MDL-62318 core_group: Add implementation of privacy API

group/classes/privacy/provider.php

@@ -0,0 +1,242 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Privacy Subsystem implementation for core_group.
+ *
+ * @package    core_group
+ * @category   privacy
+ * @copyright  2018 Shamim Rezaie <shamim@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_group\privacy;
+
+defined('MOODLE_INTERNAL') || die();
+
+use core_privacy\local\metadata\collection;
+use core_privacy\local\request\approved_contextlist;
+use core_privacy\local\request\contextlist;
+use core_privacy\local\request\transform;
+
+/**
+ * Privacy Subsystem implementation for core_group.
+ *
+ * @copyright  2018 Shamim Rezaie <shamim@moodle.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements
+        // Groups store user data.
+        \core_privacy\local\metadata\provider,
+
+        // The group subsystem contains user's group memberships.
+        \core_privacy\local\request\subsystem\provider,
+
+        // The group subsystem can provide information to other plugins.
+        \core_privacy\local\request\subsystem\plugin_provider {
+
+    /**
+     * Returns meta data about this system.
+     *
+     * @param   collection $collection The initialised collection to add items to.
+     * @return  collection A listing of user data stored through this system.
+     */
+    public static function get_metadata(collection $collection) : collection {
+        $collection->add_database_table('groups_members', [
+            'groupid' => 'privacy:metadata:groups:groupid',
+            'userid' => 'privacy:metadata:groups:userid',
+            'timeadded' => 'privacy:metadata:groups:timeadded',
+        ], 'privacy:metadata:groups');
+
+        return $collection;
+    }
+
+    /**
+     * Writes user data to the writer for the user to download.
+     *
+     * @param \context  $context    The context to export data for.
+     * @param string    $component  The component that is calling this function. Empty string means no component.
+     * @param array     $subcontext The sub-context in which to export this data.
+     * @param int       $itemid     Optional itemid associated with component.
+     */
+    public static function export_groups(\context $context, string $component, array $subcontext = [], int $itemid = 0) {
+        global $DB, $USER;
+
+        if (!$context instanceof \context_course) {
+            return;
+        }
+
+        $subcontext[] = get_string('groups', 'core_group');
+
+        $sql = "SELECT gm.id, gm.timeadded, gm.userid, g.name
+                  FROM {groups_members} gm
+                  JOIN {groups} g ON gm.groupid = g.id
+                 WHERE g.courseid = :courseid
+                       AND gm.component = :component
+                       AND gm.userid = :userid";
+        $params = [
+            'courseid'  => $context->instanceid,
+            'component' => $component,
+            'userid'    => $USER->id
+        ];
+
+        if ($itemid) {
+            $sql .= ' AND gm.itemid = :itemid';
+            $params['itemid'] = $itemid;
+        }
+
+        $groups = $DB->get_records_sql($sql, $params);
+
+        $groups = array_map(function($group) {
+            return (object) [
+                'name' => format_string($group->name),
+                'timeadded' => transform::datetime($group->timeadded),
+            ];
+        }, $groups);
+
+        if (!empty($groups)) {
+            \core_privacy\local\request\writer::with_context($context)
+                    ->export_data($subcontext, (object) [
+                        'groups' => $groups,
+                    ]);
+        }
+    }
+
+    /**
+     * Deletes all group memberships for a specified context and component.
+     *
+     * @param \context  $context    Details about which context to delete group memberships for.
+     * @param string    $component  Component to delete. Empty string means no component (manual group memberships).
+     * @param int       $itemid     Optional itemid associated with component.
+     */
+    public static function delete_groups_for_all_users(\context $context, string $component, int $itemid = 0) {
+        global $DB;
+
+        if (!$context instanceof \context_course) {
+            return;
+        }
+
+        if (!$DB->record_exists('groups', ['courseid' => $context->instanceid])) {
+            return;
+        }
+
+        $select = "component = :component AND groupid IN (SELECT g.id FROM {groups} g WHERE courseid = :courseid)";
+        $params = ['component' => $component, 'courseid' => $context->instanceid];
+
+        if ($itemid) {
+            $select .= ' AND itemid = :itemid';
+            $params['itemid'] = $itemid;
+        }
+
+        $DB->delete_records_select('groups_members', $select, $params);
+    }
+
+    /**
+     * Deletes all records for a user from a list of approved contexts.
+     *
+     * @param approved_contextlist  $contextlist    Contains the user ID and a list of contexts to be deleted from.
+     * @param string                $component      Component to delete from. Empty string means no component (manual memberships).
+     * @param int                   $itemid         Optional itemid associated with component.
+     */
+    public static function delete_groups_for_user(approved_contextlist $contextlist, string $component, int $itemid = 0) {
+        global $DB;
+
+        $userid = $contextlist->get_user()->id;
+
+        $contextids = $contextlist->get_contextids();
+
+        if (!$contextids) {
+            return;
+        }
+
+        list($contextsql, $contextparams) = $DB->get_in_or_equal($contextids, SQL_PARAMS_NAMED);
+        $contextparams += ['contextcourse' => CONTEXT_COURSE];
+        $groupselect = "SELECT g.id
+                          FROM {groups} g
+                          JOIN {context} ctx ON g.courseid = ctx.instanceid AND ctx.contextlevel = :contextcourse
+                         WHERE ctx.id $contextsql";
+
+        if (!$DB->record_exists_sql($groupselect, $contextparams)) {
+            return;
+        }
+
+        $select = "userid = :userid AND component = :component AND groupid IN ({$groupselect})";
+        $params = ['userid' => $userid, 'component' => $component] + $contextparams;
+
+        if ($itemid) {
+            $select .= ' AND itemid = :itemid';
+            $params['itemid'] = $itemid;
+        }
+
+        $DB->delete_records_select('groups_members', $select, $params);
+    }
+
+    /**
+     * Get the list of contexts that contain user information for the specified user.
+     *
+     * @param   int $userid The user to search.
+     * @return  contextlist The contextlist containing the list of contexts used in this plugin.
+     */
+    public static function get_contexts_for_userid(int $userid) : contextlist {
+        $contextlist = new contextlist();
+
+        $sql = "SELECT ctx.id
+                  FROM {groups_members} gm
+                  JOIN {groups} g ON gm.groupid = g.id
+                  JOIN {context} ctx ON g.courseid = ctx.instanceid AND ctx.contextlevel = :contextcourse
+                 WHERE gm.userid = :userid";
+
+        $params = [
+            'contextcourse' => CONTEXT_COURSE,
+            'userid'        => $userid
+        ];
+
+        $contextlist->add_from_sql($sql, $params);
+
+        return $contextlist;
+    }
+
+    /**
+     * Export all user data for the specified user, in the specified contexts.
+     *
+     * @param approved_contextlist $contextlist The approved contexts to export information for.
+     */
+    public static function export_user_data(approved_contextlist $contextlist) {
+        $contexts = $contextlist->get_contexts();
+
+        foreach ($contexts as $context) {
+            static::export_groups($context, '');
+        }
+    }
+
+    /**
+     * Delete all data for all users in the specified context.
+     *
+     * @param context $context The specific context to delete data for.
+     */
+    public static function delete_data_for_all_users_in_context(\context $context) {
+        static::delete_groups_for_all_users($context, '');
+    }
+
+    /**
+     * Delete all user data for the specified user, in the specified contexts.
+     *
+     * @param approved_contextlist $contextlist The approved contexts and user information to delete information for.
+     */
+    public static function delete_data_for_user(approved_contextlist $contextlist) {
+        static::delete_groups_for_user($contextlist, '');
+    }
+}