1. Hook, Drush, and Alters Oh Mai! btopro @btopro http://btopro.com/ http://drupal.psu.edu/blog/1 Bryan Ollendyke

2. Topics This is a code deep dive “Hello World” dev @ 10am in 206 Modules and Dev must haves Cover basic hooks Cover more obscure but useful hooks Examples provided throughout via contrib

3. Places to look for help Stackoverflow Api.drupal.org Drupal.org issue queues Drush.org http://dropbucket.org/

4. Must Have projects devel (drush support) Easy to debug all aspects of drupal objects drush - Drupal via Command line Ex: drush @sites cc all Clear cache on all sites in this multi-site coder (drush support) Feedback on code quality based on Drupal community conventions Provides security audits and suggestions libraries API for reusable, non-drupal lib integration

5. Nice to Have projects devel_themer Theme debugging / template sniffing query_coder Convert SQL to Drupal query language features (drush support) Bundle exportable configuration Maintain consistency / version control IA profiler_builder (drush support) Help converting a site into a distribution Consistency across build routines (ulmus)

6. Nice to Have projects registry_rebuild (drush) Drush extension, life saver at times backup_migrate (drush support) UI / Drush based migrations module_builder (drush support) Generate module skeletons quickly examples Community approved example implementations of APIs

7. Other good API projects entity field_collection replicate Libraries context rules

8. Hook/alter architecture Commonly referred to as “the drupal way” Easy to override some else’s code Goal is to never modify others code unless absolutely necessary Common to write a “sitename_helper” style module loaded with alters

9. A few random Hooks init page_build page_alter form_alter menu menu_alter admin_paths theme_registry_alter custom_theme views_query_alter

10. Hook Example page_build page_alter

11. Alter Example page_build page_alter

12. Useful API functions arg($id) – part of the url (node/67/edit) arg(0) == ‘node’ arg(1) == 67 arg(2) == ‘edit’ arg(3) NULL menu_get_item – pull object from URL $node = menu_get_item(); the same as node_load(arg(1)); but more flexible (works with other menu objects)

13. Useful API functions module_load_include(‘module’, ‘yourproject’) Load an include file w.o. knowing path module_invokes(‘cron’); List all modules invoking a hook drupal_static($value, ‘default’); Centralized static caching drupal_form_submit(‘name’, $values) Programmatically trigger form to submit dvm($node) or dpm($node) Required devel, clean var_dump of object

14. Build own hooks module_invoke_all (‘things_stuff’) Assemble an array of all returns {MODULENAME}_things_stuff drupal_alter(‘things_stuff’, $data) $data passed by reference to all modules {MODULE}_things_stuff_alter(&$data); Invoking existing hook (like page_build) Call your module_invoke_all(‘myhook’); Follow it by drupal_alter(‘myhook’, $data); This allows other devs to safely mod

15. Common Site Example mooc_helper Supplamental glue code for install profile Mostly just injects minor changes Drupal.org/project/mooc Then view repository

16. Simple Library Example quojs Helps include quojs with Drupal Allows you to invoke js library from other modules Requires libraries API module drupal.org/project/quojs

17. Complex Example regions Stand alone “block” areas across-theme Creates its own API that is invoked Add “widgets” that function across themes Reuse components across sites easier Export via features cleaner w.o. theme issues drupal.org/project/regions

18. Complex Example cis_connector Web service endpoint for my edtech distros Caches http calls through a wrapper Uses mix of drupal_static and cache_set drupal.org/project/cis_connector https://drupal.psu.edu/node/779

19. Complex Example entity_iframe Stand alone functionality for any site Themeable via tpl.php files Views integration Dynamic url rewriting per request Allows secure cross-frame communication drupal.org/project/entity_iframe

20. Simple Drush example drush dl outline_designer views regions cis_connector Download outline_designer, views, regions, and cis_connector to sites/all/modules --y can be used to answer yes to everything drush @sites cc all Clear the cache on all sites

21. Writing your own Drush book_copy Replicate book outlines in Drupal Drush support for passing a node id drupal.org/project/book_copy

22. Maximize reuse See if functionality could be useful elsewhere Solve for Drupal, not for PSU hooks/alters to solution, PSU being just 1 Code “The drupal way” Try to structure code as follows: Contrib module – given away PSU – specific to university College – specific to our usage Implementation – specific to 1 deployment

23. Questions? #dcpsu @psu_drupal