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Developer Documentation
- 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.
/question/engine/ -> lib.php (source)
<?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/>.
/**
* This defines the core classes of the Moodle question engine.
*
* @package moodlecore
* @subpackage questionengine
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
require_once($CFG->libdir . '/filelib.php');
require_once(__DIR__ . '/questionusage.php');
require_once(__DIR__ . '/questionattempt.php');
require_once(__DIR__ . '/questionattemptstep.php');
require_once(__DIR__ . '/states.php');
require_once(__DIR__ . '/datalib.php');
require_once(__DIR__ . '/renderer.php');
require_once(__DIR__ . '/bank.php');
require_once(__DIR__ . '/../type/questiontypebase.php');
require_once(__DIR__ . '/../type/questionbase.php');
require_once(__DIR__ . '/../type/rendererbase.php');
require_once(__DIR__ . '/../behaviour/behaviourtypebase.php');
require_once(__DIR__ . '/../behaviour/behaviourbase.php');
require_once(__DIR__ . '/../behaviour/rendererbase.php');
require_once($CFG->libdir . '/questionlib.php');
/**
* This static class provides access to the other question engine classes.
*
* It provides functions for managing question behaviours), and for
* creating, loading, saving and deleting {@link question_usage_by_activity}s,
* which is the main class that is used by other code that wants to use questions.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class question_engine {
/** @var array behaviour name => 1. Records which behaviours have been loaded. */
private static $loadedbehaviours = array();
/** @var array behaviour name => question_behaviour_type for this behaviour. */
private static $behaviourtypes = array();
/**
* Create a new {@link question_usage_by_activity}. The usage is
* created in memory. If you want it to persist, you will need to call
* {@link save_questions_usage_by_activity()}.
*
* @param string $component the plugin creating this attempt. For example mod_quiz.
* @param context $context the context this usage belongs to.
* @return question_usage_by_activity the newly created object.
*/
public static function make_questions_usage_by_activity($component, $context) {
return new question_usage_by_activity($component, $context);
}
/**
* Load a {@link question_usage_by_activity} from the database, based on its id.
* @param int $qubaid the id of the usage to load.
* @param moodle_database $db a database connectoin. Defaults to global $DB.
* @return question_usage_by_activity loaded from the database.
*/
public static function load_questions_usage_by_activity($qubaid, moodle_database $db = null) {
$dm = new question_engine_data_mapper($db);
return $dm->load_questions_usage_by_activity($qubaid);
}
/**
* Save a {@link question_usage_by_activity} to the database. This works either
* if the usage was newly created by {@link make_questions_usage_by_activity()}
* or loaded from the database using {@link load_questions_usage_by_activity()}
* @param question_usage_by_activity the usage to save.
* @param moodle_database $db a database connectoin. Defaults to global $DB.
*/
public static function save_questions_usage_by_activity(question_usage_by_activity $quba, moodle_database $db = null) {
$dm = new question_engine_data_mapper($db);
$observer = $quba->get_observer();
if ($observer instanceof question_engine_unit_of_work) {
$observer->save($dm);
} else {
$dm->insert_questions_usage_by_activity($quba);
}
}
/**
* Delete a {@link question_usage_by_activity} from the database, based on its id.
* @param int $qubaid the id of the usage to delete.
*/
public static function delete_questions_usage_by_activity($qubaid) {
self::delete_questions_usage_by_activities(new qubaid_list(array($qubaid)));
}
/**
* Delete {@link question_usage_by_activity}s from the database.
* @param qubaid_condition $qubaids identifies which questions usages to delete.
*/
public static function delete_questions_usage_by_activities(qubaid_condition $qubaids) {
$dm = new question_engine_data_mapper();
$dm->delete_questions_usage_by_activities($qubaids);
}
/**
* Change the maxmark for the question_attempt with number in usage $slot
* for all the specified question_attempts.
* @param qubaid_condition $qubaids Selects which usages are updated.
* @param int $slot the number is usage to affect.
* @param number $newmaxmark the new max mark to set.
*/
public static function set_max_mark_in_attempts(qubaid_condition $qubaids,
$slot, $newmaxmark) {
$dm = new question_engine_data_mapper();
$dm->set_max_mark_in_attempts($qubaids, $slot, $newmaxmark);
}
/**
* Validate that the manual grade submitted for a particular question is in range.
* @param int $qubaid the question_usage id.
* @param int $slot the slot number within the usage.
* @return bool whether the submitted data is in range.
*/
public static function is_manual_grade_in_range($qubaid, $slot) {
$prefix = 'q' . $qubaid . ':' . $slot . '_';
$mark = question_utils::optional_param_mark($prefix . '-mark');
$maxmark = optional_param($prefix . '-maxmark', null, PARAM_FLOAT);
$minfraction = optional_param($prefix . ':minfraction', null, PARAM_FLOAT);
$maxfraction = optional_param($prefix . ':maxfraction', null, PARAM_FLOAT);
return $mark === '' ||
($mark !== null && $mark >= $minfraction * $maxmark && $mark <= $maxfraction * $maxmark) ||
($mark === null && $maxmark === null);
}
/**
* @param array $questionids of question ids.
