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See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?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/>.

/**
 * More object oriented wrappers around parts of the Moodle question bank.
 *
 * In due course, I expect that the question bank will be converted to a
 * fully object oriented structure, at which point this file can be a
 * starting point.
 *
 * @package    moodlecore
 * @subpackage questionbank
 * @copyright  2009 The Open University
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */


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

require_once(__DIR__ . '/../type/questiontypebase.php');


/**
 * This static class provides access to the other question bank.
 *
 * It provides functions for managing question types and question definitions.
 *
 * @copyright  2009 The Open University
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
abstract class question_bank {
    // TODO: This limit can be deleted if someday we move all TEXTS to BIG ones. MDL-19603
    const MAX_SUMMARY_LENGTH = 32000;

    /** @var array question type name => question_type subclass. */
    private static $questiontypes = array();

    /** @var array question type name => 1. Records which question definitions have been loaded. */
    private static $loadedqdefs = array();

    /** @var boolean nasty hack to allow unit tests to call {@link load_question()}. */
    private static $testmode = false;
    private static $testdata = array();

    private static $questionconfig = null;

    /**
     * @var array string => string The standard set of grade options (fractions)
     * to use when editing questions, in the range 0 to 1 inclusive. Array keys
     * are string becuase: a) we want grades to exactly 7 d.p., and b. you can't
     * have float array keys in PHP.
     * Initialised by {@link ensure_grade_options_initialised()}.
     */
    private static $fractionoptions = null;
    /** @var array string => string The full standard set of (fractions) -1 to 1 inclusive. */
    private static $fractionoptionsfull = null;

    /**
     * @param string $qtypename a question type name, e.g. 'multichoice'.
     * @return bool whether that question type is installed in this Moodle.
     */
    public static function is_qtype_installed($qtypename) {
        $plugindir = core_component::get_plugin_directory('qtype', $qtypename);
        return $plugindir && is_readable($plugindir . '/questiontype.php');
    }

    /**
     * Get the question type class for a particular question type.
     * @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'.
     * @param bool $mustexist if false, the missing question type is returned when
     *      the requested question type is not installed.
     * @return question_type the corresponding question type class.
     */
    public static function get_qtype($qtypename, $mustexist = true) {
        global $CFG;
        if (isset(self::$questiontypes[$qtypename])) {
            return self::$questiontypes[$qtypename];
        }
        $file = core_component::get_plugin_directory('qtype', $qtypename) . '/questiontype.php';
        if (!is_readable($file)) {
            if ($mustexist || $qtypename == 'missingtype') {
                throw new coding_exception('Unknown question type ' . $qtypename);
            } else {
                return self::get_qtype('missingtype');
            }
        }
        include_once($file);
        $class = 'qtype_' . $qtypename;
        if (!class_exists($class)) {
            throw new coding_exception("Class {$class} must be defined in {$file}.");
        }
        self::$questiontypes[$qtypename] = new $class();
        return self::$questiontypes[$qtypename];
    }

    /**
     * Load the question configuration data from config_plugins.
     * @return object get_config('question') with caching.
     */
    public static function get_config() {
        if (is_null(self::$questionconfig)) {
            self::$questionconfig = get_config('question');
        }
        return self::$questionconfig;
    }

    /**
     * @param string $qtypename the internal name of a question type. For example multichoice.
     * @return bool whether users are allowed to create questions of this type.
     */
    public static function qtype_enabled($qtypename) {
        $config = self::get_config();
        $enabledvar = $qtypename . '_disabled';
        return self::qtype_exists($qtypename) && empty($config->$enabledvar) &&
                self::get_qtype($qtypename)->menu_name() != '';
    }

    /**
     * @param string $qtypename the internal name of a question type. For example multichoice.
     * @return bool whether this question type exists.
     */
    public static function qtype_exists($qtypename) {
        return array_key_exists($qtypename, core_component::get_plugin_list('qtype'));
    }

    /**
     * @param $qtypename the internal name of a question type, for example multichoice.
     * @return string the human_readable name of this question type, from the language pack.
     */
    public static function get_qtype_name($qtypename) {
        return self::get_qtype($qtypename)->local_name();
    }

