My  first  Drupal  module!  Why  not?  

About @Cvetko •  Started as PHP developer with

custom CMS •  “You need Linux” they said •  I know Drupal since version 4.x

•  Working as Sys admin, Drupal developer, iOS developer, etc.

Twitter @Cvetko Skype damjan.cvetan Email damjan@agiledrop.com

Drupal

•  Available from drupal.org. •  Runs on every machine with

PHP, supported database and web server.

•  Very customizable (themes, modules).

•  Good documented. •  No limits.

A whole bunch of modules

Which one to use?

Missing a module?

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

Where to?

Drupal  

Core  Modules  

Contributed  Modules  

Custom  Module  

Core  Themes  

Contributed  Themes  

Custom  Theme  

/sites/[all|mysite.com]/custom  

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

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.

*.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, …

Checkpoint

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

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!

Half way there

Hook(s)

hook – [hoo k], noun � a curved or angular piece of metal or other hard substance for catching, pulling, holding, or suspending something.

•  Fundamental to Drupal modules. •  A way to interact with the core code. •  Occur at various points in execution thread. •  An event listener. •  Names as foo_bar() –  foo : module name, bar : hook name

How does it work?

Call  for  hook:  hook_menu()  

Drupal  runFme   Drupal  runFme  

Call  dispatch  

Foreach (enabled_module): ! module_name_menu(); !end foreach; !

locale_menu() !user_menu() !contact_menu() !help_menu() !… !… !dc_stats_menu() !… !… !trigger_menu() !path_menu() !

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/

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

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.

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.)

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  }  

   

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!

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.

Books

•  Drupal 7 Development by Example

•  Beginning Drupal 7

•  Drupal 7 Module Development

•  …

•  …

Q  &  A