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 core_question.

 *

 * @package    core_question

 * @category   privacy

 * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>

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

 */

namespace core_question\privacy;

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\transform;

use core_privacy\local\request\userlist;

use core_privacy\local\request\writer;

defined('MOODLE_INTERNAL') || die();

require_once($CFG->libdir . '/questionlib.php');

require_once($CFG->dirroot . '/question/format.php');

require_once($CFG->dirroot . '/question/editlib.php');

require_once($CFG->dirroot . '/question/engine/datalib.php');

/**

 * Privacy Subsystem implementation for core_question.

 *

 * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>

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

 */

class provider implements

    // This component has data.

    // We need to return all question information where the user is

    // listed in either the question.createdby or question.modifiedby fields.

    // We may also need to fetch this informtion from individual plugins in some cases.

    // e.g. to fetch the full and other question-specific meta-data.

    \core_privacy\local\metadata\provider,

    // This is a subsysytem which provides information to core.

    \core_privacy\local\request\subsystem\provider,

    // This is a subsysytem which provides information to plugins.

    \core_privacy\local\request\subsystem\plugin_provider,

    // This plugin is capable of determining which users have data within it.

    \core_privacy\local\request\core_userlist_provider,

    // This plugin is capable of determining which users have data within it for the plugins it provides data to.

    \core_privacy\local\request\shared_userlist_provider

{

    /**

     * Describe the types of data stored by the question subsystem.

     *

     * @param   collection  $items  The collection to add metadata to.

     * @return  collection  The array of metadata

     */

    public static function get_metadata(collection $items): collection {

        // Other tables link against it.

        // The 'question_usages' table does not contain any user data.

        // The table links the but doesn't store itself.

        // The 'question_attempts' table contains data about question attempts.

        // It does not contain any user ids - these are stored by the caller.

        $items->add_database_table('question_attempts', [

            'flagged'           => 'privacy:metadata:database:question_attempts:flagged',

            'responsesummary'   => 'privacy:metadata:database:question_attempts:responsesummary',

            'timemodified'      => 'privacy:metadata:database:question_attempts:timemodified',

        ], 'privacy:metadata:database:question_attempts');;

        // The 'question_attempt_steps' table contains data about changes to the state of a question attempt.

        $items->add_database_table('question_attempt_steps', [

            'state'             => 'privacy:metadata:database:question_attempt_steps:state',

            'timecreated'       => 'privacy:metadata:database:question_attempt_steps:timecreated',

            'fraction'          => 'privacy:metadata:database:question_attempt_steps:fraction',

            'userid'            => 'privacy:metadata:database:question_attempt_steps:userid',

        ], 'privacy:metadata:database:question_attempt_steps');

        // The 'question_attempt_step_data' table contains specific all metadata for each state.

        $items->add_database_table('question_attempt_step_data', [

            'name'              => 'privacy:metadata:database:question_attempt_step_data:name',

            'value'             => 'privacy:metadata:database:question_attempt_step_data:value',

        ], 'privacy:metadata:database:question_attempt_step_data');

        // These are all part of the set of the question definition

        // The 'question' table is used to store instances of each question.

        // It contains a createdby and modifiedby which related to specific users.

        $items->add_database_table('question', [

            'name'              => 'privacy:metadata:database:question:name',

            'questiontext'      => 'privacy:metadata:database:question:questiontext',

            'generalfeedback'   => 'privacy:metadata:database:question:generalfeedback',

            'timecreated'       => 'privacy:metadata:database:question:timecreated',

            'timemodified'      => 'privacy:metadata:database:question:timemodified',

            'createdby'         => 'privacy:metadata:database:question:createdby',

            'modifiedby'        => 'privacy:metadata:database:question:modifiedby',

        ], 'privacy:metadata:database:question');

        // The 'question_answers' table is used to store the set of answers, with appropriate feedback for each question.

        // It does not contain user data.

        // The 'question_hints' table is used to store hints about the correct answer for a question.

        // It does not contain user data.