* @param qubaid_condition $qubaids ids of the usages to consider.
* @return boolean whether any of these questions are being used by any of
* those usages.
*/
public static function questions_in_use(array $questionids, qubaid_condition $qubaids = null) {
if (is_null($qubaids)) {
return false;
}
$dm = new question_engine_data_mapper();
return $dm->questions_in_use($questionids, $qubaids);
}
/**
* Get the number of times each variant has been used for each question in a list
* in a set of usages.
* @param array $questionids of question ids.
* @param qubaid_condition $qubaids ids of the usages to consider.
* @return array questionid => variant number => num uses.
*/
public static function load_used_variants(array $questionids, qubaid_condition $qubaids) {
$dm = new question_engine_data_mapper();
return $dm->load_used_variants($questionids, $qubaids);
}
/**
* Create an archetypal behaviour for a particular question attempt.
* Used by {@link question_definition::make_behaviour()}.
*
* @param string $preferredbehaviour the type of model required.
* @param question_attempt $qa the question attempt the model will process.
* @return question_behaviour an instance of appropriate behaviour class.
*/
public static function make_archetypal_behaviour($preferredbehaviour, question_attempt $qa) {
if (!self::is_behaviour_archetypal($preferredbehaviour)) {
throw new coding_exception('The requested behaviour is not actually ' .
'an archetypal one.');
}
self::load_behaviour_class($preferredbehaviour);
$class = 'qbehaviour_' . $preferredbehaviour;
return new $class($qa, $preferredbehaviour);
}
/**
* @param string $behaviour the name of a behaviour.
* @return array of {@link question_display_options} field names, that are
* not relevant to this behaviour before a 'finish' action.
*/
public static function get_behaviour_unused_display_options($behaviour) {
return self::get_behaviour_type($behaviour)->get_unused_display_options();
}
/**
* With this behaviour, is it possible that a question might finish as the student
* interacts with it, without a call to the {@link question_attempt::finish()} method?
* @param string $behaviour the name of a behaviour. E.g. 'deferredfeedback'.
* @return bool whether with this behaviour, questions may finish naturally.
*/
public static function can_questions_finish_during_the_attempt($behaviour) {
return self::get_behaviour_type($behaviour)->can_questions_finish_during_the_attempt();
}
/**
* Create a behaviour for a particular type. If that type cannot be
* found, return an instance of qbehaviour_missing.
*
* Normally you should use {@link make_archetypal_behaviour()}, or
* call the constructor of a particular model class directly. This method
* is only intended for use by {@link question_attempt::load_from_records()}.
*
* @param string $behaviour the type of model to create.
* @param question_attempt $qa the question attempt the model will process.
* @param string $preferredbehaviour the preferred behaviour for the containing usage.
* @return question_behaviour an instance of appropriate behaviour class.
*/
public static function make_behaviour($behaviour, question_attempt $qa, $preferredbehaviour) {
try {
self::load_behaviour_class($behaviour);
} catch (Exception $e) {
self::load_behaviour_class('missing');
return new qbehaviour_missing($qa, $preferredbehaviour);
}
$class = 'qbehaviour_' . $behaviour;
return new $class($qa, $preferredbehaviour);
}
/**
* Load the behaviour class(es) belonging to a particular model. That is,
* include_once('/question/behaviour/' . $behaviour . '/behaviour.php'), with a bit
* of checking.
* @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'.
*/
public static function load_behaviour_class($behaviour) {
global $CFG;
if (isset(self::$loadedbehaviours[$behaviour])) {
return;
}
$file = $CFG->dirroot . '/question/behaviour/' . $behaviour . '/behaviour.php';
if (!is_readable($file)) {
throw new coding_exception('Unknown question behaviour ' . $behaviour);
}
include_once($file);
$class = 'qbehaviour_' . $behaviour;
if (!class_exists($class)) {
throw new coding_exception('Question behaviour ' . $behaviour .
' does not define the required class ' . $class . '.');
}
self::$loadedbehaviours[$behaviour] = 1;
}
/**
* Create a behaviour for a particular type. If that type cannot be
* found, return an instance of qbehaviour_missing.
*
* Normally you should use {@link make_archetypal_behaviour()}, or
* call the constructor of a particular model class directly. This method
* is only intended for use by {@link question_attempt::load_from_records()}.
*
* @param string $behaviour the type of model to create.
* @param question_attempt $qa the question attempt the model will process.
* @param string $preferredbehaviour the preferred behaviour for the containing usage.
* @return question_behaviour_type an instance of appropriate behaviour class.
*/
public static function get_behaviour_type($behaviour) {
if (array_key_exists($behaviour, self::$behaviourtypes)) {
return self::$behaviourtypes[$behaviour];
}
self::load_behaviour_type_class($behaviour);
$class = 'qbehaviour_' . $behaviour . '_type';
if (class_exists($class)) {
self::$behaviourtypes[$behaviour] = new $class();
} else {
debugging('Question behaviour ' . $behaviour .