    /**
     * @return array all the installed question types.
     */
    public static function get_all_qtypes() {
        $qtypes = array();
        foreach (core_component::get_plugin_list('qtype') as $plugin => $notused) {
            try {
                $qtypes[$plugin] = self::get_qtype($plugin);
            } catch (coding_exception $e) {
                // Catching coding_exceptions here means that incompatible
                // question types do not cause the rest of Moodle to break.
            }
        }
        return $qtypes;
    }

    /**
     * Sort an array of question types according to the order the admin set up,
     * and then alphabetically for the rest.
     * @param array qtype->name() => qtype->local_name().
     * @return array sorted array.
     */
    public static function sort_qtype_array($qtypes, $config = null) {
        if (is_null($config)) {
            $config = self::get_config();
        }

        $sortorder = array();
        $otherqtypes = array();
        foreach ($qtypes as $name => $localname) {
            $sortvar = $name . '_sortorder';
            if (isset($config->$sortvar)) {
                $sortorder[$config->$sortvar] = $name;
            } else {
                $otherqtypes[$name] = $localname;
            }
        }

        ksort($sortorder);
        core_collator::asort($otherqtypes);

        $sortedqtypes = array();
        foreach ($sortorder as $name) {
            $sortedqtypes[$name] = $qtypes[$name];
        }
        foreach ($otherqtypes as $name => $notused) {
            $sortedqtypes[$name] = $qtypes[$name];
        }
        return $sortedqtypes;
    }

    /**
     * @return array all the question types that users are allowed to create,
     *      sorted into the preferred order set on the admin screen.
     */
    public static function get_creatable_qtypes() {
        $config = self::get_config();
        $allqtypes = self::get_all_qtypes();

        $qtypenames = array();
        foreach ($allqtypes as $name => $qtype) {
            if (self::qtype_enabled($name)) {
                $qtypenames[$name] = $qtype->local_name();
            }
        }

        $qtypenames = self::sort_qtype_array($qtypenames);

        $creatableqtypes = array();
        foreach ($qtypenames as $name => $notused) {
            $creatableqtypes[$name] = $allqtypes[$name];
        }
        return $creatableqtypes;
    }

    /**
     * Load the question definition class(es) belonging to a question type. That is,
     * include_once('/question/type/' . $qtypename . '/question.php'), with a bit
     * of checking.
     * @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'.
     */
    public static function load_question_definition_classes($qtypename) {
        global $CFG;
        if (isset(self::$loadedqdefs[$qtypename])) {
            return;
        }
        $file = $CFG->dirroot . '/question/type/' . $qtypename . '/question.php';
        if (!is_readable($file)) {
            throw new coding_exception('Unknown question type (no definition) ' . $qtypename);
        }
        include_once($file);
        self::$loadedqdefs[$qtypename] = 1;
    }

    /**
     * This method needs to be called whenever a question is edited.
     */
    public static function notify_question_edited($questionid) {
        question_finder::get_instance()->uncache_question($questionid);
    }

    /**
     * Load a question definition data from the database. The data will be
     * returned as a plain stdClass object.
     * @param int $questionid the id of the question to load.
     * @return object question definition loaded from the database.
     */
    public static function load_question_data($questionid) {
        return question_finder::get_instance()->load_question_data($questionid);
    }

    /**
     * Load a question definition from the database. The object returned
     * will actually be of an appropriate {@link question_definition} subclass.
     * @param int $questionid the id of the question to load.
     * @param bool $allowshuffle if false, then any shuffle option on the selected
     *      quetsion is disabled.
     * @return question_definition loaded from the database.
     */
    public static function load_question($questionid, $allowshuffle = true) {

        if (self::$testmode) {
            // Evil, test code in production, but no way round it.
            return self::return_test_question_data($questionid);
        }

        $questiondata = self::load_question_data($questionid);

        if (!$allowshuffle) {
            $questiondata->options->shuffleanswers = false;
        }
        return self::make_question($questiondata);
    }

    /**
     * Convert the question information loaded with {@link get_question_options()}
     * to a question_definintion object.
     * @param object $questiondata raw data loaded from the database.
     * @return question_definition loaded from the database.
     */
    public static function make_question($questiondata) {
        return self::get_qtype($questiondata->qtype, false)->make_question($questiondata, false);
    }

