Hook, Drush, and Alters Oh Mai!Hook, Drush, and Alters Oh Mai!

btopro@btopro

http://btopro.com/http://drupal.psu.edu/blog/1

Bryan Ollendyke

TopicsTopics

• 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

Places to look for helpPlaces to look for help

• Stackoverflow• Api.drupal.org• Drupal.org issue queues• Drush.org• http://dropbucket.org/

Must Have projectsMust 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

Nice to Have projectsNice 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)

Nice to Have projectsNice 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

Other good API projectsOther good API projects

• entity• field_collection• replicate• Libraries• context• rules

Hook/alter architectureHook/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

A few random HooksA few random Hooks

• init• page_build• page_alter• form_alter• menu• menu_alter• admin_paths• theme_registry_alter• custom_theme• views_query_alter

Hook ExampleHook Example

• page_build• page_alter

Alter ExampleAlter Example

• page_build• page_alter

Useful API functionsUseful 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)

Useful API functionsUseful 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

Build own hooksBuild 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

Common Site ExampleCommon Site Example

• mooc_helper• Supplamental glue code for install profile• Mostly just injects minor changes• Drupal.org/project/mooc

• Then view repository

Simple Library ExampleSimple 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

Complex ExampleComplex 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

Complex ExampleComplex 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

Complex ExampleComplex 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

Simple Drush exampleSimple 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

Writing your own DrushWriting your own Drush

• book_copy• Replicate book outlines in Drupal• Drush support for passing a node id• drupal.org/project/book_copy

Maximize reuseMaximize 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

Questions?Questions?

#dcpsu#dcpsu@psu_drupal@psu_drupal