' does not define the required class ' . $class . '.', DEBUG_DEVELOPER);
self::$behaviourtypes[$behaviour] = new question_behaviour_type_fallback($behaviour);
}
return self::$behaviourtypes[$behaviour];
}
/**
* Load the behaviour type class for a particular behaviour. That is,
* include_once('/question/behaviour/' . $behaviour . '/behaviourtype.php').
* @param string $behaviour the behaviour name. For example 'interactive' or 'deferredfeedback'.
*/
protected static function load_behaviour_type_class($behaviour) {
global $CFG;
if (isset(self::$behaviourtypes[$behaviour])) {
return;
}
$file = $CFG->dirroot . '/question/behaviour/' . $behaviour . '/behaviourtype.php';
if (!is_readable($file)) {
debugging('Question behaviour ' . $behaviour .
' is missing the behaviourtype.php file.', DEBUG_DEVELOPER);
}
include_once($file);
}
/**
* Return an array where the keys are the internal names of the archetypal
* behaviours, and the values are a human-readable name. An
* archetypal behaviour is one that is suitable to pass the name of to
* {@link question_usage_by_activity::set_preferred_behaviour()}.
*
* @return array model name => lang string for this behaviour name.
*/
public static function get_archetypal_behaviours() {
$archetypes = array();
$behaviours = core_component::get_plugin_list('qbehaviour');
foreach ($behaviours as $behaviour => $notused) {
if (self::is_behaviour_archetypal($behaviour)) {
$archetypes[$behaviour] = self::get_behaviour_name($behaviour);
}
}
asort($archetypes, SORT_LOCALE_STRING);
return $archetypes;
}
/**
* @param string $behaviour the name of a behaviour. E.g. 'deferredfeedback'.
* @return bool whether this is an archetypal behaviour.
*/
public static function is_behaviour_archetypal($behaviour) {
return self::get_behaviour_type($behaviour)->is_archetypal();
}
/**
* Return an array where the keys are the internal names of the behaviours
* in preferred order and the values are a human-readable name.
*
* @param array $archetypes, array of behaviours
* @param string $orderlist, a comma separated list of behaviour names
* @param string $disabledlist, a comma separated list of behaviour names
* @param string $current, current behaviour name
* @return array model name => lang string for this behaviour name.
*/
public static function sort_behaviours($archetypes, $orderlist, $disabledlist, $current=null) {
// Get disabled behaviours
if ($disabledlist) {
$disabled = explode(',', $disabledlist);
} else {
$disabled = array();
}
if ($orderlist) {
$order = explode(',', $orderlist);
} else {
$order = array();
}
foreach ($disabled as $behaviour) {
if (array_key_exists($behaviour, $archetypes) && $behaviour != $current) {
unset($archetypes[$behaviour]);
}
}
// Get behaviours in preferred order
$behaviourorder = array();
foreach ($order as $behaviour) {
if (array_key_exists($behaviour, $archetypes)) {
$behaviourorder[$behaviour] = $archetypes[$behaviour];
}
}
// Get the rest of behaviours and sort them alphabetically
$leftover = array_diff_key($archetypes, $behaviourorder);
asort($leftover, SORT_LOCALE_STRING);
// Set up the final order to be displayed
return $behaviourorder + $leftover;
}
/**
* Return an array where the keys are the internal names of the behaviours
* in preferred order and the values are a human-readable name.
*
* @param string $currentbehaviour
* @return array model name => lang string for this behaviour name.
*/
public static function get_behaviour_options($currentbehaviour) {
$config = question_bank::get_config();
$archetypes = self::get_archetypal_behaviours();
// If no admin setting return all behavious
if (empty($config->disabledbehaviours) && empty($config->behavioursortorder)) {
return $archetypes;
}
if (empty($config->behavioursortorder)) {
$order = '';
} else {
$order = $config->behavioursortorder;
}
if (empty($config->disabledbehaviours)) {
$disabled = '';
} else {
$disabled = $config->disabledbehaviours;
}
return self::sort_behaviours($archetypes, $order, $disabled, $currentbehaviour);
}
/**
* Get the translated name of a behaviour, for display in the UI.
* @param string $behaviour the internal name of the model.
* @return string name from the current language pack.
*/
public static function get_behaviour_name($behaviour) {
return get_string('pluginname', 'qbehaviour_' . $behaviour);
}
/**
* @return array all the file area names that may contain response files.
*/
public static function get_all_response_file_areas() {
$variables = array();
foreach (question_bank::get_all_qtypes() as $qtype) {
$variables = array_merge($variables, $qtype->response_file_areas());
}
$areas = array();
foreach (array_unique($variables) as $variable) {
$areas[] = 'response_' . $variable;
}
return $areas;
}
/**
* Returns the valid choices for the number of decimal places for showing
* question marks. For use in the user interface.
* @return array suitable for passing to {@link html_writer::select()} or similar.
*/
public static function get_dp_options() {
return question_display_options::get_dp_options();
}
/**
* Initialise the JavaScript required on pages where questions will be displayed.