        // The 'question_categories' table contains structural information about how questions are presented in the UI.

        // It does not contain user data.

        // The 'question_statistics' table contains aggregated statistics about responses.

        // It does not contain any identifiable user data.

        $items->add_database_table('question_bank_entries', [

            'ownerid' => 'privacy:metadata:database:question_bank_entries:ownerid',

        ], 'privacy:metadata:database:question_bank_entries');

        // The question subsystem makes use of the qtype, qformat, and qbehaviour plugin types.

        $items->add_plugintype_link('qtype', [], 'privacy:metadata:link:qtype');

        $items->add_plugintype_link('qformat', [], 'privacy:metadata:link:qformat');

        $items->add_plugintype_link('qbehaviour', [], 'privacy:metadata:link:qbehaviour');

        return $items;

    }

    /**

     * Export the data for all question attempts on this question usage.

     *

     * Where a user is the owner of the usage, then the full detail of that usage will be included.

     * Where a user has been involved in the usage, but it is not their own usage, then only their specific

     * involvement will be exported.

     *

     * @param   int             $userid     The userid to export.

     * @param   \context        $context    The context that the question was used within.

     * @param   array           $usagecontext  The subcontext of this usage.

     * @param   int             $usage      The question usage ID.

     * @param   \question_display_options   $options    The display options used for formatting.

     * @param   bool            $isowner    Whether the user being exported is the user who used the question.

     */

    public static function export_question_usage(

            int $userid,

            \context $context,

            array $usagecontext,

            int $usage,

            \question_display_options $options,

            bool $isowner

        ) {

        // Determine the questions in this usage.

        $quba = \question_engine::load_questions_usage_by_activity($usage);

        $basepath = $usagecontext;

        $questionscontext = array_merge($usagecontext, [

            get_string('questions', 'core_question'),

        ]);

        foreach ($quba->get_attempt_iterator() as $qa) {

            $question = $qa->get_question(false);

            $slotno = $qa->get_slot();

            $questionnocontext = array_merge($questionscontext, [$slotno]);

            if ($isowner) {

                // This user is the overal owner of the question attempt and all data wil therefore be exported.

                //

                // Respect _some_ of the question_display_options to ensure that they don't have access to

                // generalfeedback and mark if the display options prevent this.

                // This is defensible because they can submit questions without completing a quiz and perform an SAR to

                // get prior access to the feedback and mark to improve upon it.

                // Export the response.

                $data = (object) [

                    'name' => $question->name,

                    'question' => $qa->get_question_summary(),

                    'answer' => $qa->get_response_summary(),

                    'timemodified' => transform::datetime($qa->timemodified),

                ];

                if ($options->marks >= \question_display_options::MARK_AND_MAX) {

                    $data->mark = $qa->format_mark($options->markdp);

                }

                if ($options->flags != \question_display_options::HIDDEN) {

                    $data->flagged = transform::yesno($qa->is_flagged());

                }

                if ($options->generalfeedback != \question_display_options::HIDDEN) {

                    $data->generalfeedback = $question->format_generalfeedback($qa);

                }

                if ($options->manualcomment != \question_display_options::HIDDEN) {

                    if ($qa->has_manual_comment()) {

                        // Note - the export of the step data will ensure that the files are exported.

                        // No need to do it again here.

                        list($comment, $commentformat, $step) = $qa->get_manual_comment();

                        $comment = writer::with_context($context)

                            ->rewrite_pluginfile_urls(

                                $questionnocontext,

                                'question',

                                'response_bf_comment',

                                $step->get_id(),

                                $comment

                            );

                        $data->comment = $qa->get_behaviour(false)->format_comment($comment, $commentformat);

                    }

                }

                writer::with_context($context)

                    ->export_data($questionnocontext, $data);

                // Export the step data.

                static::export_question_attempt_steps($userid, $context, $questionnocontext, $qa, $options, $isowner);

            }

        }

    }

    /**

     * Export the data for each step transition for each question in each question attempt.

