moodle-privacy-gdpr

name	moodle-privacy-gdpr
description	Use when implementing or reviewing the Moodle privacy provider (GDPR) — null_provider vs request\plugin\provider, get_metadata, export_user_data, delete_data_for_user_in_context, delete_data_for_users, get_contexts_for_userid, get_users_in_context, subsystem links, and core_userlist_provider.

Moodle Privacy / GDPR

Overview

Every Moodle plugin must declare a privacy provider in classes/privacy/provider.php. The provider tells Moodle what user data the plugin stores so that the data export and deletion workflows (Site admin > Users > Privacy) work correctly. Without a provider, the privacy compliance report flags the plugin.

When to Use

• Creating any new plugin (mandatory)
• Adding a DB table that stores user-identifying data
• Reviewing privacy compliance for plugin directory submission
• Responding to a GDPR data subject request

Skip when: the plugin only ships static files / no DB tables — still needs null_provider though.

Decision tree

Plugin stores no user-identifying data?
└── implement \core_privacy\local\metadata\null_provider

Plugin stores user data, all of it via core subsystems (files, comments, ratings)?
└── implement \core_privacy\local\metadata\provider
        + link subsystems via add_subsystem_link

Plugin stores user data in its own tables?
└── implement \core_privacy\local\metadata\provider
       + \core_privacy\local\request\plugin\provider
       + \core_privacy\local\request\core_userlist_provider

Null provider (no user data)

<?php
namespace local_example\privacy;
defined('MOODLE_INTERNAL') || die();

class provider implements \core_privacy\local\metadata\null_provider {
    public static function get_reason(): string {
        return 'privacy:metadata';
    }
}

Lang string lang/en/local_example.php:

$string['privacy:metadata'] = 'The Example plugin does not store any personal data.';

Full provider (plugin tables hold user data)

<?php
namespace local_example\privacy;
defined('MOODLE_INTERNAL') || die();

use core_privacy\local\metadata\collection;
use core_privacy\local\request\approved_contextlist;
use core_privacy\local\request\approved_userlist;
use core_privacy\local\request\contextlist;
use core_privacy\local\request\userlist;
use core_privacy\local\request\writer;

class provider implements
    \core_privacy\local\metadata\provider,
    \core_privacy\local\request\plugin\provider,
    \core_privacy\local\request\core_userlist_provider {

    public static function get_metadata(collection $collection): collection {
        $collection->add_database_table('local_example_items', [
            'userid'      => 'privacy:metadata:items:userid',
            'name'        => 'privacy:metadata:items:name',
            'content'     => 'privacy:metadata:items:content',
            'timecreated' => 'privacy:metadata:items:timecreated',
        ], 'privacy:metadata:items');

        // External system call:
        $collection->add_external_location_link('moodleorg', [
            'username' => 'privacy:metadata:moodleorg:username',
        ], 'privacy:metadata:moodleorg');

        // Subsystem link (files, comments):
        $collection->add_subsystem_link('core_files', [], 'privacy:metadata:filepurpose');

        return $collection;
    }

    public static function get_contexts_for_userid(int $userid): contextlist {
        $contextlist = new contextlist();
        $sql = "SELECT ctx.id
                  FROM {local_example_items} i
                  JOIN {context} ctx ON ctx.contextlevel = :ctxlevel
                                    AND ctx.instanceid = i.courseid
                 WHERE i.userid = :userid";
        $contextlist->add_from_sql($sql, [
            'ctxlevel' => CONTEXT_COURSE,
            'userid'   => $userid,
        ]);
        return $contextlist;
    }

    public static function get_users_in_context(userlist $userlist): void {
        $context = $userlist->get_context();
        if ($context->contextlevel !== CONTEXT_COURSE) {
            return;
        }
        $sql = "SELECT userid FROM {local_example_items} WHERE courseid = :courseid";
        $userlist->add_from_sql('userid', $sql, ['courseid' => $context->instanceid]);
    }

    public static function export_user_data(approved_contextlist $contextlist): void {
        global $DB;
        $user = $contextlist->get_user();
        foreach ($contextlist->get_contexts() as $context) {
            if ($context->contextlevel !== CONTEXT_COURSE) {
                continue;
            }
            $rows = $DB->get_records('local_example_items', [
                'courseid' => $context->instanceid,
                'userid'   => $user->id,
            ]);
            $data = (object)[
                'items' => array_map(fn($r) => [
                    'name'        => $r->name,
                    'content'     => $r->content,
                    'timecreated' => \core_privacy\local\request\transform::datetime($r->timecreated),
                ], $rows),
            ];
            writer::with_context($context)->export_data(
                [get_string('pluginname', 'local_example')],
                $data
            );
        }
    }