*
* @return string
*/
public static function initialise_js() {
return question_flags::initialise_js();
}
}
/**
* This class contains all the options that controls how a question is displayed.
*
* Normally, what will happen is that the calling code will set up some display
* options to indicate what sort of question display it wants, and then before the
* question is rendered, the behaviour will be given a chance to modify the
* display options, so that, for example, A question that is finished will only
* be shown read-only, and a question that has not been submitted will not have
* any sort of feedback displayed.
*
* @copyright 2009 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_display_options {
/**#@+
* @var integer named constants for the values that most of the options take.
*/
const SHOW_ALL = -1;
const HIDDEN = 0;
const VISIBLE = 1;
const EDITABLE = 2;
/**#@-*/
/**#@+ @var integer named constants for the {@link $marks} option. */
const MAX_ONLY = 1;
const MARK_AND_MAX = 2;
/**#@-*/
/**
* @var integer maximum value for the {@link $markpd} option. This is
* effectively set by the database structure, which uses NUMBER(12,7) columns
* for question marks/fractions.
*/
const MAX_DP = 7;
/**
* @var boolean whether the question should be displayed as a read-only review,
* or in an active state where you can change the answer.
*/
public $readonly = false;
/**
* @var boolean whether the question type should output hidden form fields
* to reset any incorrect parts of the resonse to blank.
*/
public $clearwrong = false;
/**
* Should the student have what they got right and wrong clearly indicated.
* This includes the green/red hilighting of the bits of their response,
* whether the one-line summary of the current state of the question says
* correct/incorrect or just answered.
* @var integer {@link question_display_options::HIDDEN} or
* {@link question_display_options::VISIBLE}
*/
public $correctness = self::VISIBLE;
/**
* The the mark and/or the maximum available mark for this question be visible?
* @var integer {@link question_display_options::HIDDEN},
* {@link question_display_options::MAX_ONLY} or {@link question_display_options::MARK_AND_MAX}
*/
public $marks = self::MARK_AND_MAX;
/** @var number of decimal places to use when formatting marks for output. */
public $markdp = 2;
/**
* Should the flag this question UI element be visible, and if so, should the
* flag state be changable?
* @var integer {@link question_display_options::HIDDEN},
* {@link question_display_options::VISIBLE} or {@link question_display_options::EDITABLE}
*/
public $flags = self::VISIBLE;
/**
* Should the specific feedback be visible.
* @var integer {@link question_display_options::HIDDEN} or
* {@link question_display_options::VISIBLE}
*/
public $feedback = self::VISIBLE;
/**
* For questions with a number of sub-parts (like matching, or
* multiple-choice, multiple-reponse) display the number of sub-parts that
* were correct.
* @var integer {@link question_display_options::HIDDEN} or
* {@link question_display_options::VISIBLE}
*/
public $numpartscorrect = self::VISIBLE;
/**
* Should the general feedback be visible?
* @var integer {@link question_display_options::HIDDEN} or
* {@link question_display_options::VISIBLE}
*/
public $generalfeedback = self::VISIBLE;
/**
* Should the automatically generated display of what the correct answer is
* be visible?
* @var integer {@link question_display_options::HIDDEN} or
* {@link question_display_options::VISIBLE}
*/
public $rightanswer = self::VISIBLE;
/**
* Should the manually added marker's comment be visible. Should the link for
* adding/editing the comment be there.
* @var integer {@link question_display_options::HIDDEN},
* {@link question_display_options::VISIBLE}, or {@link question_display_options::EDITABLE}.
* Editable means that form fields are displayed inline.
*/
public $manualcomment = self::VISIBLE;
/**
* Should we show a 'Make comment or override grade' link?
* @var string base URL for the edit comment script, which will be shown if
* $manualcomment = self::VISIBLE.
*/
public $manualcommentlink = null;
/**
* Used in places like the question history table, to show a link to review
* this question in a certain state. If blank, a link is not shown.
* @var moodle_url base URL for a review question script.
*/
public $questionreviewlink = null;
/**
* Should the history of previous question states table be visible?
* @var integer {@link question_display_options::HIDDEN} or
* {@link question_display_options::VISIBLE}
*/
public $history = self::HIDDEN;
/**
* @since 2.9
* @var string extra HTML to include at the end of the outcome (feedback) box
* of the question display.
*
* This field is now badly named. The place it included is was changed
* (for the better) but the name was left unchanged for backwards compatibility.
*/
public $extrainfocontent = '';
/**
* @since 2.9
* @var string extra HTML to include in the history box of the question display,
* if it is shown.
*/
public $extrahistorycontent = '';
/**
* If not empty, then a link to edit the question will be included in
* the info box for the question.
*
* If used, this array must contain an element courseid or cmid.
*
* It shoudl also contain a parameter returnurl => moodle_url giving a
* sensible URL to go back to when the editing form is submitted or cancelled.
*
* @var array url parameter for the edit link. id => questiosnid will be
* added automatically.
*/
public $editquestionparams = array();
/**
* @var context the context the attempt being output belongs to.