     *

     * Where a user is the owner of the usage, then all steps in the question usage will be exported.

     * Where a user is not the owner, but has been involved in the usage, then only their specific

     * involvement will be exported.

     *

     * @param   int                 $userid     The user to export for

     * @param   \context            $context    The context that the question was used within.

     * @param   array               $questionnocontext  The subcontext of this question number.

     * @param   \question_attempt   $qa         The attempt being checked

     * @param   \question_display_options   $options    The display options used for formatting.

     * @param   bool                $isowner    Whether the user being exported is the user who used the question.

     */

    public static function export_question_attempt_steps(

            int $userid,

            \context $context,

            array $questionnocontext,

            \question_attempt $qa,

            \question_display_options $options,

            $isowner

        ) {

        $attemptdata = (object) [

                'steps' => [],

            ];

        $stepno = 0;

        foreach ($qa->get_step_iterator() as $i => $step) {

            $stepno++;

            if ($isowner || ($step->get_user_id() != $userid)) {

                // The user is the owner, or the author of the step.

                $restrictedqa = new \question_attempt_with_restricted_history($qa, $i, null);

                $stepdata = (object) [

                    // Note: Do not include the user here.

                    'time' => transform::datetime($step->get_timecreated()),

                    'action' => $qa->summarise_action($step),

                ];

                if ($options->marks >= \question_display_options::MARK_AND_MAX) {

                    $stepdata->mark = $qa->format_fraction_as_mark($step->get_fraction(), $options->markdp);

                }

                if ($options->correctness != \question_display_options::HIDDEN) {

                    $stepdata->state = $restrictedqa->get_state_string($options->correctness);

                }

                if ($step->has_behaviour_var('comment')) {

                    $comment = $step->get_behaviour_var('comment');

                    $commentformat = $step->get_behaviour_var('commentformat');

                    if (empty(trim($comment))) {

                        // Skip empty comments.

                        continue;

                    }

                    // Format the comment.

                    $comment = writer::with_context($context)

                        ->rewrite_pluginfile_urls(

                            $questionnocontext,

                            'question',

                            'response_bf_comment',

                            $step->get_id(),

                            $comment

                        );

                    // Export any files associated with the comment files area.

                    writer::with_context($context)

                        ->export_area_files(

                            $questionnocontext,

                            'question',

                            "response_bf_comment",

                            $step->get_id()

                        );

                    $stepdata->comment = $qa->get_behaviour(false)->format_comment($comment, $commentformat);

                }

                // Export any response files associated with this step.

                foreach (\question_engine::get_all_response_file_areas() as $filearea) {

                    writer::with_context($context)

                        ->export_area_files(

                                $questionnocontext,

                                'question',

                                $filearea,

                                $step->get_id()

                            );

                }

                $attemptdata->steps[$stepno] = $stepdata;

            }

        }

        if (!empty($attemptdata->steps)) {

            writer::with_context($context)

                ->export_related_data($questionnocontext, 'steps', $attemptdata);

        }

    }

    /**

     * Get the list of contexts where the specified user has either created, or edited a question.

     *

     * To export usage of a question, please call {@link provider::export_question_usage()} from the module which

     * instantiated the usage of the question.

     *

     * @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): contextlist {

        $contextlist = new contextlist();

        // A user may have created or updated a question.

        // Questions are linked against a question category, which has a contextid field.

        $sql = "SELECT qc.contextid

                  FROM {question} q

                  JOIN {question_versions} qv ON qv.questionid = q.id

                  JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid

                  JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid

                 WHERE q.createdby = :useridcreated

                       OR q.modifiedby = :useridmodified";

        $params = [

            'useridcreated' => $userid,

            'useridmodified' => $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) {

        $context = $userlist->get_context();

        // A user may have created or updated a question.

        // Questions are linked against a question category, which has a contextid field.

        $sql = "SELECT q.createdby, q.modifiedby

                  FROM {question} q

                  JOIN {question_versions} qv ON qv.questionid = q.id

                  JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid

                  JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid

                 WHERE qc.contextid = :contextid";

        $params = [

            'contextid' => $context->id

        ];

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

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

    }

    /**

     * Determine related question usages for a user.

