A brief overview of Drupal 7

1. A brief overview of Drupal 7 By Robin Isard, Systems Librarian Algoma University

2. What I'm going to look at • Overview of Drupal 7 • The module system • How Drupal manages your data • Case study – 2 years working with Drupal

3. What is drupal? • Content Management System • Becoming more of a Content Management Framework • Created by Dries Buytaert, a Belgian computer science student in 1998 • 3 major releases since then • Current major release is Drupal 7 • As of 2011 approximately 630,000 subscribed users • “A drop”

4. Architectural Overview • Essentially a LAMP stack • Modular • Core • Contributed • Custom • Themes • Business logic intensive

5. Hierarchical ordering of content Tracking system Statistics OpenID login Logging Theming system Update manager Trigger system Core • Core modules • Blogs • Comments • Aggregator (RDF, RSS, Atom feeds) • Forums • Polls • Taxonomy (tagging) • Menu customization

6. Drupal community

7. Contributed modules • Functionality and themes • 9947 modules total • 3929 compatible with Drupal 7 • “Content”: 551 • “File Management”: 90 • “Administration”: 343 • “Themes”: 298

8. IMCE

9. How modules work • A collection of php files designed to implement some find of functionality • /sites/default/modules • mymod.info • mymod.install • mymod.module

10. .info • name = Administration menu • description = "Provides a dropdown menu to most administrative tasks and other common destinations (to users with the proper permissions)." • package = Administration • ; Purposively added for feature development. • version = 7.x-3.x-dev • core = 7.x • project = admin_menu

11. .install • /** • * @file • * Install, update, and uninstall functions for the admin menu module. • */ • /** • * Implements hook_schema(). • */ • function admin_menu_schema() { • $schema['cache_admin_menu'] = drupal_get_schema_unprocessed('system', 'cache'); • $schema['cache_admin_menu']['description'] = 'Cache table for Administration menu to store client-side caching hashes.'; • return $schema; • }

12. .module • Hook system • Php function • Defined input and output • Allows you to implement a certain behavior at a certain point in drupal core

13. Hooks • <moudle_name>_<hook_name>() • hook_user_load() • mymod_user_load() • 342 available hooks • hook_comment_load • hook_cron • hook_css_alter • hook_field_validate

14. Example • /** • * Implements hook_help(). • */ • function admin_menu_help($path, $arg) { • switch ($path) { • case 'admin/settings/admin_menu': • return t('The administration menu module provides a dropdown • menu arranged for one- or two-click access to most administrative • Tasks … the menu.'); • case 'admin/help#admin_menu': • $output = ''; • $output .= '<p>' . t('The administration menu module provides a dropdown menu arranged for one- or two-click ....');

15. APIs • Module system (Drupal hooks) • Database abstraction layer (Schema API) • Menu system • Form generation • File upload system • Field API • Search system • Node access system • Theme system

16. Data access and storage

17. Data management • By default a LAMP stack • Other database options available with more or less support • Drupal 7 has a rewritten database abstraction layer • PostgreSQL now a first class member of the community • MongoDB • Essentially uses Object-relational mapping

18. APIs • Entity (core) • Entity API • Schema API

19. Important data management concepts • Entities • Users • Taxonomy terms • Comments • Nodes • Fields • Entity + Fields = Bundles

20. Bundle - Example • news_item (a node entity) + • Date (field) • Subject (field) = • “news_item bundle”

21. Key entity hooks • hook_entity_info() • Entity (core) • hook_schema() • Schema API • Entity API • entity_create() • entity_save() • entity_delete() • entity_view() • entity_access().

22. hook_entity_info() • function user_entity_info() { • $return = array( • 'user' => array( • 'label' => t('User'), • 'controller class' => 'UserController', • 'base table' => 'users', • 'uri callback' => 'user_uri', • 'label callback' => 'format_username', • 'fieldable' => TRUE, • 'entity keys' => array( • 'id' => 'uid', • ), • '

23. hook_schema() • function user_schema() { • $schema['authmap'] = array( • 'description' => 'Stores distributed authentication mapping.', • 'fields' => array( • 'aid' => array( • 'description' => 'Primary Key: Unique authmap ID.', • 'type' => 'serial', • 'unsigned' => TRUE, • 'not null' => TRUE, • ), • 'uid' => array( • 'type' => 'int', • 'not null' => TRUE, • 'default' => 0, • 'description' => "User's {users}.uid.",

24. hook_schema() • Supports primary and foreign keys • Supports indexes • Field lengths • Precision • Signed / unsigned

25. Data storage example

26. Data storage example • public | node | table | • public | field_data_field_db_access_link | table | • public | field_data_field_db_build_name | table | • public | field_data_field_db_description | table | • public | field_data_field_db_ezp_note | table | • public | field_data_field_db_ezp_test | table | • public | field_data_field_db_sfx_name | table | • public | field_data_field_db_url | table |

27. TABLE: field_data_field_db_url entity_type | node bundle | db deleted | 0 entity_id | 164 revision_id | 164 language | und delta | 0 field_db_url_value | http://.... field_db_url_format | Data storage example • TABLE: node • nid | 164 • vid | 164 • type | db • language | und • title | Women Writers' Project • uid | 1 • status | 1 • created | 1317243764 • changed | 1332779771 • comment | 1 • promote | 0 • sticky | 0 • tnid | 0 • translate | 0

28. Viewing your data • Views module • Still a contributed module • Essentially a report writer • Complicated • Database API

29. An example: Algoma University's Archive

30. Algoma University Archive • Over 25,000 images and documents • 3 TB of data on scattered hard drives • Most of the data important for legal purposes • Index housed in InMagic-DBtextworks • “Relational like” • ASP driven • No social media aspects • No means to display the content in an engaging way

31. Questions we asked about a new CMS • Service integration • Is there documentation? • Is there an API? Does it support data exchange protocols? • JSON • XML • RDP

32. Questions we asked about a new CMS • Data access and storage • How does it store data? • Does it have a CRUD layer? • Can I get my data out of it in standard formats? • CSV • XML • What options are there for non-sql data?

33. Migration • 2010 project started to update the archive • We chose Drupal because • It seemed to answer the questions listed above • of it's very large user community • recommendations from peers • it's ability to integrate with enterprise technologies like Fedora Commons and Solr • It's social media abilities

34. Phase 1 • Get the data out of InMagic and into Drupal • Took nearly 4 months • Process • Dump the data out of InMagic as CSV files • Import into PostgreSQL • Use SQL to clean up and format the data • Use “migration module” to import the cleaned up tables into Drupal

35. Phase 2 • Use Drupal's extensibility to ability to meet archivist needs for the archive • Problems with contirb • Postgres • Bad code • Malfunctioning modules • Dates • Unix time stamp no good for archives

36. Phase 3 – in planning • Migrate to drupal 7 • Needs to be done • No back-porting • Drupal is now smarter about databases – which is a problem

37. Lessons learned - modules • Drupal runs the show • Always interact with Drupal via a module • Stay as close to core as possible • Is this the best possible module for the job? • Put time into choosing modules • When was the last commit? • Do you understand the code yourself? • Is there a plan to upgrade it? • Read the code for you modules • You should be able to fix it yourself

38. Lessons learned - database • Drupal doesn't really like relational databases • Do you know what a given module will do to the DB? • Categories module • Does it use MySQL specific statements? • Use Fields and Views as much as possible • Always interact with the DB via a module

39. The possibilities • Database layer can be rewritten • All kinds of data stores theoretically possible • Can be conceptualized as simply a user interface for different kinds of data stores • Discovery • Solr integration • Islandora • Web services