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Developer Documentation
See Release Notes
Long Term Support Release
- Bug fixes for general core bugs in 3.9.x will end* 10 May 2021 (12 months).
- Bug fixes for security issues in 3.9.x will end* 8 May 2023 (36 months).
- PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.
/question/engine/ -> lib.php (source)
Differences Between: [Versions 39 and 310] [Versions 39 and 311] [Versions 39 and 400] [Versions 39 and 401] [Versions 39 and 402] [Versions 39 and 403]
1 <?php 2 // This file is part of Moodle - http://moodle.org/ 3 // 4 // Moodle is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // Moodle is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU General Public License for more details. 13 // 14 // You should have received a copy of the GNU General Public License 15 // along with Moodle. If not, see <http://www.gnu.org/licenses/>. 16 17 /** 18 * This defines the core classes of the Moodle question engine. 19 * 20 * @package moodlecore 21 * @subpackage questionengine 22 * @copyright 2009 The Open University 23 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 24 */ 25 26 27 defined('MOODLE_INTERNAL') || die(); 28 29 require_once($CFG->libdir . '/filelib.php'); 30 require_once (__DIR__ . '/questionusage.php'); 31 require_once (__DIR__ . '/questionattempt.php'); 32 require_once (__DIR__ . '/questionattemptstep.php'); 33 require_once (__DIR__ . '/states.php'); 34 require_once (__DIR__ . '/datalib.php'); 35 require_once (__DIR__ . '/renderer.php'); 36 require_once (__DIR__ . '/bank.php'); 37 require_once (__DIR__ . '/../type/questiontypebase.php'); 38 require_once (__DIR__ . '/../type/questionbase.php'); 39 require_once (__DIR__ . '/../type/rendererbase.php'); 40 require_once (__DIR__ . '/../behaviour/behaviourtypebase.php'); 41 require_once (__DIR__ . '/../behaviour/behaviourbase.php'); 42 require_once (__DIR__ . '/../behaviour/rendererbase.php'); 43 require_once($CFG->libdir . '/questionlib.php'); 44 45 46 /** 47 * This static class provides access to the other question engine classes. 48 * 49 * It provides functions for managing question behaviours), and for 50 * creating, loading, saving and deleting {@link question_usage_by_activity}s, 51 * which is the main class that is used by other code that wants to use questions. 52 * 53 * @copyright 2009 The Open University 54 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 55 */ 56 abstract class question_engine { 57 /** @var array behaviour name => 1. Records which behaviours have been loaded. */ 58 private static $loadedbehaviours = array(); 59 60 /** @var array behaviour name => question_behaviour_type for this behaviour. */ 61 private static $behaviourtypes = array(); 62 63 /** 64 * Create a new {@link question_usage_by_activity}. The usage is 65 * created in memory. If you want it to persist, you will need to call 66 * {@link save_questions_usage_by_activity()}. 67 * 68 * @param string $component the plugin creating this attempt. For example mod_quiz. 69 * @param object $context the context this usage belongs to. 70 * @return question_usage_by_activity the newly created object. 71 */ 72 public static function make_questions_usage_by_activity($component, $context) { 73 return new question_usage_by_activity($component, $context); 74 } 75 76 /** 77 * Load a {@link question_usage_by_activity} from the database, based on its id. 78 * @param int $qubaid the id of the usage to load. 79 * @param moodle_database $db a database connectoin. Defaults to global $DB. 80 * @return question_usage_by_activity loaded from the database. 81 */ 82 public static function load_questions_usage_by_activity($qubaid, moodle_database $db = null) { 83 $dm = new question_engine_data_mapper($db); 84 return $dm->load_questions_usage_by_activity($qubaid); 85 } 86 87 /** 88 * Save a {@link question_usage_by_activity} to the database. This works either 89 * if the usage was newly created by {@link make_questions_usage_by_activity()} 90 * or loaded from the database using {@link load_questions_usage_by_activity()} 91 * @param question_usage_by_activity the usage to save. 92 * @param moodle_database $db a database connectoin. Defaults to global $DB. 93 */ 94 public static function save_questions_usage_by_activity(question_usage_by_activity $quba, moodle_database $db = null) { 95 $dm = new question_engine_data_mapper($db); 96 $observer = $quba->get_observer(); 97 if ($observer instanceof question_engine_unit_of_work) { 98 $observer->save($dm); 99 } else { 100 $dm->insert_questions_usage_by_activity($quba); 101 } 102 } 103 104 /** 105 * Delete a {@link question_usage_by_activity} from the database, based on its id. 106 * @param int $qubaid the id of the usage to delete. 107 */ 108 public static function delete_questions_usage_by_activity($qubaid) { 109 self::delete_questions_usage_by_activities(new qubaid_list(array($qubaid))); 110 } 111 112 /** 113 * Delete {@link question_usage_by_activity}s from the database. 114 * @param qubaid_condition $qubaids identifies which questions usages to delete. 115 */ 116 public static function delete_questions_usage_by_activities(qubaid_condition $qubaids) { 117 $dm = new question_engine_data_mapper(); 118 $dm->delete_questions_usage_by_activities($qubaids); 119 } 120 121 /** 122 * Change the maxmark for the question_attempt with number in usage $slot 123 * for all the specified question_attempts. 124 * @param qubaid_condition $qubaids Selects which usages are updated. 125 * @param int $slot the number is usage to affect. 126 * @param number $newmaxmark the new max mark to set. 127 */ 128 public static function set_max_mark_in_attempts(qubaid_condition $qubaids, 129 $slot, $newmaxmark) { 130 $dm = new question_engine_data_mapper(); 131 $dm->set_max_mark_in_attempts($qubaids, $slot, $newmaxmark); 132 } 133 134 /** 135 * Validate that the manual grade submitted for a particular question is in range. 