     *

     * @param   string          $prefix     A unique prefix to add to the table alias

     * @param   string          $component  The name of the component to fetch usages for.

     * @param   string          $joinfield  The SQL field name to use in the JOIN ON - e.g. q.usageid

     * @param   int             $userid     The user to search.

     * @return  \qubaid_join

     */

    public static function get_related_question_usages_for_user(string $prefix, string $component, string $joinfield, int $userid): \qubaid_join {

        return new \qubaid_join("

                JOIN {question_usages} {$prefix}_qu ON {$prefix}_qu.id = {$joinfield}

                 AND {$prefix}_qu.component = :{$prefix}_usagecomponent

                JOIN {question_attempts} {$prefix}_qa ON {$prefix}_qa.questionusageid = {$prefix}_qu.id

                JOIN {question_attempt_steps} {$prefix}_qas ON {$prefix}_qas.questionattemptid = {$prefix}_qa.id",

            "{$prefix}_qu.id",

            "{$prefix}_qas.userid = :{$prefix}_stepuserid",

            [

                "{$prefix}_stepuserid" => $userid,

                "{$prefix}_usagecomponent" => $component,

            ]);

    }

    /**

     * Add the list of users who have rated in the specified constraints.

     *

     * @param   userlist    $userlist   The userlist to add the users to.

     * @param   string      $prefix     A unique prefix to add to the table alias to avoid interference with your own sql.

     * @param   string      $insql      The SQL to use in a sub-select for the question_usages.id query.

     * @param   array       $params     The params required for the insql.

     * @param   int|null    $contextid  An optional context id, in case the $sql query is not already filtered by that.

     */

    public static function get_users_in_context_from_sql(userlist $userlist, string $prefix, string $insql, $params,

            int $contextid = null) {

        $sql = "SELECT {$prefix}_qas.userid

                  FROM {question_attempt_steps} {$prefix}_qas

                  JOIN {question_attempts} {$prefix}_qa ON {$prefix}_qas.questionattemptid = {$prefix}_qa.id

                  JOIN {question_usages} {$prefix}_qu ON {$prefix}_qa.questionusageid = {$prefix}_qu.id

                 WHERE {$prefix}_qu.id IN ({$insql})";

        if ($contextid) {

            $sql .= " AND {$prefix}_qu.contextid = :{$prefix}_contextid";

            $params["{$prefix}_contextid"] = $contextid;

        }

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

    }

    /**

     * 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 $CFG, $DB, $SITE;

        if (empty($contextlist)) {

            return;

        }

        // Use the Moodle XML Data format.

        // It is the only lossless format that we support.

        $format = "xml";

        require_once($CFG->dirroot . "/question/format/{$format}/format.php");

        // THe export system needs questions in a particular format.

        // The easiest way to fetch these is with get_questions_category() which takes the details of a question

        // category.

        // We fetch the root question category for each context and the get_questions_category function recurses to

        // After fetching them, we filter out any not created or modified by the requestor.

        $user = $contextlist->get_user();

        $userid = $user->id;

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

        $categories = $DB->get_records_select('question_categories', "contextid {$contextsql} AND parent = 0", $contextparams);

        $classname = "qformat_{$format}";

        foreach ($categories as $category) {

            $context = \context::instance_by_id($category->contextid);

            $questions = get_questions_category($category, true);

            $questions = array_filter($questions, function($question) use ($userid) {

                return ($question->createdby == $userid) || ($question->modifiedby == $userid);

            }, ARRAY_FILTER_USE_BOTH);

            if (empty($questions)) {

                continue;

            }

            $qformat = new $classname();

            $qformat->setQuestions($questions);

            $qformat->setContexts([$context]);

            $qformat->setContexttofile(true);

            // We do not know which course this belongs to, and it's not actually used except in error, so use Site.

