• …

24. Q&A