    public static function delete_data_for_all_users_in_context(\context $context): void {
        global $DB;
        if ($context->contextlevel !== CONTEXT_COURSE) {
            return;
        }
        $DB->delete_records('local_example_items', ['courseid' => $context->instanceid]);
    }

    public static function delete_data_for_user(approved_contextlist $contextlist): void {
        global $DB;
        $user = $contextlist->get_user();
        foreach ($contextlist->get_contexts() as $context) {
            if ($context->contextlevel !== CONTEXT_COURSE) {
                continue;
            }
            $DB->delete_records('local_example_items', [
                'courseid' => $context->instanceid,
                'userid'   => $user->id,
            ]);
        }
    }

    public static function delete_data_for_users(approved_userlist $userlist): void {
        global $DB;
        $context = $userlist->get_context();
        if ($context->contextlevel !== CONTEXT_COURSE) {
            return;
        }
        [$insql, $params] = $DB->get_in_or_equal($userlist->get_userids(), SQL_PARAMS_NAMED);
        $params['courseid'] = $context->instanceid;
        $DB->delete_records_select('local_example_items',
            "courseid = :courseid AND userid $insql", $params);
    }
}

Required lang strings

$string['privacy:metadata']                       = 'Stores user attendance items.';
$string['privacy:metadata:items']                 = 'Information about user-created items.';
$string['privacy:metadata:items:userid']          = 'The ID of the user who created the item.';
$string['privacy:metadata:items:name']            = 'The name of the item.';
$string['privacy:metadata:items:content']         = 'The body of the item.';
$string['privacy:metadata:items:timecreated']     = 'The time the item was created.';
$string['privacy:metadata:moodleorg']             = 'Items synced to moodle.org.';
$string['privacy:metadata:moodleorg:username']    = 'The username sent to moodle.org.';
$string['privacy:metadata:filepurpose']           = 'Files attached to items.';

Every column listed in add_database_table and every external location field needs a string.

Subsystem links

If you use a core subsystem that stores user data on your behalf:

Subsystem	Constant
Files	'core_files'
Comments	'core_comment'
Ratings	'core_rating'
Tags	'core_tag'
Plagiarism	'core_plagiarism'
Portfolio	'core_portfolio'
Logs	'core_log'
Backup	'core_backup'

$collection->add_subsystem_link('core_files', [], 'privacy:metadata:filepurpose');

The subsystem provider handles export/delete; you only declare the link.

Activity module specifics

Activities also implement \mod_<name>\privacy\provider with cm-context awareness. Use \core_privacy\local\request\helper::get_context_data($context, $user) to include the activity instance metadata in exports.

Testing the provider

// tests/privacy/provider_test.php
use core_privacy\tests\provider_testcase;

final class provider_test extends provider_testcase {
    public function test_get_contexts_for_userid(): void {
        $this->resetAfterTest();
        // ... set up data ...
        $contextlist = provider::get_contexts_for_userid($user->id);
        $this->assertCount(1, $contextlist);
    }
}

Useful core helper: \core_privacy\tests\provider_testcase provides export_context_data_for_user, delete_data_for_user, etc.

Run all privacy tests:

vendor/bin/phpunit --group core_privacy

Compliance report

Site admin > Users > Privacy and policies > Plugin privacy registry. Lists every component with its declared metadata. Plugins missing a provider show as Not yet implemented (red) — fails moodle.org plugin directory review.

Common Mistakes

Mistake	Fix
No provider at all	Add at minimum null_provider
null_provider when DB stores user data	Switch to full provider
Missing core_userlist_provider	Required since Moodle 3.6+
add_database_table columns missing lang strings	Every field needs a privacy:metadata:... string
delete_data_for_user_in_context (old name)	Method is delete_data_for_user(approved_contextlist)
Forgetting add_subsystem_link('core_files') when using files	Add — core files provider handles deletion
Returning transform::datetime from non-datetime column	Only for unix timestamps
delete_data_for_all_users_in_context not honoring context level	Always check $context->contextlevel first
Missing in plugin directory review	All providers required for moodle.org listing

References

• Privacy API: https://moodledev.io/docs/apis/subsystems/privacy
• Implementing the API: https://moodledev.io/docs/apis/subsystems/privacy/api
• Subsystems: https://moodledev.io/docs/apis/subsystems/privacy/api#subsystems
• Testing: https://moodledev.io/docs/apis/subsystems/privacy/api#testing