Workshop by Penny Leach at the MoodleMoot Barcelona 2008 on 24 October 2008

1. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Mahara Development for Moodle Developers
Penny Leach <penny@catalyst.net.nz>
MoodleMoot Barcelona
October 24 2008
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

2. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
Where the similarities come from
Mahara’s General approach
2 Key Similarities
DML & XMLDB
Upgrades
Language Packs
config.php
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

3. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
3 Key Differences
Database
Input and Output
Error handling and debugging
Miscellaneous differences
4 Other main components
Signalling
5 Plugin Types
Introduction to Plugins
Artefact Plugins
Other Plugins
Themes
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

4. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
6 Code flow layout
7 A typical Mahara Page
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

5. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
Where the similarities come from
Mahara’s General approach
2 Key Similarities
3 Key Differences
4 Other main components
5 Plugin Types
6 Code flow layout
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

6. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Where the similarities come from
History
• A very rushed first 3 months
• A lot of code taken from Moodle by me
• Over time we diverged and broke compatibility
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

7. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Mahara’s General approach
General approach
• PHP5 from the start
• Much stricter approach
• Much more OO and later PHP features.
• For example, plugin definitions are all abstract classes
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

8. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
2 Key Similarities
DML & XMLDB
Upgrades
Language Packs
config.php
3 Key Differences
4 Other main components
5 Plugin Types
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara6 Code flow layout
Development for Moodle Developers

9. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
DML & XMLDB
DDL & XMLDB
• No UI to generate XML or upgrade PHP
• Learn the API and write it yourself
• Learn the XML and write it yourself
• Offset by removal of NEXT/PREV checking
• Added some changes back into Moodle early on
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

10. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Upgrades
Upgrades
• version.php and database version number
• db/upgrade.php and db/install.xml as usual
• Upgrades require administrative login
• disablelogin & minupgradefrom
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

11. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Language Packs
Language Packs
• get string
• $string array of keys to values
• Use of sprintf and %s rather than eval and $a
• Slightly different get string function contract (variable
arguments rather than one mixed argument)
• Helpfiles are more often automatically detected based on
form element, page and section
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

12. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
config.php
config.php
• Very similar beginning - db details
• docroot is detected
• dataroot the same
• wwwroot optional (detected but not perfect)
• Then divergence begins
• One big difference:
• config.php
• config-dist.php
• config-defaults.php
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

13. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
2 Key Similarities
3 Key Differences
Database
Input and Output
Error handling and debugging
Miscellaneous differences
4 Other main components
5 Plugin Types
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara6 Code flow layout
Development for Moodle Developers

14. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Database
DML
• Same starting point but a few divergences:
• Prepared statements and placeholders (select * from
{table} where field = ?)
• No get records anymore, get records array and
get records assoc instead
• Some function contracts changed to suit $values array
between $sql and other things like $limit
• 138 lines of diff in grep function between Moodle and
Mahara but really it’s not that different
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

15. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Database
More DB differences
• Referential Integrity - there in XMLDB but disabled in
Moodle for now
• Proper date fields rather than integers
• Much more use of transactions
• No magic id field on every table
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

16. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Input and Output
Forms
• Completely different to Moodle, they were developed about
the same time
• Pieforms, written by a Mahara developer, Nigel.
• Maintained as a separate library on sourceforge
• Array based form definitions with callback functions
• Much simpler than QuickForms and easier to customise
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

17. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Input and Output
Parameter Input
• Completely different approach
• Moodle will clean parameters to match rules
• Mahara will reject anything that doesn’t match
• Moodle:
• $id = required param(’id’, PARAM INT);
• $id = optional param(’id’, 0, PARAM INT);
• Mahara:
• $id = param integer(’id’);
• $id = param integer(’id’, 0);
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

18. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Error handling and debugging
Error handling and debugging
• Exceptions from the start
• Throw specifically, catch generally in most cases
• Clearly defined Exception hierarchy, which defines the
handling of errors
• Logging targets (screen/logs), could be more later (eg
email to developers)
• Logging levels: debug, warn, environment
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

19. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Miscellaneous differences
Cron
• Proper scheduler
• Database example
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

20. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Miscellaneous differences
Miscellaneous differences
• less use of globals - get config rather than global $CFG
• Contentious - use of Smarty for templates
• Mochikit rather than YUI
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

21. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
2 Key Similarities
3 Key Differences
4 Other main components
Signalling
5 Plugin Types
6 Code flow layout
7 A typical Mahara Page
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

22. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Signalling
Event handling
• Similar to Moodle
• handle event
• Core throws events, plugins can subscribe
• They register which events they want at install/upgrade
• Processed at cron
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

23. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Signalling
Activity handling
• Like events, but for user activity
• Eg, feedback on a view
• activity occurred
• Notifies all relevant users
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

24. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
2 Key Similarities
3 Key Differences
4 Other main components
5 Plugin Types
Introduction to Plugins
Artefact Plugins
Other Plugins
Themes
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara6 Code flow layout
Development for Moodle Developers

25. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Introduction to Plugins
Introduction to Plugins
• Registers at installation time:
• Cronjobs
• Event subscriptions
• Also exports config form
• Exactly the same way to install and upgrade as Moodle
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

26. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Introduction to Plugins
The Plugin base class
• get cron
• get event subscriptions
• postinst
• has config
• get activity types
• Subtypes can enforce their own abstract methods
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

27. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Artefact Plugins
Artefact
• Richest plugin type
• Two new classes
• PluginArtefact
• get artefact types
• get block types
• get plugin name
• menu items
• group tabs
• ArtefactType
• get icon
• is singular
• public feedback allowed
• has config
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

28. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Artefact Plugins
More on Artefacts
• Generally plugins will write a new ArtefactType base class
• Example: artefact plugin Foo will make PluginArtefactFoo
and ArtefactTypeFoo
• For each artefact type that get artefact types returns,
ArtefactTypeFoo subclass
• Should be fairly obvious that the API is quite flexible
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

29. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Other Plugins
Blocktype
• Blocktypes define how artefacts are displayed in a view
• Probably the most simple Mahara plugin
• We’ll have a go at writing one this afternoon
• Bound to either an artefact plugin or ’system’ level
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

30. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Other Plugins
Blocktype classes
• New subclass: PluginBlocktype extends Plugin
• single only
• get title
• get description
• get categories
• get viewtypes
• render instance
• artefactchooser element
• ... more
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

31. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Other Plugins
Notification
• PluginNotification extends Plugin
• one new method: notify user
• Current: internal messages, email, emaildigest
• Could be: jabber plugin, for example
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

32. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Other Plugins
Interaction
• Used for adding things like Forums to Groups
• Two new subclass:
• PluginInteraction extends Plugin
• instance config form
• instance config save
• InteractionInstance
• get plugin
• interaction remove user
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

33. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Other Plugins
Other plugins
• Authentication - internal, ldap, xmlrpc (MNET), imap
• Search - internal (sql), solr
• Grouptype - standard, course
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

34. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Themes
Themes
• theme directory contains:
• config.php - parent theme, theme name
• static - stylesheets, images
• templates - smarty templates
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

35. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
2 Key Similarities
3 Key Differences
4 Other main components
5 Plugin Types
6 Code flow layout
7 A typical Mahara Page
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

36. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Layout
• Switch to code
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

37. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
2 Key Similarities
3 Key Differences
4 Other main components
5 Plugin Types
6 Code flow layout
7 A typical Mahara Page
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

38. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
A typical Mahara Page
• Switch to code
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

39. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
1 Introduction
2 Key Similarities
3 Key Differences
4 Other main components
5 Plugin Types
6 Code flow layout
7 A typical Mahara Page
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers

40. Introduction Key Similarities Key Differences Other main components Plugin Types Code flow layout A typical Mahara Page
Ideas?
Ideas?
• Themes
• Blocktypes
• Twitter
• Last.fm
• Dopplr
• Facebook
• Flickr
Penny Leach <penny@catalyst.net.nz> MoodleMoot Barcelona
Mahara Development for Moodle Developers