    /**
> * Get all the versions of a particular question. * @return question_finder a question finder. > * */ > * @param int $questionid id of the question public static function get_finder() { > * @return array The array keys are version number, and the values are objects with three int fields return question_finder::get_instance(); > * version (same as array key), versionid and questionid. } > */ > public static function get_all_versions_of_question(int $questionid): array { /** > global $DB; * Only to be called from unit tests. Allows {@link load_test_data()} to be used. > $sql = "SELECT qv.id AS versionid, qv.version, qv.questionid */ > FROM {question_versions} qv public static function start_unit_test() { > WHERE qv.questionbankentryid = (SELECT DISTINCT qbe.id self::$testmode = true; > FROM {question_bank_entries} qbe } > JOIN {question_versions} qv ON qbe.id = qv.questionbankentryid > JOIN {question} q ON qv.questionid = q.id /** > WHERE q.id = ?) * Only to be called from unit tests. Allows {@link load_test_data()} to be used. > ORDER BY qv.version DESC"; */ > public static function end_unit_test() { > return $DB->get_records_sql($sql, [$questionid]); self::$testmode = false; > } self::$testdata = array(); > } > /** > * Get all the versions of questions. private static function return_test_question_data($questionid) { > * if (!isset(self::$testdata[$questionid])) { > * @param array $questionids Array of question ids. throw new coding_exception('question_bank::return_test_data(' . $questionid . > * @return array two dimensional array question_bank_entries.id => version number => question.id. ') called, but no matching question has been loaded by load_test_data.'); > * Versions in descending order. } > */ return self::$testdata[$questionid]; > public static function get_all_versions_of_questions(array $questionids): array { } > global $DB; > /** > [$listquestionid, $params] = $DB->get_in_or_equal($questionids, SQL_PARAMS_NAMED); * To be used for unit testing only. Will throw an exception if > $sql = "SELECT qv.questionid, qv.version, qv.questionbankentryid * {@link start_unit_test()} has not been called first. > FROM {question_versions} qv * @param object $questiondata a question data object to put in the test data store. > JOIN {question_versions} qv2 ON qv.questionbankentryid = qv2.questionbankentryid */ > WHERE qv2.questionid $listquestionid public static function load_test_question_data(question_definition $question) { > ORDER BY qv.questionbankentryid, qv.version DESC"; if (!self::$testmode) { > $result = []; throw new coding_exception('question_bank::load_test_data called when ' . > $rows = $DB->get_recordset_sql($sql, $params); 'not in test mode.'); > foreach ($rows as $row) { } > $result[$row->questionbankentryid][$row->version] = $row->questionid; self::$testdata[$question->id] = $question; > } } > > return $result; protected static function ensure_fraction_options_initialised() { > } if (!is_null(self::$fractionoptions)) { > return; > /**
} // define basic array of grades. This list comprises all fractions of the form: // a. p/q for q <= 6, 0 <= p <= q // b. p/10 for 0 <= p <= 10 // c. 1/q for 1 <= q <= 10 // d. 1/20 $rawfractions = array( 0.9000000, 0.8333333, 0.8000000, 0.7500000, 0.7000000, 0.6666667, 0.6000000, 0.5000000, 0.4000000, 0.3333333, 0.3000000, 0.2500000, 0.2000000, 0.1666667, 0.1428571, 0.1250000, 0.1111111, 0.1000000, 0.0500000, ); // Put the None option at the top. self::$fractionoptions = array( '0.0' => get_string('none'), '1.0' => '100%', ); self::$fractionoptionsfull = array( '0.0' => get_string('none'), '1.0' => '100%', ); // The the positive grades in descending order. foreach ($rawfractions as $fraction) { $percentage = format_float(100 * $fraction, 5, true, true) . '%'; self::$fractionoptions["{$fraction}"] = $percentage; self::$fractionoptionsfull["{$fraction}"] = $percentage; } // The the negative grades in descending order. foreach (array_reverse($rawfractions) as $fraction) { self::$fractionoptionsfull['' . (-$fraction)] = format_float(-100 * $fraction, 5, true, true) . '%'; } self::$fractionoptionsfull['-1.0'] = '-100%'; } /** * @return array string => string The standard set of grade options (fractions) * to use when editing questions, in the range 0 to 1 inclusive. Array keys * are string becuase: a) we want grades to exactly 7 d.p., and b. you can't * have float array keys in PHP. * Initialised by {@link ensure_grade_options_initialised()}. */ public static function