            $qformat->setCourse($SITE);

            $content = '';

            if ($qformat->exportpreprocess()) {

                $content = $qformat->exportprocess(false);

            }

            $subcontext = [

                get_string('questionbank', 'core_question'),

            ];

            writer::with_context($context)->export_custom_file($subcontext, 'questions.xml', $content);

        }

    }

    /**

     * Delete all data for all users in the specified context.

     *

     * @param \context $context The specific context to delete data for.

     * @throws \dml_exception

     */

    public static function delete_data_for_all_users_in_context(\context $context) {

        global $DB;

        // Questions are considered to be 'owned' by the institution, even if they were originally written by a specific

        // user. They are still exported in the list of a users data, but they are not removed.

        // The userid is instead anonymised.

        $sql = 'SELECT q.*

                  FROM {question} q

                  JOIN {question_versions} qv ON qv.questionid = q.id

                  JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid

                  JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid

                 WHERE qc.contextid = ?';

        $questions = $DB->get_records_sql($sql, [$context->id]);

        foreach ($questions as $question) {

            $question->createdby = 0;

            $question->modifiedby = 0;

            $DB->update_record('question', $question);

        }

    }

    /**

     * 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;

        // Questions are considered to be 'owned' by the institution, even if they were originally written by a specific

        // user. They are still exported in the list of a users data, but they are not removed.

        // The userid is instead anonymised.

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

        $contextparams['createdby'] = $contextlist->get_user()->id;

        $questiondata = $DB->get_records_sql(

            "SELECT q.*

               FROM {question} q

               JOIN {question_versions} qv ON qv.questionid = q.id

               JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid

               JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid

              WHERE qc.contextid {$contextsql}

                    AND q.createdby = :createdby", $contextparams);

        foreach ($questiondata as $question) {

            $question->createdby = 0;

            $DB->update_record('question', $question);

        }

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

        $contextparams['modifiedby'] = $contextlist->get_user()->id;

        $questiondata = $DB->get_records_sql(

            "SELECT q.*

               FROM {question} q

               JOIN {question_versions} qv ON qv.questionid = q.id

               JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid

               JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid

              WHERE qc.contextid {$contextsql}

                    AND q.modifiedby = :modifiedby", $contextparams);

        foreach ($questiondata as $question) {

            $question->modifiedby = 0;

            $DB->update_record('question', $question);

        }

    }

    /**

     * Delete multiple users within a single context.

     *

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

     */

    public static function delete_data_for_users(approved_userlist $userlist) {

        global $DB;

        // Questions are considered to be 'owned' by the institution, even if they were originally written by a specific

        // user. They are still exported in the list of a users data, but they are not removed.

        // The userid is instead anonymised.

        $context = $userlist->get_context();

        $userids = $userlist->get_userids();

        list($createdbysql, $createdbyparams) = $DB->get_in_or_equal($userids, SQL_PARAMS_NAMED);

        list($modifiedbysql, $modifiedbyparams) = $DB->get_in_or_equal($userids, SQL_PARAMS_NAMED);

        $params = ['contextid' => $context->id];

        $questiondata = $DB->get_records_sql(

            "SELECT q.*

               FROM {question} q

               JOIN {question_versions} qv ON qv.questionid = q.id

               JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid

               JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid

              WHERE qc.contextid = :contextid

                    AND q.createdby {$createdbysql}", $params + $createdbyparams);

        foreach ($questiondata as $question) {

            $question->createdby = 0;

            $DB->update_record('question', $question);

        }

        $questiondata = $DB->get_records_sql(

            "SELECT q.*

               FROM {question} q

               JOIN {question_versions} qv ON qv.questionid = q.id

               JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid

               JOIN {question_categories} qc ON qc.id = qbe.questioncategoryid

              WHERE qc.contextid = :contextid

                    AND q.modifiedby {$modifiedbysql}", $params + $modifiedbyparams);

        foreach ($questiondata as $question) {

            $question->modifiedby = 0;

            $DB->update_record('question', $question);

        }

    }

}