MDL-61984 mod_chat: Implement privacy API

mod/chat/classes/privacy/provider.php

@@ -0,0 +1,258 @@
+<?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/>.
+
+/**
+ * Data provider.
+ *
+ * @package    mod_chat
+ * @copyright  2018 Frédéric Massart
+ * @author     Frédéric Massart <fred@branchup.tech>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace mod_chat\privacy;
+defined('MOODLE_INTERNAL') || die();
+
+use context;
+use context_helper;
+use context_module;
+use stdClass;
+use core_privacy\local\metadata\collection;
+use core_privacy\local\request\approved_contextlist;
+use core_privacy\local\request\helper;
+use core_privacy\local\request\transform;
+use core_privacy\local\request\writer;
+
+/**
+ * Data provider class.
+ *
+ * @package    mod_chat
+ * @copyright  2018 Frédéric Massart
+ * @author     Frédéric Massart <fred@branchup.tech>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class provider implements
+    \core_privacy\local\metadata\provider,
+    \core_privacy\local\request\plugin\provider {
+
+    /**
+     * Returns metadata.
+     *
+     * @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('chat_messages', [
+            'userid' => 'privacy:metadata:messages:userid',
+            'message' => 'privacy:metadata:messages:message',
+            'issystem' => 'privacy:metadata:messages:issystem',
+            'timestamp' => 'privacy:metadata:messages:timestamp',
+        ], 'privacy:metadata:messages');
+
+        // The tables chat_messages_current and chat_users are not reported here
+        // because they are considered as short-lived data and are deleted on a
+        // regular basis by cron, or during normal requests. MDL-62006 was raised
+        // to discuss and/or implement support for those tables.
+
+        return $collection;
+    }
+
+    /**
+     * Get the list of contexts that contain user information for the specified user.
+     *
+     * @param int $userid The user to search.
+     * @return contextlist $contextlist The contextlist containing the list of contexts used in this plugin.
+     */
+    public static function get_contexts_for_userid(int $userid) : \core_privacy\local\request\contextlist {
+        $contextlist = new \core_privacy\local\request\contextlist();
+
+        $sql = "
+            SELECT DISTINCT ctx.id
+              FROM {chat} c
+              JOIN {modules} m
+                ON m.name = :chat
+              JOIN {course_modules} cm
+                ON cm.instance = c.id
+               AND cm.module = m.id
+              JOIN {context} ctx
+                ON ctx.instanceid = cm.id
+               AND ctx.contextlevel = :modulelevel
+              JOIN {chat_messages} chm
+                ON chm.chatid = c.id
+             WHERE chm.userid = :userid";
+
+        $params = [
+            'chat' => 'chat',
+            'modulelevel' => CONTEXT_MODULE,
+            '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) {
+        global $DB;
+
+        $user = $contextlist->get_user();
+        $userid = $user->id;
+        $cmids = array_reduce($contextlist->get_contexts(), function($carry, $context) {
+            if ($context->contextlevel == CONTEXT_MODULE) {
+                $carry[] = $context->instanceid;
+            }
+            return $carry;
+        }, []);
+        if (empty($cmids)) {
+            return;
+        }
+
+        $chatidstocmids = static::get_chat_ids_to_cmids_from_cmids($cmids);
+        $chatids = array_keys($chatidstocmids);
+
+        // Export the messages.
+        list($insql, $inparams) = $DB->get_in_or_equal($chatids, SQL_PARAMS_NAMED);
+        $params = array_merge($inparams, ['userid' => $userid]);
+        $recordset = $DB->get_recordset_select('chat_messages', "chatid $insql AND userid = :userid", $params, 'timestamp, id');
+        static::recordset_loop_and_export($recordset, 'chatid', [], function($carry, $record) use ($user, $chatidstocmids) {
+            $message = $record->message;
+            if ($record->issystem) {
+                $message = get_string('message' . $record->message, 'mod_chat', fullname($user));
+            }
+            $carry[] = [
+                'message' => $message,
+                'sent_at' => transform::datetime($record->timestamp),
+                'is_system_generated' => transform::yesno($record->issystem),
+            ];
+            return $carry;
+
+        }, function($chatid, $data) use ($user, $chatidstocmids) {
+            $context = context_module::instance($chatidstocmids[$chatid]);
+            $contextdata = helper::get_context_data($context, $user);
