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Differences Between: [Versions 311 and 400] [Versions 311 and 401] [Versions 311 and 402] [Versions 311 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   * Privacy Subsystem implementation for core_question.
  19   *
  20   * @package    core_question
  21   * @category   privacy
  22   * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
  23   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24   */
  25  
  26  namespace core_question\privacy;
  27  
  28  use core_privacy\local\metadata\collection;
  29  use core_privacy\local\request\approved_contextlist;
  30  use core_privacy\local\request\approved_userlist;
  31  use core_privacy\local\request\contextlist;
  32  use core_privacy\local\request\transform;
  33  use core_privacy\local\request\userlist;
  34  use core_privacy\local\request\writer;
  35  
  36  defined('MOODLE_INTERNAL') || die();
  37  
  38  require_once($CFG->libdir . '/questionlib.php');
  39  require_once($CFG->dirroot . '/question/format.php');
  40  require_once($CFG->dirroot . '/question/editlib.php');
  41  require_once($CFG->dirroot . '/question/engine/datalib.php');
  42  
  43  /**
  44   * Privacy Subsystem implementation for core_question.
  45   *
  46   * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
  47   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  48   */
  49  class provider implements
  50      // This component has data.
  51      // We need to return all question information where the user is
  52      // listed in either the question.createdby or question.modifiedby fields.
  53      // We may also need to fetch this informtion from individual plugins in some cases.
  54      // e.g. to fetch the full and other question-specific meta-data.
  55      \core_privacy\local\metadata\provider,
  56  
  57      // This is a subsysytem which provides information to core.
  58      \core_privacy\local\request\subsystem\provider,
  59  
  60      // This is a subsysytem which provides information to plugins.
  61      \core_privacy\local\request\subsystem\plugin_provider,
  62  
  63      // This plugin is capable of determining which users have data within it.
  64      \core_privacy\local\request\core_userlist_provider,
  65  
  66      // This plugin is capable of determining which users have data within it for the plugins it provides data to.
  67      \core_privacy\local\request\shared_userlist_provider
  68  {
  69  
  70      /**
  71       * Describe the types of data stored by the question subsystem.
  72       *
  73       * @param   collection  $items  The collection to add metadata to.
  74       * @return  collection  The array of metadata
  75       */
  76      public static function get_metadata(collection $items) : collection {
  77          // Other tables link against it.
  78  
  79          // The 'question_usages' table does not contain any user data.
  80          // The table links the but doesn't store itself.
  81  
  82          // The 'question_attempts' table contains data about question attempts.
  83          // It does not contain any user ids - these are stored by the caller.
  84          $items->add_database_table('question_attempts', [
  85              'flagged'           => 'privacy:metadata:database:question_attempts:flagged',
  86              'responsesummary'   => 'privacy:metadata:database:question_attempts:responsesummary',
  87              'timemodified'      => 'privacy:metadata:database:question_attempts:timemodified',
  88          ], 'privacy:metadata:database:question_attempts');;
  89  
  90          // The 'question_attempt_steps' table contains data about changes to the state of a question attempt.
  91          $items->add_database_table('question_attempt_steps', [
  92              'state'             => 'privacy:metadata:database:question_attempt_steps:state',
  93              'timecreated'       => 'privacy:metadata:database:question_attempt_steps:timecreated',
  94              'fraction'          => 'privacy:metadata:database:question_attempt_steps:fraction',
  95              'userid'            => 'privacy:metadata:database:question_attempt_steps:userid',
  96          ], 'privacy:metadata:database:question_attempt_steps');
  97  
  98          // The 'question_attempt_step_data' table contains specific all metadata for each state.
  99          $items->add_database_table('question_attempt_step_data', [
 100              'name'              => 'privacy:metadata:database:question_attempt_step_data:name',
 101              'value'             => 'privacy:metadata:database:question_attempt_step_data:value',
 102          ], 'privacy:metadata:database:question_attempt_step_data');
 103  
 104          // These are all part of the set of the question definition
 105          // The 'question' table is used to store instances of each question.
 106          // It contains a createdby and modifiedby which related to specific users.
 107          $items->add_database_table('question', [
 108              'name'              => 'privacy:metadata:database:question:name',
 109              'questiontext'      => 'privacy:metadata:database:question:questiontext',
 110              'generalfeedback'   => 'privacy:metadata:database:question:generalfeedback',
 111              'timecreated'       => 'privacy:metadata:database:question:timecreated',
 112              'timemodified'      => 'privacy:metadata:database:question:timemodified',
 113              'createdby'         => 'privacy:metadata:database:question:createdby',
 114              'modifiedby'        => 'privacy:metadata:database:question:modifiedby',
 115          ], 'privacy:metadata:database:question');
 116  
 117          // The 'question_answers' table is used to store the set of answers, with appropriate feedback for each question.