fraction_options() { self::ensure_fraction_options_initialised(); return self::$fractionoptions; } /** @return array string => string The full standard set of (fractions) -1 to 1 inclusive. */ public static function fraction_options_full() { self::ensure_fraction_options_initialised(); return self::$fractionoptionsfull; } /** * Return a list of the different question types present in the given categories. * * @param array $categories a list of category ids * @return array the list of question types in the categories * @since Moodle 3.1 */ public static function get_all_question_types_in_categories($categories) { global $DB; list($categorysql, $params) = $DB->get_in_or_equal($categories); $sql = "SELECT DISTINCT q.qtype FROM {question} q JOIN {question_versions} qv ON qv.questionid = q.id JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid WHERE qbe.questioncategoryid $categorysql"; $qtypes = $DB->get_fieldset_sql($sql, $params); return $qtypes; } } /** * Class for loading questions according to various criteria. * * @copyright 2009 The Open University * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ class question_finder implements cache_data_source { /** @var question_finder the singleton instance of this class. */ protected static $questionfinder = null; /** * @return question_finder a question finder. */ public static function get_instance() { if (is_null(self::$questionfinder)) { self::$questionfinder = new question_finder(); } return self::$questionfinder; } /* See cache_data_source::get_instance_for_cache. */ public static function get_instance_for_cache(cache_definition $definition) { return self::get_instance(); } /** * @return cache_application the question definition cache we are using. */ protected function get_data_cache() { // Do not double cache here because it may break cache resetting. return cache::make('core', 'questiondata'); } /** * This method needs to be called whenever a question is edited. */ public function uncache_question($questionid) { $this->get_data_cache()->delete($questionid); } /** * Load a question definition data from the database. The data will be * returned as a plain stdClass object. * @param int $questionid the id of the question to load. * @return object question definition loaded from the database. */ public function load_question_data($questionid) { return $this->get_data_cache()->get($questionid); } /** * Get the ids of all the questions in a list of categories. * @param array $categoryids either a categoryid, or a comma-separated list
< * category ids, or an array of them.
> * of category ids, or an array of them.
* @param string $extraconditions extra conditions to AND with the rest of * the where clause. Must use named parameters. * @param array $extraparams any parameters used by $extraconditions. * @return array questionid => questionid. */ public function get_questions_from_categories($categoryids, $extraconditions, $extraparams = array()) { global $DB; list($qcsql, $qcparams) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED, 'qc'); if ($extraconditions) { $extraconditions = ' AND (' . $extraconditions . ')'; } $qcparams['readystatus'] = \core_question\local\bank\question_version_status::QUESTION_STATUS_READY;
> $qcparams['readystatusqv'] = \core_question\local\bank\question_version_status::QUESTION_STATUS_READY;
$sql = "SELECT q.id, q.id AS id2 FROM {question} q JOIN {question_versions} qv ON qv.questionid = q.id JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid WHERE qbe.questioncategoryid {$qcsql} AND q.parent = 0 AND qv.status = :readystatus
> AND qv.version = (SELECT MAX(v.version) {$extraconditions}"; > FROM {question_versions} v > JOIN {question_bank_entries} be return $DB->get_records_sql_menu($sql, $qcparams + $extraparams); > ON be.id = v.questionbankentryid } > WHERE be.id = qbe.id > AND v.status = :readystatusqv)
/** * Get the ids of all the questions in a list of categories, with the number * of times they have already been used in a given set of usages. * * The result array is returned in order of increasing (count previous uses). * * @param array $categoryids an array question_category ids. * @param qubaid_condition $qubaids which question_usages to count previous uses from. * @param string $extraconditions extra conditions to AND with the rest of * the where clause. Must use named parameters. * @param array $extraparams any parameters used by $extraconditions. * @return array questionid => count of number of previous uses. */ public function get_questions_from_categories_with_usage_counts($categoryids, qubaid_condition $qubaids, $extraconditions = '', $extraparams = array()) { return $this->get_questions_from_categories_and_tags_with_usage_counts( $categoryids, $qubaids, $extraconditions, $extraparams); } /** * Get the ids of all the questions in a list of categories that have ALL the provided tags, * with the number of times they have already been used in a given set of usages. * * The result array is returned in order of increasing (count previous uses). * * @param array $categoryids an array of question_category ids. * @param qubaid_condition $qubaids which question_usages to count previous uses from. * @param string $extraconditions extra conditions to AND with the rest of * the where clause. Must use named parameters. * @param array $extraparams any parameters used by $extraconditions. * @param array $tagids an array of tag ids * @return array questionid => count of number of previous uses. */ public function get_questions_from_categories_and_tags_with_usage_counts($categoryids, qubaid_condition $qubaids, $extraconditions = '', $extraparams = array(), $tagids = array()) { global $DB; list($qcsql, $qcparams) = $DB->get_in_or_equal($categoryids, SQL_PARAMS_NAMED, 'qc'); $readystatus = \core_question\local\bank\question_version_status::QUESTION_STATUS_READY; $select = "q.id, (SELECT COUNT(1) FROM " . $qubaids->from_question_attempts('qa') . " WHERE qa.questionid = q.id AND " . $qubaids->where() . " ) AS previous_attempts"; $from = "{question} q"; $join = "JOIN {question_versions} qv ON qv.questionid = q.id JOIN {question_bank_entries} qbe ON qbe.id = qv.questionbankentryid"; $from = $from . " " . $join; $where = "qbe.questioncategoryid {$qcsql} AND q.parent = 0 AND qv.status = '$readystatus' AND qv.version = (SELECT MAX(v.version) FROM {question_versions} v JOIN {question_bank_entries} be ON be.id = v.questionbankentryid WHERE be.id = qbe.id)"; $params = $qcparams; if (!empty($tagids)) { // We treat each additional tag as an AND condition rather than // an OR condition. // // For example, if the user filters by the tags "foo" and "bar" then // we reduce the question list to questions that are tagged with both // "foo" AND "bar". Any question that does not have ALL of the specified // tags will be omitted. list($tagsql, $tagparams) = $DB->get_in_or_equal($tagids, SQL_PARAMS_NAMED, 'ti'); $tagparams['tagcount'] = count($tagids); $tagparams['questionitemtype'] = 'question'; $tagparams['questioncomponent'] = 'core_question'; $where .= " AND q.id IN (SELECT ti.itemid FROM {tag_instance} ti WHERE ti.itemtype = :questionitemtype AND ti.component = :questioncomponent AND ti.tagid {$tagsql} GROUP BY ti.itemid HAVING COUNT(itemid) = :tagcount)"; $params += $tagparams; } if ($extraconditions) { $extraconditions = ' AND (' . $extraconditions . ')'; } return $DB->get_records_sql_menu("SELECT $select FROM $from WHERE $where $extraconditions ORDER BY previous_attempts", $qubaids->from_where_params() + $params + $extraparams); } /* See cache_data_source::load_for_cache. */ public function load_for_cache($questionid) { global $DB; $sql = 'SELECT q.id, qc.id as category, q.parent, q.name, q.questiontext, q.questiontextformat, q.generalfeedback, q.generalfeedbackformat, q.defaultmark, q.penalty, q.qtype, q.length, q.stamp, q.timecreated, q.timemodified, q.createdby, q.modifiedby, qbe.idnumber, qc.contextid, qv.status, qv.id as versionid, qv.version, qv.questionbankentryid 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.id = :id'; $questiondata = $DB->get_record_sql($sql, ['id' => $questionid], MUST_EXIST); get_question_options($questiondata); return $questiondata; } /* See cache_data_source::load_many_for_cache. */ public function load_many_for_cache(array $questionids) { global $DB; list($idcondition, $params) = $DB->get_in_or_equal($questionids); $sql = 'SELECT q.id, qc.id as category, q.parent, q.name, q.questiontext, q.questiontextformat, q.generalfeedback, q.generalfeedbackformat, q.defaultmark, q.penalty, q.qtype, q.length, q.stamp, q.timecreated, q.timemodified, q.createdby, q.modifiedby, qbe.idnumber, qc.contextid, qv.status, qv.id as versionid, qv.version, qv.questionbankentryid 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.id '; $questiondata = $DB->get_records_sql($sql . $idcondition, $params); foreach ($questionids as $id) { if (!array_key_exists($id, $questiondata)) { throw new dml_missing_record_exception('question', '', ['id' => $id]); } get_question_options($questiondata[$id]); } return $questiondata; } }