*/
public $context;
/**
* @var int The option to show the action author in the response history.
*/
public $userinfoinhistory = self::HIDDEN;
/**
> * This identifier should be added to the labels of all input fields in the question.
* Set all the feedback-related fields {@link $feedback}, {@link generalfeedback},
> *
* {@link rightanswer} and {@link manualcomment} to
> * This is so people using assistive technology can easily tell which input belong to
* {@link question_display_options::HIDDEN}.
> * which question. The helper {@see self::add_question_identifier_to_label() makes this easier.
*/
> *
public function hide_all_feedback() {
> * If not set before the question is rendered, then it defaults to 'Question N'.
$this->feedback = self::HIDDEN;
> * (lang string)
$this->numpartscorrect = self::HIDDEN;
> *
$this->generalfeedback = self::HIDDEN;
> * @var string The identifier that the question being rendered is associated with.
$this->rightanswer = self::HIDDEN;
> * E.g. The question number when it is rendered on a quiz.
$this->manualcomment = self::HIDDEN;
> */
$this->correctness = self::HIDDEN;
> public $questionidentifier = null;
}
>
> /**
/**
* Returns the valid choices for the number of decimal places for showing
* question marks. For use in the user interface.
*
* Calling code should probably use {@link question_engine::get_dp_options()}
* rather than calling this method directly.
*
* @return array suitable for passing to {@link html_writer::select()} or similar.
*/
public static function get_dp_options() {
$options = array();
for ($i = 0; $i <= self::MAX_DP; $i += 1) {
$options[$i] = $i;
}
return $options;
}
>
}
> /**
> * Helper to add the question identify (if there is one) to the label of an input field in a question.
> *
/**
> * @param string $label The plain field label. E.g. 'Answer 1'
* Contains the logic for handling question flags.
> * @param bool $sridentifier If true, the question identifier, if added, will be wrapped in a sr-only span. Default false.
*
> * @param bool $addbefore If true, the question identifier will be added before the label.
* @copyright 2010 The Open University
> * @return string The amended label. For example 'Answer 1, Question 1'.
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
> */
*/
> public function add_question_identifier_to_label(string $label, bool $sridentifier = false, bool $addbefore = false): string {
abstract class question_flags {
> if (!$this->has_question_identifier()) {
/**
> return $label;
* Get the checksum that validates that a toggle request is valid.
> }
* @param int $qubaid the question usage id.
> $identifier = $this->questionidentifier;
* @param int $questionid the question id.
> if ($sridentifier) {
* @param int $sessionid the question_attempt id.
> $identifier = html_writer::span($identifier, 'sr-only');
* @param object $user the user. If null, defaults to $USER.
> }
* @return string that needs to be sent to question/toggleflag.php for it to work.
> $fieldlang = 'fieldinquestion';
*/
> if ($addbefore) {
protected static function get_toggle_checksum($qubaid, $questionid,
> $fieldlang = 'fieldinquestionpre';
$qaid, $slot, $user = null) {
> }
if (is_null($user)) {
> return get_string($fieldlang, 'question', (object)['fieldname' => $label, 'questionindentifier' => $identifier]);
global $USER;
> }
$user = $USER;
>
}
> /**
return md5($qubaid . "_" . $user->secret . "_" . $questionid . "_" . $qaid . "_" . $slot);
> * Whether a question number has been provided for the question that is being displayed.
}
> *
> * @return bool
/**
> */
* Get the postdata that needs to be sent to question/toggleflag.php to change the flag state.
> public function has_question_identifier(): bool {
* You need to append &newstate=0/1 to this.
> return $this->questionidentifier !== null && trim($this->questionidentifier) !== '';
* @return the post data to send.
> }
*/
public static function get_postdata(question_attempt $qa) {
$qaid = $qa->get_database_id();
$qubaid = $qa->get_usage_id();
$qid = $qa->get_question_id();
$slot = $qa->get_slot();
$checksum = self::get_toggle_checksum($qubaid, $qid, $qaid, $slot);
return "qaid={$qaid}&qubaid={$qubaid}&qid={$qid}&slot={$slot}&checksum={$checksum}&sesskey=" .
sesskey() . '&newstate=';
}
/**
* If the request seems valid, update the flag state of a question attempt.
* Throws exceptions if this is not a valid update request.
* @param int $qubaid the question usage id.
* @param int $questionid the question id.
* @param int $sessionid the question_attempt id.
* @param string $checksum checksum, as computed by {@link get_toggle_checksum()}
* corresponding to the last three arguments.
* @param bool $newstate the new state of the flag. true = flagged.
