Proyectos de Subversion Moodle

<?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 block_multiblock.

 *

 * @package   block_multiblock

 * @copyright 2020 Peter Spicer <peter.spicer@catalyst-eu.net>

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

namespace block_multiblock\privacy;

use context;

use context_block;

use core_privacy\local\metadata\collection;

use core_privacy\local\metadata\provider as metadata_provider;

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\core_userlist_provider as userlist_provider;

use core_privacy\local\request\plugin\provider as plugin_provider;

use core_privacy\local\request\userlist;

/**

 * Privacy Subsystem implementation for block_multiblock.

 *

 * @package   block_multiblock

 * @copyright 2020 Peter Spicer <peter.spicer@catalyst-eu.net>

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class provider implements metadata_provider, userlist_provider, plugin_provider {

    /**

     * Returns information about how block_multiblock stores its data.

     *

     * This plugin implements several interfaces:

     * - The \core_privacy\local\metadata\provider interface - Multiblock manages blocks that might store user data.

     * - The \core_privacy\local\request\core_userlist_provider interface - Multiblock queries dependent blocks for this data.

     * - The \core_privacy\local\request\plugin\provider interface - Multiblock interacts directly with core.

     *

     * @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->link_subsystem('block', 'privacy:metadata:block');

        return $collection;

    }

    /**

     * Get the list of contexts that contain user information for the requested user.

     *

     * @param int $userid The user to lookup.

     * @return contextlist $contextlist The contextlist containing the list of contexts used in this plugin.

     */

    public static function get_contexts_for_userid(int $userid) : contextlist {

        // This won't be the full list of contexts, this is the list of contexts of the multiblock parents.

        // We will resolve the full list out when fetching or pruning actual data.

        // Note that we can only connect blocks to user data when they're in a user context.

        $contextlist = new contextlist;

        $sql = "SELECT c.id

                  FROM {block_instances} b

            INNER JOIN {context} c ON c.instanceid = b.id AND c.contextlevel = :contextblock

            INNER JOIN {context} bpc ON bpc.id = b.parentcontextid

                 WHERE b.blockname = :blockname

                   AND bpc.contextlevel = :contextuser

                   AND bpc.instanceid = :userid";

        $params = [

            'blockname' => 'multiblock',

            'contextblock' => CONTEXT_BLOCK,

            'contextuser' => CONTEXT_USER,

            'userid' => $userid,

        ];

        $contextlist->add_from_sql($sql, $params);

        return $contextlist;

    }

    /**

     * Get the list of users who have data within a context.

     *

     * @param userlist $userlist The userlist containing the list of users who have data in this context/plugin combination.

     */

    public static function get_users_in_context(userlist $userlist) {

        // The users of a given multiblock context are the ones who own it; subblocks just inherit the parent context.

        // By extension this means they inherit the parent owner too.

        $context = $userlist->get_context();

        if (!is_a($context, context_block::class)) {

            return;

        }

        $params = [

            'blockname' => 'multiblock',

            'contextid' => $context->id,

            'contextuser' => CONTEXT_USER,

        ];

        $sql = "SELECT bpc.instanceid AS userid

                  FROM {context} c

                  JOIN {block_instances} bi ON bi.id = c.instanceid AND bi.blockname = :blockname

                  JOIN {context} bpc ON bpc.id = bi.parentcontextid AND bpc.contextlevel = :contextuser

                 WHERE c.id = :contextid";

        $userlist->add_from_sql('userid', $sql, $params);

    }

    /**

     * Export all user data for the specified user, in the specified contexts.

     *

     * Unlike other parts of the privacy provider, this time we actually fetch the sub-block data.

     *

     * @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();

        list($contextsql, $contextparams) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);

        $sql = "SELECT c.id AS contextid, bi.*

                  FROM {context} c

                  JOIN {block_instances} bi ON bi.id = c.instanceid AND c.contextlevel = :contextlevel

                 WHERE bi.blockname = :blockname

                   AND (c.id {$contextsql})";

        $params = [

            'blockname' => 'multiblock',

            'contextlevel' => CONTEXT_BLOCK,

        ];

        $params += $contextparams;

        $multiblocks = $DB->get_recordset_sql($sql, $params);

        $subblockcontexts = [];

        // We need to build contextlists for each of the subblocks, with their aggregate context lists.

        foreach ($multiblocks as $multiblock) {

            $subblock = "SELECT c.id AS contextid, bi.blockname

                           FROM {context} c

                           JOIN {block_instances} bi ON bi.id = c.instanceid AND c.contextlevel = :contextlevel

                          WHERE bi.parentcontextid = :parentcontext";

            $subblockparams = [

                'contextlevel' => CONTEXT_BLOCK,

                'parentcontext' => $multiblock->contextid,

            ];

            // Now step through all the subblocks of this particular block and query it.

            $subblocks = $DB->get_records_sql($subblock, $subblockparams);

            foreach ($subblocks as $subblock) {

                $subblockcontexts['block_' . $subblock->blockname][] = $subblock->contextid;

            }

        }

        foreach ($subblockcontexts as $component => $contexts) {

            $componentcontextlist = new approved_contextlist($user, $component, $contexts);

            $classname = $component . '\\privacy\\provider';

            if (class_exists($classname) && method_exists($classname, 'export_user_data')) {

                $classname::export_user_data($componentcontextlist);

            }

        }

    }

    /**

     * 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) {

        if (!$context instanceof context_block) {

            return;

        }

        // The only way to delete data for the html block is to delete the block instance itself.

        if ($blockinstance = static::get_instance_from_context($context)) {

            blocks_delete_instance($blockinstance);

        }

    }

    /**

     * Delete multiple users within a single context.

     *

     * This will delete the main multiblocks, which will also delete all child blocks.

     *

     * @param approved_userlist $userlist The approved context and user information to delete information for.

     */

    public static function delete_data_for_users(approved_userlist $userlist) {

        $context = $userlist->get_context();

        if (!$context instanceof context_block) {

            return;

        }

        if ($blockinstance = static::get_instance_from_context($context)) {

            blocks_delete_instance($blockinstance);

        }

    }

    /**

     * Delete all user data for the specified user, in the specified contexts.

     *

     * This will delete the main multiblocks, which will also delete all child blocks.

     *

     * @param approved_contextlist $contextlist The approved contexts and user information to delete information for.

     */

    public static function delete_data_for_user(approved_contextlist $contextlist) {

        foreach ($contextlist as $context) {

            if (!$context instanceof context_block) {

                continue;

            }

            if ($blockinstance = static::get_instance_from_context($context)) {

                blocks_delete_instance($blockinstance);

            }

        }

    }

    /**

     * Get the block instance record for the specified context.

     *

     * @param   context_block $context The context to fetch

     * @return  stdClass

     */

    protected static function get_instance_from_context(context_block $context) {

        global $DB;

        return $DB->get_record('block_instances', ['id' => $context->instanceid, 'blockname' => 'multiblock']);

    }

}