+            $finaldata = (object) array_merge((array) $contextdata, ['messages' => $data]);
+            helper::export_context_files($context, $user);
+            writer::with_context($context)->export_data([], $finaldata);
+        });
+    }
+
+    /**
+     * 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) {
+        global $DB;
+
+        if ($context->contextlevel != CONTEXT_MODULE) {
+            return;
+        }
+
+        $chatid = get_coursemodule_from_id('chat', $context->instanceid, 0, false, MUST_EXIST)->instance;
+        $DB->delete_records_select('chat_messages', 'chatid = :chatid', ['chatid' => $chatid]);
+        $DB->delete_records_select('chat_messages_current', 'chatid = :chatid', ['chatid' => $chatid]);
+        $DB->delete_records_select('chat_users', 'chatid = :chatid', ['chatid' => $chatid]);
+    }
+
+    /**
+     * 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) {
+        global $DB;
+
+        $userid = $contextlist->get_user()->id;
+        $cmids = array_reduce($contextlist->get_contexts(), function($carry, $context) {
+            if ($context->contextlevel == CONTEXT_MODULE) {
+                $carry[] = $context->instanceid;
+            }
+            return $carry;
+        }, []);
+        if (empty($cmids)) {
+            return;
+        }
+
+        $chatidstocmids = static::get_chat_ids_to_cmids_from_cmids($cmids);
+        $chatids = array_keys($chatidstocmids);
+
+        list($insql, $inparams) = $DB->get_in_or_equal($chatids, SQL_PARAMS_NAMED);
+        $sql = "chatid $insql AND userid = :userid";
+        $params = array_merge($inparams, ['userid' => $userid]);
+
+        $DB->delete_records_select('chat_messages', $sql, $params);
+        $DB->delete_records_select('chat_messages_current', $sql, $params);
+        $DB->delete_records_select('chat_users', $sql, $params);
+    }
+
+    /**
+     * Return a dict of chat IDs mapped to their course module ID.
+     *
+     * @param array $cmids The course module IDs.
+     * @return array In the form of [$chatid => $cmid].
+     */
+    protected static function get_chat_ids_to_cmids_from_cmids(array $cmids) {
+        global $DB;
+        list($insql, $inparams) = $DB->get_in_or_equal($cmids, SQL_PARAMS_NAMED);
+        $sql = "
+            SELECT c.id, cm.id AS cmid
+              FROM {chat} c
+              JOIN {modules} m
+                ON m.name = :chat
+              JOIN {course_modules} cm
+                ON cm.instance = c.id
+               AND cm.module = m.id
+             WHERE cm.id $insql";
+        $params = array_merge($inparams, ['chat' => 'chat']);
+        return $DB->get_records_sql_menu($sql, $params);
+    }
+
+    /**
+     * Loop and export from a recordset.
+     *
+     * @param moodle_recordset $recordset The recordset.
+     * @param string $splitkey The record key to determine when to export.
+     * @param mixed $initial The initial data to reduce from.
+     * @param callable $reducer The function to return the dataset, receives current dataset, and the current record.
+     * @param callable $export The function to export the dataset, receives the last value from $splitkey and the dataset.
+     * @return void
+     */
+    protected static function recordset_loop_and_export(\moodle_recordset $recordset, $splitkey, $initial,
+            callable $reducer, callable $export) {
+
+        $data = $initial;
+        $lastid = null;
+
+        foreach ($recordset as $record) {
+            if ($lastid && $record->{$splitkey} != $lastid) {
+                $export($lastid, $data);
+                $data = $initial;
+            }
+            $data = $reducer($data, $record);
+            $lastid = $record->{$splitkey};
+        }
+        $recordset->close();
+
+        if (!empty($lastid)) {
+            $export($lastid, $data);
+        }
+    }
+
+}

mod/chat/lang/en/chat.php

@@ -118,6 +118,11 @@
 $string['pastchats'] = 'Past chat sessions';
 $string['pluginadministration'] = 'Chat administration';
 $string['pluginname'] = 'Chat';
+$string['privacy:metadata:messages'] = 'A record of the messages sent during a chat session';
+$string['privacy:metadata:messages:issystem'] = 'Whether the message is a system-generated message';
+$string['privacy:metadata:messages:message'] = 'The message';
+$string['privacy:metadata:messages:timestamp'] = 'The time at which the message was sent';
+$string['privacy:metadata:messages:userid'] = 'The user ID of the author of the message';
 $string['refreshroom'] = 'Refresh room';
 $string['refreshuserlist'] = 'Refresh user list';
 $string['removemessages'] = 'Remove all messages';