*/
public static function update_flag($qubaid, $questionid, $qaid, $slot, $checksum, $newstate) {
// Check the checksum - it is very hard to know who a question session belongs
// to, so we require that checksum parameter is matches an md5 hash of the
// three ids and the users username. Since we are only updating a flag, that
// probably makes it sufficiently difficult for malicious users to toggle
// other users flags.
if ($checksum != self::get_toggle_checksum($qubaid, $questionid, $qaid, $slot)) {
throw new moodle_exception('errorsavingflags', 'question');
}
$dm = new question_engine_data_mapper();
$dm->update_question_attempt_flag($qubaid, $questionid, $qaid, $slot, $newstate);
}
public static function initialise_js() {
global $CFG, $PAGE, $OUTPUT;
static $done = false;
if ($done) {
return;
}
$module = array(
'name' => 'core_question_flags',
'fullpath' => '/question/flags.js',
'requires' => array('base', 'dom', 'event-delegate', 'io-base'),
);
$actionurl = $CFG->wwwroot . '/question/toggleflag.php';
$flagattributes = array(
0 => array(
'src' => $OUTPUT->image_url('i/unflagged') . '',
'title' => get_string('clicktoflag', 'question'),
'alt' => get_string('flagged', 'question'), // Label on toggle should not change.
'text' => get_string('clickflag', 'question'),
),
1 => array(
'src' => $OUTPUT->image_url('i/flagged') . '',
'title' => get_string('clicktounflag', 'question'),
'alt' => get_string('flagged', 'question'),
'text' => get_string('clickunflag', 'question'),
),
);
$PAGE->requires->js_init_call('M.core_question_flags.init',
array($actionurl, $flagattributes), false, $module);
$done = true;
}
}
/**
* Exception thrown when the system detects that a student has done something
* out-of-order to a question. This can happen, for example, if they click
* the browser's back button in a quiz, then try to submit a different response.
*
* @copyright 2010 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_out_of_sequence_exception extends moodle_exception {
public function __construct($qubaid, $slot, $postdata) {
if ($postdata == null) {
$postdata = data_submitted();
}
parent::__construct('submissionoutofsequence', 'question', '', null,
"QUBAid: {$qubaid}, slot: {$slot}, post data: " . print_r($postdata, true));
}
}
/**
* Useful functions for writing question types and behaviours.
*
* @copyright 2010 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class question_utils {
/**
* @var float tolerance to use when comparing question mark/fraction values.
*
* When comparing floating point numbers in a computer, the representation is not
* necessarily exact. Therefore, we need to allow a tolerance.
* Question marks are stored in the database as decimal numbers with 7 decimal places.
* Therefore, this is the appropriate tolerance to use.
*/
const MARK_TOLERANCE = 0.00000005;
/**
* Tests to see whether two arrays have the same keys, with the same values
* (as compared by ===) for each key. However, the order of the arrays does
* not have to be the same.
* @param array $array1 the first array.
* @param array $array2 the second array.
* @return bool whether the two arrays have the same keys with the same
* corresponding values.
*/
public static function arrays_have_same_keys_and_values(array $array1, array $array2) {
if (count($array1) != count($array2)) {
return false;
}
foreach ($array1 as $key => $value1) {
if (!array_key_exists($key, $array2)) {
return false;
}
if (((string) $value1) !== ((string) $array2[$key])) {
return false;
}
}
return true;
}
/**
* Tests to see whether two arrays have the same value at a particular key.
* This method will return true if:
* 1. Neither array contains the key; or
* 2. Both arrays contain the key, and the corresponding values compare
* identical when cast to strings and compared with ===.
* @param array $array1 the first array.
* @param array $array2 the second array.
* @param string $key an array key.
* @return bool whether the two arrays have the same value (or lack of
* one) for a given key.
*/
public static function arrays_same_at_key(array $array1, array $array2, $key) {
if (array_key_exists($key, $array1) && array_key_exists($key, $array2)) {
return ((string) $array1[$key]) === ((string) $array2[$key]);
}
if (!array_key_exists($key, $array1) && !array_key_exists($key, $array2)) {
return true;
}
return false;
}
/**
* Tests to see whether two arrays have the same value at a particular key.
* Missing values are replaced by '', and then the values are cast to
* strings and compared with ===.
* @param array $array1 the first array.
* @param array $array2 the second array.
* @param string $key an array key.
* @return bool whether the two arrays have the same value (or lack of
* one) for a given key.
*/
public static function arrays_same_at_key_missing_is_blank(
array $array1, array $array2, $key) {
if (array_key_exists($key, $array1)) {
$value1 = $array1[$key];
} else {
$value1 = '';
}
if (array_key_exists($key, $array2)) {
$value2 = $array2[$key];
} else {
$value2 = '';
}
return ((string) $value1) === ((string) $value2);
}
/**
* Tests to see whether two arrays have the same value at a particular key.
* Missing values are replaced by 0, and then the values are cast to
* integers and compared with ===.
* @param array $array1 the first array.
* @param array $array2 the second array.
* @param string $key an array key.
* @return bool whether the two arrays have the same value (or lack of
* one) for a given key.