136 * @param int $qubaid the question_usage id. 137 * @param int $slot the slot number within the usage. 138 * @return bool whether the submitted data is in range. 139 */ 140 public static function is_manual_grade_in_range($qubaid, $slot) { 141 $prefix = 'q' . $qubaid . ':' . $slot . '_'; 142 $mark = question_utils::optional_param_mark($prefix . '-mark'); 143 $maxmark = optional_param($prefix . '-maxmark', null, PARAM_FLOAT); 144 $minfraction = optional_param($prefix . ':minfraction', null, PARAM_FLOAT); 145 $maxfraction = optional_param($prefix . ':maxfraction', null, PARAM_FLOAT); 146 return $mark === '' || 147 ($mark !== null && $mark >= $minfraction * $maxmark && $mark <= $maxfraction * $maxmark) || 148 ($mark === null && $maxmark === null); 149 } 150 151 /** 152 * @param array $questionids of question ids. 153 * @param qubaid_condition $qubaids ids of the usages to consider. 154 * @return boolean whether any of these questions are being used by any of 155 * those usages. 156 */ 157 public static function questions_in_use(array $questionids, qubaid_condition $qubaids = null) { 158 if (is_null($qubaids)) { 159 return false; 160 } 161 $dm = new question_engine_data_mapper(); 162 return $dm->questions_in_use($questionids, $qubaids); 163 } 164 165 /** 166 * Get the number of times each variant has been used for each question in a list 167 * in a set of usages. 168 * @param array $questionids of question ids. 169 * @param qubaid_condition $qubaids ids of the usages to consider. 170 * @return array questionid => variant number => num uses. 171 */ 172 public static function load_used_variants(array $questionids, qubaid_condition $qubaids) { 173 $dm = new question_engine_data_mapper(); 174 return $dm->load_used_variants($questionids, $qubaids); 175 } 176 177 /** 178 * Create an archetypal behaviour for a particular question attempt. 179 * Used by {@link question_definition::make_behaviour()}. 180 * 181 * @param string $preferredbehaviour the type of model required. 182 * @param question_attempt $qa the question attempt the model will process. 183 * @return question_behaviour an instance of appropriate behaviour class. 184 */ 185 public static function make_archetypal_behaviour($preferredbehaviour, question_attempt $qa) { 186 if (!self::is_behaviour_archetypal($preferredbehaviour)) { 187 throw new coding_exception('The requested behaviour is not actually ' . 188 'an archetypal one.'); 189 } 190 191 self::load_behaviour_class($preferredbehaviour); 192 $class = 'qbehaviour_' . $preferredbehaviour; 193 return new $class($qa, $preferredbehaviour); 194 } 195 196 /** 197 * @param string $behaviour the name of a behaviour. 198 * @return array of {@link question_display_options} field names, that are 199 * not relevant to this behaviour before a 'finish' action. 200 */ 201 public static function get_behaviour_unused_display_options($behaviour) { 202 return self::get_behaviour_type($behaviour)->get_unused_display_options(); 203 } 204 205 /** 206 * With this behaviour, is it possible that a question might finish as the student 207 * interacts with it, without a call to the {@link question_attempt::finish()} method? 208 * @param string $behaviour the name of a behaviour. E.g. 'deferredfeedback'. 209 * @return bool whether with this behaviour, questions may finish naturally. 210 */ 211 public static function can_questions_finish_during_the_attempt($behaviour) { 212 return self::get_behaviour_type($behaviour)->can_questions_finish_during_the_attempt(); 213 } 214 215 /** 216 * Create a behaviour for a particular type. If that type cannot be 217 * found, return an instance of qbehaviour_missing. 218 * 219 * Normally you should use {@link make_archetypal_behaviour()}, or 220 * call the constructor of a particular model class directly. This method 221 * is only intended for use by {@link question_attempt::load_from_records()}. 222 * 223 * @param string $behaviour the type of model to create. 224 * @param question_attempt $qa the question attempt the model will process. 225 * @param string $preferredbehaviour the preferred behaviour for the containing usage. 226 * @return question_behaviour an instance of appropriate behaviour class. 227 */ 228 public static function make_behaviour($behaviour, question_attempt $qa, $preferredbehaviour) { 229 try { 230 self::load_behaviour_class($behaviour); 231 } catch (Exception $e) { 232 self::load_behaviour_class('missing'); 233 return new qbehaviour_missing($qa, $preferredbehaviour); 234 } 235 $class = 'qbehaviour_' . $behaviour; 236 return new $class($qa, $preferredbehaviour); 237 } 238 239 /** 240 * Load the behaviour class(es) belonging to a particular model. That is, 241 * include_once('/question/behaviour/' . $behaviour . '/behaviour.php'), with a bit 242 * of checking. 243 * @param string $qtypename the question type name. For example 'multichoice' or 'shortanswer'. 244 */ 245 public static function load_behaviour_class($behaviour) { 246 global $CFG; 247 if (isset(self::$loadedbehaviours[$behaviour])) { 248 return; 249 } 250 $file = $CFG->dirroot . '/question/behaviour/' . $behaviour . '/behaviour.php'; 251 if (!is_readable($file)) { 252 throw new coding_exception('Unknown question behaviour ' . $behaviour); 253 } 254 include_once($file); 255 256 $class = 'qbehaviour_' . $behaviour; 257 if (!class_exists($class)) { 258 throw new coding_exception('Question behaviour ' . $behaviour . 259 ' does not define the required class ' . $class . '.'); 260 } 261 262 self::$loadedbehaviours[$behaviour] = 1; 263 } 264 265 /** 266 * Create a behaviour for a particular type. If that type cannot be 267 * found, return an instance of qbehaviour_missing. 