This document provides an overview of creating a custom module in Drupal. It discusses starting with creating the necessary folder and files for a module called "dc_stats", then provides information on Drupal coding standards and important hooks like hook_menu() and hook_help(). It walks through registering a path with hook_menu() and creating a callback function to output some basic node and user statistics. The document encourages exploring additional Drupal resources and links for continuing to build out custom modules.

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