*/
public static function arrays_same_at_key_integer(
array $array1, array $array2, $key) {
if (array_key_exists($key, $array1)) {
$value1 = (int) $array1[$key];
} else {
$value1 = 0;
}
if (array_key_exists($key, $array2)) {
$value2 = (int) $array2[$key];
} else {
$value2 = 0;
}
return $value1 === $value2;
}
private static $units = array('', 'i', 'ii', 'iii', 'iv', 'v', 'vi', 'vii', 'viii', 'ix');
private static $tens = array('', 'x', 'xx', 'xxx', 'xl', 'l', 'lx', 'lxx', 'lxxx', 'xc');
private static $hundreds = array('', 'c', 'cc', 'ccc', 'cd', 'd', 'dc', 'dcc', 'dccc', 'cm');
private static $thousands = array('', 'm', 'mm', 'mmm');
/**
* Convert an integer to roman numerals.
* @param int $number an integer between 1 and 3999 inclusive. Anything else
* will throw an exception.
* @return string the number converted to lower case roman numerals.
*/
public static function int_to_roman($number) {
if (!is_integer($number) || $number < 1 || $number > 3999) {
throw new coding_exception('Only integers between 0 and 3999 can be ' .
'converted to roman numerals.', $number);
}
< return self::$thousands[$number / 1000 % 10] . self::$hundreds[$number / 100 % 10] .
< self::$tens[$number / 10 % 10] . self::$units[$number % 10];
> return self::$thousands[floor($number / 1000) % 10] . self::$hundreds[floor($number / 100) % 10] .
> self::$tens[floor($number / 10) % 10] . self::$units[$number % 10];
}
/**
* Convert an integer to a letter of alphabet.
* @param int $number an integer between 1 and 26 inclusive.
* Anything else will throw an exception.
* @return string the number converted to upper case letter of alphabet.
*/
public static function int_to_letter($number) {
$alphabet = [
'1' => 'A',
'2' => 'B',
'3' => 'C',
'4' => 'D',
'5' => 'E',
'6' => 'F',
'7' => 'G',
'8' => 'H',
'9' => 'I',
'10' => 'J',
'11' => 'K',
'12' => 'L',
'13' => 'M',
'14' => 'N',
'15' => 'O',
'16' => 'P',
'17' => 'Q',
'18' => 'R',
'19' => 'S',
'20' => 'T',
'21' => 'U',
'22' => 'V',
'23' => 'W',
'24' => 'X',
'25' => 'Y',
'26' => 'Z'
];
if (!is_integer($number) || $number < 1 || $number > count($alphabet)) {
throw new coding_exception('Only integers between 1 and 26 can be converted to letters.', $number);
}
return $alphabet[$number];
}
/**
* Typically, $mark will have come from optional_param($name, null, PARAM_RAW_TRIMMED).
* This method copes with:
* - keeping null or '' input unchanged - important to let teaches set a question back to requries grading.
* - numbers that were typed as either 1.00 or 1,00 form.
* - invalid things, which get turned into null.
*
* @param string|null $mark raw use input of a mark.
* @return float|string|null cleaned mark as a float if possible. Otherwise '' or null.
*/
public static function clean_param_mark($mark) {
if ($mark === '' || is_null($mark)) {
return $mark;
}
$mark = str_replace(',', '.', $mark);
// This regexp should match the one in validate_param.
if (!preg_match('/^[\+-]?[0-9]*\.?[0-9]*(e[-+]?[0-9]+)?$/i', $mark)) {
return null;
}
return clean_param($mark, PARAM_FLOAT);
}
/**
* Get a sumitted variable (from the GET or POST data) that is a mark.
* @param string $parname the submitted variable name.
* @return float|string|null cleaned mark as a float if possible. Otherwise '' or null.
*/
public static function optional_param_mark($parname) {
return self::clean_param_mark(
optional_param($parname, null, PARAM_RAW_TRIMMED));
}
/**
* Convert part of some question content to plain text.
* @param string $text the text.
* @param int $format the text format.
* @param array $options formatting options. Passed to {@link format_text}.
* @return float|string|null cleaned mark as a float if possible. Otherwise '' or null.
*/
public static function to_plain_text($text, $format, $options = array('noclean' => 'true')) {
// The following call to html_to_text uses the option that strips out
// all URLs, but format_text complains if it finds @@PLUGINFILE@@ tokens.
// So, we need to replace @@PLUGINFILE@@ with a real URL, but it doesn't
// matter what. We use http://example.com/.
$text = str_replace('@@PLUGINFILE@@/', 'http://example.com/', $text);
return html_to_text(format_text($text, $format, $options), 0, false);
}
/**
* Get the options required to configure the filepicker for one of the editor
* toolbar buttons.
*
* @param mixed $acceptedtypes array of types of '*'.
* @param int $draftitemid the draft area item id.
* @param context $context the context.
* @return object the required options.
*/
protected static function specific_filepicker_options($acceptedtypes, $draftitemid, $context) {
$filepickeroptions = new stdClass();
$filepickeroptions->accepted_types = $acceptedtypes;
$filepickeroptions->return_types = FILE_INTERNAL | FILE_EXTERNAL;
$filepickeroptions->context = $context;
$filepickeroptions->env = 'filepicker';
$options = initialise_filepicker($filepickeroptions);
$options->context = $context;
$options->client_id = uniqid();
$options->env = 'editor';
$options->itemid = $draftitemid;
return $options;
}
/**
* Get filepicker options for question related text areas.