268 * 269 * Normally you should use {@link make_archetypal_behaviour()}, or 270 * call the constructor of a particular model class directly. This method 271 * is only intended for use by {@link question_attempt::load_from_records()}. 272 * 273 * @param string $behaviour the type of model to create. 274 * @param question_attempt $qa the question attempt the model will process. 275 * @param string $preferredbehaviour the preferred behaviour for the containing usage. 276 * @return question_behaviour_type an instance of appropriate behaviour class. 277 */ 278 public static function get_behaviour_type($behaviour) { 279 280 if (array_key_exists($behaviour, self::$behaviourtypes)) { 281 return self::$behaviourtypes[$behaviour]; 282 } 283 284 self::load_behaviour_type_class($behaviour); 285 286 $class = 'qbehaviour_' . $behaviour . '_type'; 287 if (class_exists($class)) { 288 self::$behaviourtypes[$behaviour] = new $class(); 289 } else { 290 debugging('Question behaviour ' . $behaviour . 291 ' does not define the required class ' . $class . '.', DEBUG_DEVELOPER); 292 self::$behaviourtypes[$behaviour] = new question_behaviour_type_fallback($behaviour); 293 } 294 295 return self::$behaviourtypes[$behaviour]; 296 } 297 298 /** 299 * Load the behaviour type class for a particular behaviour. That is, 300 * include_once('/question/behaviour/' . $behaviour . '/behaviourtype.php'). 301 * @param string $behaviour the behaviour name. For example 'interactive' or 'deferredfeedback'. 302 */ 303 protected static function load_behaviour_type_class($behaviour) { 304 global $CFG; 305 if (isset(self::$behaviourtypes[$behaviour])) { 306 return; 307 } 308 $file = $CFG->dirroot . '/question/behaviour/' . $behaviour . '/behaviourtype.php'; 309 if (!is_readable($file)) { 310 debugging('Question behaviour ' . $behaviour . 311 ' is missing the behaviourtype.php file.', DEBUG_DEVELOPER); 312 } 313 include_once($file); 314 } 315 316 /** 317 * Return an array where the keys are the internal names of the archetypal 318 * behaviours, and the values are a human-readable name. An 319 * archetypal behaviour is one that is suitable to pass the name of to 320 * {@link question_usage_by_activity::set_preferred_behaviour()}. 321 * 322 * @return array model name => lang string for this behaviour name. 323 */ 324 public static function get_archetypal_behaviours() { 325 $archetypes = array(); 326 $behaviours = core_component::get_plugin_list('qbehaviour'); 327 foreach ($behaviours as $behaviour => $notused) { 328 if (self::is_behaviour_archetypal($behaviour)) { 329 $archetypes[$behaviour] = self::get_behaviour_name($behaviour); 330 } 331 } 332 asort($archetypes, SORT_LOCALE_STRING); 333 return $archetypes; 334 } 335 336 /** 337 * @param string $behaviour the name of a behaviour. E.g. 'deferredfeedback'. 338 * @return bool whether this is an archetypal behaviour. 339 */ 340 public static function is_behaviour_archetypal($behaviour) { 341 return self::get_behaviour_type($behaviour)->is_archetypal(); 342 } 343 344 /** 345 * Return an array where the keys are the internal names of the behaviours 346 * in preferred order and the values are a human-readable name. 347 * 348 * @param array $archetypes, array of behaviours 349 * @param string $orderlist, a comma separated list of behaviour names 350 * @param string $disabledlist, a comma separated list of behaviour names 351 * @param string $current, current behaviour name 352 * @return array model name => lang string for this behaviour name. 353 */ 354 public static function sort_behaviours($archetypes, $orderlist, $disabledlist, $current=null) { 355 356 // Get disabled behaviours 357 if ($disabledlist) { 358 $disabled = explode(',', $disabledlist); 359 } else { 360 $disabled = array(); 361 } 362 363 if ($orderlist) { 364 $order = explode(',', $orderlist); 365 } else { 366 $order = array(); 367 } 368 369 foreach ($disabled as $behaviour) { 370 if (array_key_exists($behaviour, $archetypes) && $behaviour != $current) { 371 unset($archetypes[$behaviour]); 372 } 373 } 374 375 // Get behaviours in preferred order 376 $behaviourorder = array(); 377 foreach ($order as $behaviour) { 378 if (array_key_exists($behaviour, $archetypes)) { 379 $behaviourorder[$behaviour] = $archetypes[$behaviour]; 380 } 381 } 382 // Get the rest of behaviours and sort them alphabetically 383 $leftover = array_diff_key($archetypes, $behaviourorder); 384 asort($leftover, SORT_LOCALE_STRING); 385 386 // Set up the final order to be displayed 387 return $behaviourorder + $leftover; 388 } 389 390 /** 391 * Return an array where the keys are the internal names of the behaviours 392 * in preferred order and the values are a human-readable name. 393 * 394 * @param string $currentbehaviour 395 * @return array model name => lang string for this behaviour name. 396 */ 397 public static function get_behaviour_options($currentbehaviour) { 398 $config = question_bank::get_config(); 399 $archetypes = self::get_archetypal_behaviours(); 400 401 // If no admin setting return all behavious 402 if (empty($config->disabledbehaviours) && empty($config->behavioursortorder)) { 403 return $archetypes; 404 } 405 406 if (empty($config->behavioursortorder)) { 407 $order = ''; 408 } else { 409 $order = $config->behavioursortorder; 410 } 411 if (empty($config->disabledbehaviours)) { 412 $disabled = ''; 413 } else { 414 $disabled = $config->disabledbehaviours; 415 } 416 417 return self::sort_behaviours($archetypes, $order, $disabled, $currentbehaviour); 418 } 419 420 /** 421 * Get the translated name of a behaviour, for display in the UI. 422 * @param string $behaviour the internal name of the model. 