Local plugins

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Local customisations
Project state	Implemented
Tracker issue	MDL-17376, MDL-16438
Discussion	http://moodle.org/mod/forum/discuss.php?d=126017 http://moodle.org/mod/forum/discuss.php?d=86903
Assignee	Petr Škoda (škoďák), some parts were originally proposed and implemented in 1.9 by Penny Leach

Moodle 2.0

The recommended way to add new functionality to Moodle is to create a new standard plugin (module, block, auth, enrol, etc.).The /local/ plugins are mostly suitable for things that do not fit standard plugins.

Custom /local/ plugins

Local plugins are used in cases when no standard plugin fits, examples are:

• event consumers communicating with external systems
• custom definitions of web services and external functions
• applications that extend moodle at the system level (hub server, amos server, etc.)
• new database tables used in core hacks (discouraged)
• new capability definitions used in core hacks
• custom admin settings
• extending the navigation block with custom menus [1]

Standard plugin features:

• /local/xxx/version.php - version of script (must be incremented after changes)
• /local/xxx/db/install.xml - executed during install (new version.php found)
• /local/xxx/db/install.php - executed right after install.xml
• /local/xxx/db/uninstall.php - executed during uninstallation
• /local/xxx/db/upgrade.php - executed after version.php change
• /local/xxx/db/access.php - definition of capabilities
• /local/xxx/db/events.php - event handlers and subscripts
• /local/xxx/db/messages.php - messaging registration
• /local/xxx/db/external.php - web services and external functions descriptions
• /local/xxx/cron.php - cron job, run at the interval defined in version.php. Alternatively, you can define local_xxx_cron() in lib.php. Between those two methods, the lib.php one is preferred. But both of them are considered legacy and have been deprecated for Moodle 3.5 (MDL-52846) and will be deleted for Moodle 3.9 (MDL-61165). [More info here]. They are being replaced with the Task_API.
• /local/xxx/lang/en/local_pluginname.php - language file
• /local/xxx/lib.php - function library, automatically included with by config.php. Hook functions local_xxx_extend_navigation() and local_xxx_extend_settings_navigation() can be used to add items to the navigation and settings blocks
• /local/xxx/settings.php - configuration options. These get added to the admin menu.

The xxx is used instead of your local plugin name, plugins of the same type are installed/upgraded in alphabetical order.

List of differences from normal plugins:

• always executed last during install/upgrade - guaranteed by order of plugins in

  get_plugin_types()
  

• are expected to use event handlers - events are intended for communication core-->plugins only, local plugins are the best candidates for event handlers
• can add admin settings to any settings page - loaded last when constructing admin tree
• do not need to have any UI - other plugins are usually visible somewhere
• some extra hooks (not implemented yet)

/local/xxx/db/messages.php

Example File Structure:

<?php

/**
 * Defines message providers (types of messages being sent)
 *
 * @package mod-forum
 * @copyright  1999 onwards  Martin Dougiamas  http://moodle.com
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

$messageproviders = array (

/// Ordinary single forum posts
    'posts' => array (
    )

);

Other /local/ customisation files

Customised site defaults

Different default site settings can be stored in file /local/defaults.php. These new defaults are used during installation, upgrade and later are displayed as default values in admin settings. This means that the content of the defaults files is usually updated BEFORE installation or upgrade.

These customised defaults are useful especially when using CLI tools for installation and upgrade.

Sample /local/defaults.php file content:

<?php
$defaults['moodle']['forcelogin'] = 1;  // new default for $CFG->forcelogin
$defaults['scorm']['maxgrade'] = 20;    // default for get_config('scorm', 'maxgrade')
$defaults['moodlecourse']['numsections'] = 11;
$defaults['moodle']['hiddenuserfields'] = array('city', 'country');

First bracket contains string from column plugin of config_plugins table. Second bracket is the name of setting. In the admin settings UI the plugin and name of setting is separated by "|".

The values usually correspond to the raw string in config table, with the exception of comma separated lists that are usually entered as real arrays.

Please note that not all settings are converted to admin_tree, they are mostly intended to be set directly in config.php.

2.0 pre-upgrade script

You can use /local/upgrade_pre20.php script for any code that needs to be executed before the main upgrade to 2.0. Most probably this will be used for undoing of old hacks that would otherwise break normal 2.0 upgrade.

This file is just included directly, there does not need to be any function inside. If the execution stops the script is executed again during the next upgrade. The first execution of lib/db/upgrade.php increments the version number and the pre upgrade script is not executed any more.

Customisations outside of /local/ directory

Forced settings

Sometimes it is useful to force some settings and prevent any changes of these settings via the standard admin UI. It is possible to hardcode these settings in config.php.