*
* @param context $context the context.
* @param int $draftitemid the draft area item id.
* @return array An array of options
*/
public static function get_filepicker_options($context, $draftitemid) {
return [
'image' => self::specific_filepicker_options(['image'], $draftitemid, $context),
'media' => self::specific_filepicker_options(['video', 'audio'], $draftitemid, $context),
'link' => self::specific_filepicker_options('*', $draftitemid, $context),
];
}
/**
* Get editor options for question related text areas.
*
* @param context $context the context.
* @return array An array of options
*/
public static function get_editor_options($context) {
global $CFG;
$editoroptions = [
'subdirs' => 0,
'context' => $context,
'maxfiles' => EDITOR_UNLIMITED_FILES,
'maxbytes' => $CFG->maxbytes,
'noclean' => 0,
'trusttext' => 0,
'autosave' => false
];
return $editoroptions;
}
}
/**
* The interface for strategies for controlling which variant of each question is used.
*
* @copyright 2011 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
interface question_variant_selection_strategy {
/**
* @param int $maxvariants the num
* @param string $seed data that can be used to controls how the variant is selected
* in a semi-random way.
* @return int the variant to use, a number betweeb 1 and $maxvariants inclusive.
*/
public function choose_variant($maxvariants, $seed);
}
/**
* A {@link question_variant_selection_strategy} that is completely random.
*
* @copyright 2011 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_variant_random_strategy implements question_variant_selection_strategy {
public function choose_variant($maxvariants, $seed) {
return rand(1, $maxvariants);
}
}
/**
* A {@link question_variant_selection_strategy} that is effectively random
* for the first attempt, and then after that cycles through the available
* variants so that the students will not get a repeated variant until they have
* seen them all.
*
* @copyright 2011 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_variant_pseudorandom_no_repeats_strategy
implements question_variant_selection_strategy {
/** @var int the number of attempts this users has had, including the curent one. */
protected $attemptno;
/** @var int the user id the attempt belongs to. */
protected $userid;
/** @var string extra input fed into the pseudo-random code. */
protected $extrarandomness = '';
/**
* Constructor.
* @param int $attemptno The attempt number.
* @param int $userid the user the attempt is for (defaults to $USER->id).
*/
public function __construct($attemptno, $userid = null, $extrarandomness = '') {
$this->attemptno = $attemptno;
if (is_null($userid)) {
global $USER;
$this->userid = $USER->id;
} else {
$this->userid = $userid;
}
if ($extrarandomness) {
$this->extrarandomness = '|' . $extrarandomness;
}
}
public function choose_variant($maxvariants, $seed) {
if ($maxvariants == 1) {
return 1;
}
$hash = sha1($seed . '|user' . $this->userid . $this->extrarandomness);
$randint = hexdec(substr($hash, 17, 7));
return ($randint + $this->attemptno) % $maxvariants + 1;
}
}
/**
* A {@link question_variant_selection_strategy} designed ONLY for testing.
* For selected questions it wil return a specific variants. For the other
* slots it will use a fallback strategy.
*
* @copyright 2013 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class question_variant_forced_choices_selection_strategy
implements question_variant_selection_strategy {
/** @var array seed => variant to select. */
protected $forcedchoices;
/** @var question_variant_selection_strategy strategy used to make the non-forced choices. */
protected $basestrategy;
/**
* Constructor.
* @param array $forcedchoices array seed => variant to select.
* @param question_variant_selection_strategy $basestrategy strategy used
* to make the non-forced choices.
*/
public function __construct(array $forcedchoices, question_variant_selection_strategy $basestrategy) {
$this->forcedchoices = $forcedchoices;
$this->basestrategy = $basestrategy;
}
public function choose_variant($maxvariants, $seed) {
if (array_key_exists($seed, $this->forcedchoices)) {
if ($this->forcedchoices[$seed] > $maxvariants) {
throw new coding_exception('Forced variant out of range.');
}
return $this->forcedchoices[$seed];
} else {
return $this->basestrategy->choose_variant($maxvariants, $seed);
}
}
/**
* Helper method for preparing the $forcedchoices array.
* @param array $variantsbyslot slot number => variant to select.
* @param question_usage_by_activity $quba the question usage we need a strategy for.
* @throws coding_exception when variant cannot be forced as doesn't work.
* @return array that can be passed to the constructor as $forcedchoices.
*/
public static function prepare_forced_choices_array(array $variantsbyslot,
question_usage_by_activity $quba) {
$forcedchoices = array();
foreach ($variantsbyslot as $slot => $varianttochoose) {
$question = $quba->get_question($slot);
$seed = $question->get_variants_selection_seed();
if (array_key_exists($seed, $forcedchoices) && $forcedchoices[$seed] != $varianttochoose) {
throw new coding_exception('Inconsistent forced variant detected at slot ' . $slot);
}
if ($varianttochoose > $question->get_num_variants()) {
throw new coding_exception('Forced variant out of range at slot ' . $slot);
}
$forcedchoices[$seed] = $varianttochoose;
}
return $forcedchoices;
}
}