423 * @return string name from the current language pack. 424 */ 425 public static function get_behaviour_name($behaviour) { 426 return get_string('pluginname', 'qbehaviour_' . $behaviour); 427 } 428 429 /** 430 * @return array all the file area names that may contain response files. 431 */ 432 public static function get_all_response_file_areas() { 433 $variables = array(); 434 foreach (question_bank::get_all_qtypes() as $qtype) { 435 $variables = array_merge($variables, $qtype->response_file_areas()); 436 } 437 438 $areas = array(); 439 foreach (array_unique($variables) as $variable) { 440 $areas[] = 'response_' . $variable; 441 } 442 return $areas; 443 } 444 445 /** 446 * Returns the valid choices for the number of decimal places for showing 447 * question marks. For use in the user interface. 448 * @return array suitable for passing to {@link html_writer::select()} or similar. 449 */ 450 public static function get_dp_options() { 451 return question_display_options::get_dp_options(); 452 } 453 454 /** 455 * Initialise the JavaScript required on pages where questions will be displayed. 456 * 457 * @return string 458 */ 459 public static function initialise_js() { 460 return question_flags::initialise_js(); 461 } 462 } 463 464 465 /** 466 * This class contains all the options that controls how a question is displayed. 467 * 468 * Normally, what will happen is that the calling code will set up some display 469 * options to indicate what sort of question display it wants, and then before the 470 * question is rendered, the behaviour will be given a chance to modify the 471 * display options, so that, for example, A question that is finished will only 472 * be shown read-only, and a question that has not been submitted will not have 473 * any sort of feedback displayed. 474 * 475 * @copyright 2009 The Open University 476 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 477 */ 478 class question_display_options { 479 /**#@+ @var integer named constants for the values that most of the options take. */ 480 const HIDDEN = 0; 481 const VISIBLE = 1; 482 const EDITABLE = 2; 483 /**#@-*/ 484 485 /**#@+ @var integer named constants for the {@link $marks} option. */ 486 const MAX_ONLY = 1; 487 const MARK_AND_MAX = 2; 488 /**#@-*/ 489 490 /** 491 * @var integer maximum value for the {@link $markpd} option. This is 492 * effectively set by the database structure, which uses NUMBER(12,7) columns 493 * for question marks/fractions. 494 */ 495 const MAX_DP = 7; 496 497 /** 498 * @var boolean whether the question should be displayed as a read-only review, 499 * or in an active state where you can change the answer. 500 */ 501 public $readonly = false; 502 503 /** 504 * @var boolean whether the question type should output hidden form fields 505 * to reset any incorrect parts of the resonse to blank. 506 */ 507 public $clearwrong = false; 508 509 /** 510 * Should the student have what they got right and wrong clearly indicated. 511 * This includes the green/red hilighting of the bits of their response, 512 * whether the one-line summary of the current state of the question says 513 * correct/incorrect or just answered. 514 * @var integer {@link question_display_options::HIDDEN} or 515 * {@link question_display_options::VISIBLE} 516 */ 517 public $correctness = self::VISIBLE; 518 519 /** 520 * The the mark and/or the maximum available mark for this question be visible? 521 * @var integer {@link question_display_options::HIDDEN}, 522 * {@link question_display_options::MAX_ONLY} or {@link question_display_options::MARK_AND_MAX} 523 */ 524 public $marks = self::MARK_AND_MAX; 525 526 /** @var number of decimal places to use when formatting marks for output. */ 527 public $markdp = 2; 528 529 /** 530 * Should the flag this question UI element be visible, and if so, should the 531 * flag state be changable? 532 * @var integer {@link question_display_options::HIDDEN}, 533 * {@link question_display_options::VISIBLE} or {@link question_display_options::EDITABLE} 534 */ 535 public $flags = self::VISIBLE; 536 537 /** 538 * Should the specific feedback be visible. 539 * @var integer {@link question_display_options::HIDDEN} or 540 * {@link question_display_options::VISIBLE} 541 */ 542 public $feedback = self::VISIBLE; 543 544 /** 545 * For questions with a number of sub-parts (like matching, or 546 * multiple-choice, multiple-reponse) display the number of sub-parts that 547 * were correct. 548 * @var integer {@link question_display_options::HIDDEN} or 549 * {@link question_display_options::VISIBLE} 550 */ 551 public $numpartscorrect = self::VISIBLE; 552 553 /** 554 * Should the general feedback be visible? 555 * @var integer {@link question_display_options::HIDDEN} or 556 * {@link question_display_options::VISIBLE} 557 */ 558 public $generalfeedback = self::VISIBLE; 559 560 /** 561 * Should the automatically generated display of what the correct answer is 562 * be visible? 563 * @var integer {@link question_display_options::HIDDEN} or 564 * {@link question_display_options::VISIBLE} 565 */ 566 public $rightanswer = self::VISIBLE; 567 568 /** 569 * Should the manually added marker's comment be visible. Should the link for 570 * adding/editing the comment be there. 571 * @var integer {@link question_display_options::HIDDEN}, 572 * {@link question_display_options::VISIBLE}, or {@link question_display_options::EDITABLE}. 573 * Editable means that form fields are displayed inline. 574 */ 575 public $manualcomment = self::VISIBLE; 576 577 /** 578 * Should we show a 'Make comment or override grade' link? 579 * @var string base URL for the edit comment script, which will be shown if 580 * $manualcomment = self::VISIBLE. 