In case of course settings it is very simply, the values are assigned directly to $CFG properties. In case of plugins the values are specified in a multidimensional array in $CFG->force_plugin_settings.

Sample code in config.php

$CFG->allowobjectembed = 0;
$CFG->forced_plugin_settings = array('page'=>array('displayoptions'=>5, 'requiremodintro'=>1), 'folder'=>array('requiremodintro'=>1));

Local language customisations

Moodle supports other type of local customisation of standard language packs. If you want to create your own language pack based on another language create new dataroot directory with "_local" suffix, for example following file with content changes string "Login" to "Sign in": moodledata/lang/en_local

<?php
  $string['login'] = 'Sign in';

See also https://docs.moodle.org/en/Language_editing

Custom script injection

Very old customisation option that allows you to modify scripts by injecting code right after the require 'config.php' call.

This setting is enabled by manually setting $CFG->customscripts variable in config.php script. The value is expected to be full path to directory with the same structure as dirroot. Please note this hack only affects files that actually include the config.php!

Examples

• disable one specific moodle page without code modification
• alter page parameters on the fly

Direct code modifications

This is usually the last resort, if possible do not do it. And if you still do it use some version control system (preferably git).

Direct database modifications

Very strongly discouraged! Sometimes field lengths may be modified without side effects. Adding or removing of db fields will most probably cause major problems during future upgrades. New database tables should be added only from plugins.

Examples

Adding an element to the settings menu

In local/*pluginname*/lib.php, define a function named local_*pluginname*_extend_settings_navigation, this will get called when Moodle builds the settings block. This example adds a link to the bottom of the course administration section of the settings block.

function local_myplugin_extend_settings_navigation($settingsnav, $context) {
    global $CFG, $PAGE;

    // Only add this settings item on non-site course pages.
    if (!$PAGE->course or $PAGE->course->id == 1) {
        return;
    }

    // Only let users with the appropriate capability see this settings item.
    if (!has_capability('moodle/backup:backupcourse', context_course::instance($PAGE->course->id))) {
        return;
    }

    if ($settingnode = $settingsnav->find('courseadmin', navigation_node::TYPE_COURSE)) {
        $strfoo = get_string('foo', 'local_myplugin');
        $url = new moodle_url('/local/myplugin/foo.php', array('id' => $PAGE->course->id));
        $foonode = navigation_node::create(
            $strfoo,
            $url,
            navigation_node::NODETYPE_LEAF,
            'myplugin',
            'myplugin',
            new pix_icon('t/addcontact', $strfoo)
        );
        if ($PAGE->url->compare($url, URL_MATCH_BASE)) {
            $foonode->make_active();
        }
        $settingnode->add_node($foonode);
    }
}

Removing the "Site Home" link from the navigation menu

function local_xxx_extend_navigation(global_navigation $navigation) {
    if ($home = $navigation->find('home', global_navigation::TYPE_SETTING)) {
        $home->remove();
    }
}

Adding Site Wide Settings For Your Local Plugin

If you need to add site wide settings for your local plugin, perhaps connection details for an API, you will need to do something similar to the below in your settings file (local/yourplugin/settings.php)

// Ensure the configurations for this site are set
if ( $hassiteconfig ){

	// Create the new settings page
	// - in a local plugin this is not defined as standard, so normal $settings->methods will throw an error as
	// $settings will be NULL
	$settings = new admin_settingpage( 'local_yourplugin', 'Your Settings Page Title' );

	// Create 
	$ADMIN->add( 'localplugins', $settings );

	// Add a setting field to the settings for this page
	$settings->add( new admin_setting_configtext(
		
		// This is the reference you will use to your configuration
		'local_yourplugin/apikey',
	
		// This is the friendly title for the config, which will be displayed
		'External API: Key',
	
		// This is helper text for this config field
		'This is the key used to access the External API',
	
		// This is the default value
		'No Key Defined',
	
		// This is the type of Parameter this config is
		PARAM_TEXT
	
	) );

}

Local customisations in previous versions

Previous versions include only partial support for customisations in /local/ directory.

List of local customisations in 1.9.x:

• /local/cron.php - custom cron jobs
• /local/settings.php - custom admin settings
• /local/db/upgrade.php - general modifications
• /local/lang/* - custom strings
• /local/lib.php - local_delete_course()

Migration from old 1.9.x /local/:

• local/*
  

  needs to be copied to new directory

• local/xxxx/db/install.php
  

  is intended for first installation, originally everything was in upgrade.php
• events are used instead of hooks
• upgrade code needs to migrate old settings, events, etc. directly in core db tables - such as change component strings and capability names from db/install.php or manually before/after upgrade

See also

• Extending navigation block
• Using Moodle Local Customisations forum discussion
• Local customisation (Moodle 1.9)