Local plugins

Disclaimer

Some of these entries are things that Penny has patches for and has not yet committed, and are under discussion. The meta bug for all these items is here: http://tracker.moodle.org/browse/MDL-17376

General customisations

Moodle has been designed with extensibility in mind. There are many plug-in points available throughout Moodle to allow developers add new functionality to Moodle without modifying core code.

See the make a new plugin section of the Developer documentation page for the different plugin types available, and documentation on how to develop for them.

local/ folder for 'hacky' customisations

Sometimes it is not possible to use the available plug-in points to make your change. In situations like this then the local folder is for you. The idea is that instead of scattering your changes throughout the code base, you put them all in a folder called 'local'. Using this folder means you won't have to deal with merging problems when you upgrade the rest of your Moodle installation.

The local folder has some of the plug-in points available which are available to other modules. Perhaps most useful the local/db/ folder can be used to make database schema changes and custom role permissions.

However, using the local folder should be absolutely the last resort. Long term, you will almost certainly find it easier to maintain your changes if you can package them up as one of the standard types of plugins.

Local database changes and version

If you need to make local database customisations that are not easily encapsulated by a block or module, Moodle does support the use of a local db upgrade script, and local version number.

This is almost exactly the same as every other db/upgrade.php and version.php except for the following points:

local/version.php

local/version.php must look like:

$local_version = 2008121700;

local/db/install.xml

Local/ has no install.xml - only an upgrade.php. This is because often the changes that you want to make are not full tables, but just extra columns, and a local install.xml makes less sense than just upgrade.php.

If you would like to create tables using using an install.xml this can be achieved by putting something like that this in your upgrade.php file:

$result = install_from_xmldb_file(dirname(__FILE__).'/install.xml');

local/db/upgrade.php

local/db/upgrade.php must look like:

function xmldb_local_upgrade($oldversion) {

   global $CFG, $db;

   $result = true;

   if ($result && $result < 2008121700) {
       $result = $result && create_table($table);
   }
   return $result;

}

Local post-installation data insertion

In discussion - see http://tracker.moodle.org/browse/MDL-17440

Local capabilities

Just like core and modules, Moodle supports the use of a db/access.php inside local/ to define local capabilities.

The formatting is exactly the same as the other db/access.php scripts - an array keyed by capability name, containing arrays of capability data, like so:

$local_capabilities = array(

   'moodle/local:capability' => array(
       'captype'      => 'write',
       'contextlevel' => CONTEXT_SYSTEM,
       'riskbitmask'  => RISK_SPAM,
   ),

Note that for all local capabilities you add, you'll need to add language strings. Moodle will expect to find them in local/lang/en_utf8/local.php (eg for English) with a key (following the above example) of local:capability

Local event subscriptions

Pending commit

It is often very helpful to be able to write custom code that subscribes to normal events that Moodle throws. It's also handy to be able to throw and catch your own custom events, as the Event API provides a very handy mechanism to do signal handling.

Local event handlers get registered at install/upgrade time just as the event handlers for modules do. To trigger an update when you add a new event handler, you must bump the local version number.

Event handlers must be defined in an array, keyed by event name, with each entry in the array information about the handler, like so:

   $handlers = array(
       'some_core_event'     => array(            // eg 'user_created'
           'handlerfile'     => '/local/lib.php', // example
           'handlerfunction' => 'local_user_create_handler',
           'schedule'        => 'cron'
       )
   );

Local admin menu items and settings

You can add extra configuration items to Moodle by creating a file, local/settings.php which accesses the $ADMIN variable directly and adds new items to it. This will make them appear in the site administration block on the homepage, and create the config options that administrators can change. You can also add whole new custom config pages (admin_externalpage). For example:

$ADMIN->add('root', new admin_category($name, $title); $ADMIN->add('foo', new admin_externalpage($name, $title, $url, $cap);

Local backup and restore hooks

In discussion - see http://tracker.moodle.org/browse/MDL-17444

Local course deletion hook

This is due to be removed, and replaced with an event.

Previously, when you emptied (not deleted) a course, the notify_local_course_delete method was called, which looked for a local_delete_course method in local/lib.php. The naming of this is a little ambiguous because the course is being emptied, not deleted.

Going forwards, we aim to have two events - course_emptied and course_deleted. Support for the local_delete_course method will be removed.

See http://tracker.moodle.org/browse/MDL-17445 for more info.

Local my moodle overrides

(pending commit)

By default, the My Moodle page shows a course overview in the center column. Some sites might want to replace that with some custom code, or even just some static content. This is very easily accomplished by:

• Creating a local/lib.php
• Putting a function in there, called local_my_moodle.

This function will be called 'instead of (rather than in addition to), the default center column.

Local stickyblocks targets

(pending commit)

In the case where you're developing a heavily customised site, it might happen that you develop a pagetype that has the ability for people to add blocks to. In this case, you might want to also make it stickyblock enabled.

This is easily achieved by:

• Create local/lib.php
• Create a method in there called local_get_sticky_pagetypes that returns an array just like the $pagetypes array at the top of admin/stickyblocks.php.

For example:

function local_get_sticky_pagetypes() {

   return array(
       'custom_pagetype' => array(
           'id' => 'custom_pagetype',
           'lib' => '/local/lib.php',
           'name' => get_string('custom_pagetype', 'local')
       )
   );

}

You then must create a page that extends page_base. Don't forget that if your pagetype is stickyblock enabled, it needs to take this into account in some of its methods. For example:

class custom_pagetype extends page_base {

   // normal page type class

   function url_get_path() {
       global $CFG;
       if (defined('ADMIN_STICKYBLOCKS')) { // admin is editing stickyblocks, not a normal page
           return $CFG->wwwroot . '/admin/stickyblocks.php';
       }
       return ;
   }

   function url_get_parameters() {
       global $CFG;
       if (defined('ADMIN_STICKYBLOCKS')) {
           return array('pt' =>  'custom_pagetype');
       }
   }

}

and map it with page_map_class:

page_map_class('custom_pagetype', 'custom_pagetype');

Local user profile view hook

(pending commit)

Sometimes, it may be desirable to do something like add extra buttons to the bottom of the user's profile page - if you've developed some custom code to perform extra actions on a user, for example. This is very easy to do.

• Create local/lib.php
• Create a function in there, local_user_view.

function local_user_view($user, $course) {

   // capability check

   // extra stuff

}

Local language strings

The only place in the above list that requires an additional language file is the local capabilites. These are expected to be in lang/$lang/local.php and keyed with local:capname.

Additionally, you can of course add lang/$lang/local.php just like an extra language file and call it with the usual get_string('key', 'local', $a) syntax.

There is also the ability to create a special custom lang/{$lang}_local/ directory (eg lang/en_utf8_local/), which contains just the strings that you want to override from the main language pack. Moodle will always look there first before finding the strings in the normal language pack.

This is because, historically, people have wanted to override some strings, typically things like 'course' to become 'module', or similar, and have created custom language packs. But then this forces the users to have this custom pack selected. The use of {$lang}_local is much more lightweight.

Local cron

If the file exists, local/cron.php is included by admin/cron.php every time cron is run.

See also

• CVS:moodle/lib/locallib.php
• Using Moodle Local Customisations forum discussion