581 */ 582 public $manualcommentlink = null; 583 584 /** 585 * Used in places like the question history table, to show a link to review 586 * this question in a certain state. If blank, a link is not shown. 587 * @var moodle_url base URL for a review question script. 588 */ 589 public $questionreviewlink = null; 590 591 /** 592 * Should the history of previous question states table be visible? 593 * @var integer {@link question_display_options::HIDDEN} or 594 * {@link question_display_options::VISIBLE} 595 */ 596 public $history = self::HIDDEN; 597 598 /** 599 * @since 2.9 600 * @var string extra HTML to include at the end of the outcome (feedback) box 601 * of the question display. 602 * 603 * This field is now badly named. The place it included is was changed 604 * (for the better) but the name was left unchanged for backwards compatibility. 605 */ 606 public $extrainfocontent = ''; 607 608 /** 609 * @since 2.9 610 * @var string extra HTML to include in the history box of the question display, 611 * if it is shown. 612 */ 613 public $extrahistorycontent = ''; 614 615 /** 616 * If not empty, then a link to edit the question will be included in 617 * the info box for the question. 618 * 619 * If used, this array must contain an element courseid or cmid. 620 * 621 * It shoudl also contain a parameter returnurl => moodle_url giving a 622 * sensible URL to go back to when the editing form is submitted or cancelled. 623 * 624 * @var array url parameter for the edit link. id => questiosnid will be 625 * added automatically. 626 */ 627 public $editquestionparams = array(); 628 629 /** 630 * @var int the context the attempt being output belongs to. 631 */ 632 public $context; 633 634 /** 635 * Set all the feedback-related fields {@link $feedback}, {@link generalfeedback}, 636 * {@link rightanswer} and {@link manualcomment} to 637 * {@link question_display_options::HIDDEN}. 638 */ 639 public function hide_all_feedback() { 640 $this->feedback = self::HIDDEN; 641 $this->numpartscorrect = self::HIDDEN; 642 $this->generalfeedback = self::HIDDEN; 643 $this->rightanswer = self::HIDDEN; 644 $this->manualcomment = self::HIDDEN; 645 $this->correctness = self::HIDDEN; 646 } 647 648 /** 649 * Returns the valid choices for the number of decimal places for showing 650 * question marks. For use in the user interface. 651 * 652 * Calling code should probably use {@link question_engine::get_dp_options()} 653 * rather than calling this method directly. 654 * 655 * @return array suitable for passing to {@link html_writer::select()} or similar. 656 */ 657 public static function get_dp_options() { 658 $options = array(); 659 for ($i = 0; $i <= self::MAX_DP; $i += 1) { 660 $options[$i] = $i; 661 } 662 return $options; 663 } 664 } 665 666 667 /** 668 * Contains the logic for handling question flags. 669 * 670 * @copyright 2010 The Open University 671 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 672 */ 673 abstract class question_flags { 674 /** 675 * Get the checksum that validates that a toggle request is valid. 676 * @param int $qubaid the question usage id. 677 * @param int $questionid the question id. 678 * @param int $sessionid the question_attempt id. 679 * @param object $user the user. If null, defaults to $USER. 680 * @return string that needs to be sent to question/toggleflag.php for it to work. 681 */ 682 protected static function get_toggle_checksum($qubaid, $questionid, 683 $qaid, $slot, $user = null) { 684 if (is_null($user)) { 685 global $USER; 686 $user = $USER; 687 } 688 return md5($qubaid . "_" . $user->secret . "_" . $questionid . "_" . $qaid . "_" . $slot); 689 } 690 691 /** 692 * Get the postdata that needs to be sent to question/toggleflag.php to change the flag state. 693 * You need to append &newstate=0/1 to this. 694 * @return the post data to send. 695 */ 696 public static function get_postdata(question_attempt $qa) { 697 $qaid = $qa->get_database_id(); 698 $qubaid = $qa->get_usage_id(); 699 $qid = $qa->get_question_id(); 700 $slot = $qa->get_slot(); 701 $checksum = self::get_toggle_checksum($qubaid, $qid, $qaid, $slot); 702 return "qaid={$qaid}&qubaid={$qubaid}&qid={$qid}&slot={$slot}&checksum={$checksum}&sesskey=" . 703 sesskey() . '&newstate='; 704 } 705 706 /** 707 * If the request seems valid, update the flag state of a question attempt. 708 * Throws exceptions if this is not a valid update request. 709 * @param int $qubaid the question usage id. 710 * @param int $questionid the question id. 711 * @param int $sessionid the question_attempt id. 712 * @param string $checksum checksum, as computed by {@link get_toggle_checksum()} 713 * corresponding to the last three arguments. 714 * @param bool $newstate the new state of the flag. true = flagged. 715 */ 716 public static function update_flag($qubaid, $questionid, $qaid, $slot, $checksum, $newstate) { 717 // Check the checksum - it is very hard to know who a question session belongs 718 // to, so we require that checksum parameter is matches an md5 hash of the 719 // three ids and the users username. Since we are only updating a flag, that 720 // probably makes it sufficiently difficult for malicious users to toggle 721 // other users flags. 722 if ($checksum != self::get_toggle_checksum($qubaid, $questionid, $qaid, $slot)) { 723 throw new moodle_exception('errorsavingflags', 'question'); 724 } 725 726 $dm = new question_engine_data_mapper(); 727 $dm->update_question_attempt_flag($qubaid, $questionid, $qaid, $slot, $newstate); 728 } 729 730 public static function initialise_js() { 731 global $CFG, $PAGE, $OUTPUT; 732 static $done = false; 733 if ($done) { 734 return; 735 } 736 $module = array( 737 'name' => 'core_question_flags', 738 'fullpath' => '/question/flags.js', 739 'requires' => array('base', 'dom', 'event-delegate', 'io-base'), 740 ); 741 $actionurl = $CFG->wwwroot . '/question/toggleflag.php'; 742 $flagtext = array( 743 0 => get_string('clickflag', 'question'), 744 1 => get_string('clickunflag', 'question') 745 ); 746 $flagattributes = array( 747 0 => array( 748 'src' => $OUTPUT->image_url('i/unflagged') . '', 749 'title' => get_string('clicktoflag', 'question'), 750 'alt' => get_string('notflagged', 'question'), 751 // 'text' => get_string('clickflag', 'question'), 752 ), 753 1 => array( 754 'src' => $OUTPUT->image_url('i/flagged') . '', 755 'title' => get_string('clicktounflag', 'question'), 756 'alt' => get_string('flagged', 'question'), 757 // 'text' => get_string('clickunflag', 'question'), 758 ), 759 ); 760 $PAGE->requires->js_init_call('M.core_question_flags.init', 761 array($actionurl, $flagattributes, $flagtext), false, $module); 762 $done = true; 763 } 764 } 765 766 767 /** 768 * Exception thrown when the system detects that a student has done something 769 * out-of-order to a question. This can happen, for example, if they click 770 * the browser's back button in a quiz, then try to submit a different response. 771 * 772 * @copyright 2010 The Open University 773 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 774 */ 775 class question_out_of_sequence_exception extends moodle_exception { 776 public function __construct($qubaid, $slot, $postdata) { 777 if ($postdata == null) { 778 $postdata = data_submitted(); 779 } 780 parent::__construct('submissionoutofsequence', 'question', '', null, 781 "QUBAid: {$qubaid}, slot: {$slot}, post data: " . print_r($postdata, true)); 782 } 783 } 784 785 786 /** 787 * Useful functions for writing question types and behaviours. 788 * 789 * @copyright 2010 The Open University 790 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 791 */ 792 abstract class question_utils { 793 /** 794 * @var float tolerance to use when comparing question mark/fraction values. 795 * 796 * When comparing floating point numbers in a computer, the representation is not 797 * necessarily exact. Therefore, we need to allow a tolerance. 798 * Question marks are stored in the database as decimal numbers with 7 decimal places. 799 * Therefore, this is the appropriate tolerance to use. 800 */ 801 const MARK_TOLERANCE = 0.00000005; 802 803 /** 804 * Tests to see whether two arrays have the same keys, with the same values 805 * (as compared by ===) for each key. However, the order of the arrays does 806 * not have to be the same. 807 * @param array $array1 the first array. 808 * @param array $array2 the second array. 809 * @return bool whether the two arrays have the same keys with the same 810 * corresponding values. 811 */ 812 public static function arrays_have_same_keys_and_values(array $array1, array $array2) { 813 if (count($array1) != count($array2)) { 814 return false; 815 } 816 foreach ($array1 as $key => $value1) { 817 if (!array_key_exists($key, $array2)) { 818 return false; 819 } 820 if (((string) $value1) !== ((string) $array2[$key])) { 821 return false; 822 } 823 } 824 return true; 825 } 826 827 /** 828 * Tests to see whether two arrays have the same value at a particular key. 829 * This method will return true if: 830 * 1. Neither array contains the key; or 831 * 2. Both arrays contain the key, and the corresponding values compare 832 * identical when cast to strings and compared with ===. 833 * @param array $array1 the first array. 834 * @param array $array2 the second array. 835 * @param string $key an array key. 836 * @return bool whether the two arrays have the same value (or lack of 837 * one) for a given key. 838 */ 839 public static function arrays_same_at_key(array $array1, array $array2, $key) { 840 if (array_key_exists($key, $array1) && array_key_exists($key, $array2)) { 841 return ((string) $array1[$key]) === ((string) $array2[$key]); 842 } 843 if (!array_key_exists($key, $array1) && !array_key_exists($key, $array2)) { 844 return true; 845 } 846 return false; 847 } 848 849 /** 850 * Tests to see whether two arrays have the same value at a particular key. 851 * Missing values are replaced by '', and then the values are cast to 852 * strings and compared with ===. 853 * @param array $array1 the first array. 854 * @param array $array2 the second array. 855 * @param string $key an array key. 856 * @return bool whether the two arrays have the same value (or lack of 857 * one) for a given key. 858 */ 859 public static function arrays_same_at_key_missing_is_blank( 860 array $array1, array $array2, $key) { 861 if (array_key_exists($key, $array1)) { 862 $value1 = $array1[$key]; 863 } else { 864 $value1 = ''; 865 } 866 if (array_key_exists($key, $array2)) { 867 $value2 = $array2[$key]; 868 } else { 869 $value2 = ''; 870 } 871 return ((string) $value1) === ((string) $value2); 872 } 873 874 /** 875 * Tests to see whether two arrays have the same value at a particular key. 876 * Missing values are replaced by 0, and then the values are cast to 877 * integers and compared with ===. 878 * @param array $array1 the first array. 879 * @param array $array2 the second array. 880 * @param string $key an array key. 881 * @return bool whether the two arrays have the same value (or lack of 882 * one) for a given key. 883 */ 884 public static function arrays_same_at_key_integer( 885 array $array1, array $array2, $key) { 886 if (array_key_exists($key, $array1)) { 887 $value1 = (int) $array1[$key]; 888 } else { 889 $value1 = 0; 890 } 891 if (array_key_exists($key, $array2)) { 892 $value2 = (int) $array2[$key]; 893 } else { 894 $value2 = 0; 895 } 896 return $value1 === $value2; 897 } 898 899 private static $units = array('', 'i', 'ii', 'iii', 'iv', 'v', 'vi', 'vii', 'viii', 'ix'); 900 private static $tens = array('', 'x', 'xx', 'xxx', 'xl', 'l', 'lx', 'lxx', 'lxxx', 'xc'); 901 private static $hundreds = array('', 'c', 'cc', 'ccc', 'cd', 'd', 'dc', 'dcc', 'dccc', 'cm'); 902 private static $thousands = array('', 'm', 'mm', 'mmm'); 903 904 /** 905 * Convert an integer to roman numerals. 906 * @param int $number an integer between 1 and 3999 inclusive. Anything else 907 * will throw an exception. 908 * @return string the number converted to lower case roman numerals. 909 */ 910 public static function int_to_roman($number) { 911 if (!is_integer($number) || $number < 1 || $number > 3999) { 912 throw new coding_exception('Only integers between 0 and 3999 can be ' . 913 'converted to roman numerals.', $number); 914 } 915 916 return self::$thousands[$number / 1000 % 10] . self::$hundreds[$number / 100 % 10] . 917 self::$tens[$number / 10 % 10] . self::$units[$number % 10]; 918 } 919 920 /** 921 * Convert an integer to a letter of alphabet. 922 * @param int $number an integer between 1 and 26 inclusive. 923 * Anything else will throw an exception. 924 * @return string the number converted to upper case letter of alphabet. 925 */ 926 public static function int_to_letter($number) { 927 $alphabet = [ 928 '1' => 'A', 929 '2' => 'B', 930 '3' => 'C', 931 '4' => 'D', 932 '5' => 'E', 933 '6' => 'F', 934 '7' => 'G', 935 '8' => 'H', 936 '9' => 'I', 937 '10' => 'J', 938 '11' => 'K', 939 '12' => 'L', 940 '13' => 'M', 941 '14' => 'N', 942 '15' => 'O', 943 '16' => 'P', 944 '17' => 'Q', 945 '18' => 'R', 946 '19' => 'S', 947 '20' => 'T', 948 '21' => 'U', 949 '22' => 'V', 950 '23' => 'W', 951 '24' => 'X', 952 '25' => 'Y', 953 '26' => 'Z' 954 ]; 955 if (!is_integer($number) || $number < 1 || $number > count($alphabet)) { 956 throw new coding_exception('Only integers between 1 and 26 can be converted to letters.', $number); 957 } 958 return $alphabet[$number]; 959 } 960 961 /** 962 * Typically, $mark will have come from optional_param($name, null, PARAM_RAW_TRIMMED). 963 * This method copes with: 964 * - keeping null or '' input unchanged - important to let teaches set a question back to requries grading. 965 * - numbers that were typed as either 1.00 or 1,00 form. 966 * - invalid things, which get turned into null. 967 * 968 * @param string|null $mark raw use input of a mark. 969 * @return float|string|null cleaned mark as a float if possible. Otherwise '' or null. 970 */ 971 public static function clean_param_mark($mark) { 972 if ($mark === '' || is_null($mark)) { 973 return $mark; 974 } 975 976 $mark = str_replace(',', '.', $mark); 977 // This regexp should match the one in validate_param. 978 if (!preg_match('/^[\+-]?[0-9]*\.?[0-9]*(e[-+]?[0-9]+)?$/i', $mark)) { 979 return null; 980 } 981 982 return clean_param($mark, PARAM_FLOAT); 983 } 984 985 /** 986 * Get a sumitted variable (from the GET or POST data) that is a mark. 987 * @param string $parname the submitted variable name. 988 * @return float|string|null cleaned mark as a float if possible. Otherwise '' or null. 989 */ 990 public static function optional_param_mark($parname) { 991 return self::clean_param_mark( 992 optional_param($parname, null, PARAM_RAW_TRIMMED)); 993 } 994 995 /** 996 * Convert part of some question content to plain text. 997 * @param string $text the text. 998 * @param int $format the text format. 999 * @param array $options formatting options. Passed to {@link format_text}. 1000 * @return float|string|null cleaned mark as a float if possible. Otherwise '' or null. 1001 */ 1002 public static function to_plain_text($text, $format, $options = array('noclean' => 'true')) { 1003 // The following call to html_to_text uses the option that strips out 1004 // all URLs, but format_text complains if it finds @@PLUGINFILE@@ tokens. 1005 // So, we need to replace @@PLUGINFILE@@ with a real URL, but it doesn't 1006 // matter what. We use http://example.com/. 1007 $text = str_replace('@@PLUGINFILE@@/', 'http://example.com/', $text); 1008 return html_to_text(format_text($text, $format, $options), 0, false); 1009 } 1010 1011 /** 1012 * Get the options required to configure the filepicker for one of the editor 1013 * toolbar buttons. 1014 * @param mixed $acceptedtypes array of types of '*'. 1015 * @param int $draftitemid the draft area item id. 1016 * @param object $context the context. 1017 * @return object the required options. 1018 */ 1019 protected static function specific_filepicker_options($acceptedtypes, $draftitemid, $context) { 1020 $filepickeroptions = new stdClass(); 1021 $filepickeroptions->accepted_types = $acceptedtypes; 1022 $filepickeroptions->return_types = FILE_INTERNAL | FILE_EXTERNAL; 1023 $filepickeroptions->context = $context; 1024 $filepickeroptions->env = 'filepicker'; 1025 1026 $options = initialise_filepicker($filepickeroptions); 1027 $options->context = $context; 1028 $options->client_id = uniqid(); 1029 $options->env = 'editor'; 1030 $options->itemid = $draftitemid; 1031 1032 return $options; 1033 } 1034 1035 /** 1036 * Get filepicker options for question related text areas. 1037 * @param object $context the context. 1038 * @param int $draftitemid the draft area item id. 1039 * @return array An array of options 1040 */ 1041 public static function get_filepicker_options($context, $draftitemid) { 1042 return [ 1043 'image' => self::specific_filepicker_options(['image'], $draftitemid, $context), 1044 'media' => self::specific_filepicker_options(['video', 'audio'], $draftitemid, $context), 1045 'link' => self::specific_filepicker_options('*', $draftitemid, $context), 1046 ]; 1047 } 1048 1049 /** 1050 * Get editor options for question related text areas. 1051 * @param object $context the context. 1052 * @return array An array of options 1053 */ 1054 public static function get_editor_options($context) { 1055 global $CFG; 1056 1057 $editoroptions = [ 1058 'subdirs' => 0, 1059 'context' => $context, 1060 'maxfiles' => EDITOR_UNLIMITED_FILES, 1061 'maxbytes' => $CFG->maxbytes, 1062 'noclean' => 0, 1063 'trusttext' => 0, 1064 'autosave' => false 1065 ]; 1066 1067 return $editoroptions; 1068 } 1069 } 1070 1071 1072 /** 1073 * The interface for strategies for controlling which variant of each question is used. 1074 * 1075 * @copyright 2011 The Open University 1076 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 1077 */ 1078 interface question_variant_selection_strategy { 1079 /** 1080 * @param int $maxvariants the num 1081 * @param string $seed data that can be used to controls how the variant is selected 1082 * in a semi-random way. 1083 * @return int the variant to use, a number betweeb 1 and $maxvariants inclusive. 1084 */ 1085 public function choose_variant($maxvariants, $seed); 1086 } 1087 1088 1089 /** 1090 * A {@link question_variant_selection_strategy} that is completely random. 1091 * 1092 * @copyright 2011 The Open University 1093 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 1094 */ 1095 class question_variant_random_strategy implements question_variant_selection_strategy { 1096 public function choose_variant($maxvariants, $seed) { 1097 return rand(1, $maxvariants); 1098 } 1099 } 1100 1101 1102 /** 1103 * A {@link question_variant_selection_strategy} that is effectively random 1104 * for the first attempt, and then after that cycles through the available 1105 * variants so that the students will not get a repeated variant until they have 1106 * seen them all. 1107 * 1108 * @copyright 2011 The Open University 1109 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 1110 */ 1111 class question_variant_pseudorandom_no_repeats_strategy 1112 implements question_variant_selection_strategy { 1113 1114 /** @var int the number of attempts this users has had, including the curent one. */ 1115 protected $attemptno; 1116 1117 /** @var int the user id the attempt belongs to. */ 1118 protected $userid; 1119 1120 /** @var string extra input fed into the pseudo-random code. */ 1121 protected $extrarandomness = ''; 1122 1123 /** 1124 * Constructor. 1125 * @param int $attemptno The attempt number. 1126 * @param int $userid the user the attempt is for (defaults to $USER->id). 1127 */ 1128 public function __construct($attemptno, $userid = null, $extrarandomness = '') { 1129 $this->attemptno = $attemptno; 1130 if (is_null($userid)) { 1131 global $USER; 1132 $this->userid = $USER->id; 1133 } else { 1134 $this->userid = $userid; 1135 } 1136 1137 if ($extrarandomness) { 1138 $this->extrarandomness = '|' . $extrarandomness; 1139 } 1140 } 1141 1142 public function choose_variant($maxvariants, $seed) { 1143 if ($maxvariants == 1) { 1144 return 1; 1145 } 1146 1147 $hash = sha1($seed . '|user' . $this->userid . $this->extrarandomness); 1148 $randint = hexdec(substr($hash, 17, 7)); 1149 1150 return ($randint + $this->attemptno) % $maxvariants + 1; 1151 } 1152 } 1153 1154 /** 1155 * A {@link question_variant_selection_strategy} designed ONLY for testing. 1156 * For selected questions it wil return a specific variants. For the other 1157 * slots it will use a fallback strategy. 1158 * 1159 * @copyright 2013 The Open University 1160 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later 1161 */ 1162 class question_variant_forced_choices_selection_strategy 1163 implements question_variant_selection_strategy { 1164 1165 /** @var array seed => variant to select. */ 1166 protected $forcedchoices; 1167 1168 /** @var question_variant_selection_strategy strategy used to make the non-forced choices. */ 1169 protected $basestrategy; 1170 1171 /** 1172 * Constructor. 1173 * @param array $forcedchoices array seed => variant to select. 1174 * @param question_variant_selection_strategy $basestrategy strategy used 1175 * to make the non-forced choices. 1176 */ 1177 public function __construct(array $forcedchoices, question_variant_selection_strategy $basestrategy) { 1178 $this->forcedchoices = $forcedchoices; 1179 $this->basestrategy = $basestrategy; 1180 } 1181 1182 public function choose_variant($maxvariants, $seed) { 1183 if (array_key_exists($seed, $this->forcedchoices)) { 1184 if ($this->forcedchoices[$seed] > $maxvariants) { 1185 throw new coding_exception('Forced variant out of range.'); 1186 } 1187 return $this->forcedchoices[$seed]; 1188 } else { 1189 return $this->basestrategy->choose_variant($maxvariants, $seed); 1190 } 1191 } 1192 1193 /** 1194 * Helper method for preparing the $forcedchoices array. 1195 * @param array $variantsbyslot slot number => variant to select. 1196 * @param question_usage_by_activity $quba the question usage we need a strategy for. 1197 * @throws coding_exception when variant cannot be forced as doesn't work. 1198 * @return array that can be passed to the constructor as $forcedchoices. 1199 */ 1200 public static function prepare_forced_choices_array(array $variantsbyslot, 1201 question_usage_by_activity $quba) { 1202 1203 $forcedchoices = array(); 1204 1205 foreach ($variantsbyslot as $slot => $varianttochoose) { 1206 $question = $quba->get_question($slot); 1207 $seed = $question->get_variants_selection_seed(); 1208 if (array_key_exists($seed, $forcedchoices) && $forcedchoices[$seed] != $varianttochoose) { 1209 throw new coding_exception('Inconsistent forced variant detected at slot ' . $slot); 1210 } 1211 if ($varianttochoose > $question->get_num_variants()) { 1212 throw new coding_exception('Forced variant out of range at slot ' . $slot); 1213 } 1214 $forcedchoices[$seed] = $varianttochoose; 1215 } 1216 return $forcedchoices; 1217 } 1218 }
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