 118          // It does not contain user data.
 119  
 120          // The 'question_hints' table is used to store hints about the correct answer for a question.
 121          // It does not contain user data.
 122  
 123          // The 'question_categories' table contains structural information about how questions are presented in the UI.
 124          // It does not contain user data.
 125  
 126          // The 'question_statistics' table contains aggregated statistics about responses.
 127          // It does not contain any identifiable user data.
 128  
 129          // The question subsystem makes use of the qtype, qformat, and qbehaviour plugin types.
 130          $items->add_plugintype_link('qtype', [], 'privacy:metadata:link:qtype');
 131          $items->add_plugintype_link('qformat', [], 'privacy:metadata:link:qformat');
 132          $items->add_plugintype_link('qbehaviour', [], 'privacy:metadata:link:qbehaviour');
 133  
 134          return $items;
 135      }
 136  
 137      /**
 138       * Export the data for all question attempts on this question usage.
 139       *
 140       * Where a user is the owner of the usage, then the full detail of that usage will be included.
 141       * Where a user has been involved in the usage, but it is not their own usage, then only their specific
 142       * involvement will be exported.
 143       *
 144       * @param   int             $userid     The userid to export.
 145       * @param   \context        $context    The context that the question was used within.
 146       * @param   array           $usagecontext  The subcontext of this usage.
 147       * @param   int             $usage      The question usage ID.
 148       * @param   \question_display_options   $options    The display options used for formatting.
 149       * @param   bool            $isowner    Whether the user being exported is the user who used the question.
 150       */
 151      public static function export_question_usage(
 152              int $userid,
 153              \context $context,
 154              array $usagecontext,
 155              int $usage,
 156              \question_display_options $options,
 157              bool $isowner
 158          ) {
 159          // Determine the questions in this usage.
 160          $quba = \question_engine::load_questions_usage_by_activity($usage);
 161  
 162          $basepath = $usagecontext;
 163          $questionscontext = array_merge($usagecontext, [
 164              get_string('questions', 'core_question'),
 165          ]);
 166  
 167          foreach ($quba->get_attempt_iterator() as $qa) {
 168              $question = $qa->get_question(false);
 169              $slotno = $qa->get_slot();
 170              $questionnocontext = array_merge($questionscontext, [$slotno]);
 171  
 172              if ($isowner) {
 173                  // This user is the overal owner of the question attempt and all data wil therefore be exported.
 174                  //
 175                  // Respect _some_ of the question_display_options to ensure that they don't have access to
 176                  // generalfeedback and mark if the display options prevent this.
 177                  // This is defensible because they can submit questions without completing a quiz and perform an SAR to
 178                  // get prior access to the feedback and mark to improve upon it.
 179                  // Export the response.
 180                  $data = (object) [
 181                      'name' => $question->name,
 182                      'question' => $qa->get_question_summary(),
 183                      'answer' => $qa->get_response_summary(),
 184                      'timemodified' => transform::datetime($qa->timemodified),
 185                  ];
 186  
 187                  if ($options->marks >= \question_display_options::MARK_AND_MAX) {
 188                      $data->mark = $qa->format_mark($options->markdp);
 189                  }
 190  
 191                  if ($options->flags != \question_display_options::HIDDEN) {
 192                      $data->flagged = transform::yesno($qa->is_flagged());
 193                  }
 194  
 195                  if ($options->generalfeedback != \question_display_options::HIDDEN) {
 196                      $data->generalfeedback = $question->format_generalfeedback($qa);
 197                  }
 198  
 199                  if ($options->manualcomment != \question_display_options::HIDDEN) {
 200                      if ($qa->has_manual_comment()) {
 201                          // Note - the export of the step data will ensure that the files are exported.
 202                          // No need to do it again here.
 203                          list($comment, $commentformat, $step) = $qa->get_manual_comment();
 204  
 205                          $comment = writer::with_context($context)
 206                              ->rewrite_pluginfile_urls(
 207                                  $questionnocontext,
 208                                  'question',
 209                                  'response_bf_comment',
 210                                  $step->get_id(),
 211                                  $comment
 212                              );
 213                          $data->comment = $qa->get_behaviour(false)->format_comment($comment, $commentformat);
 214                      }
 215                  }
 216  
 217                  writer::with_context($context)
 218                      ->export_data($questionnocontext, $data);
 219  
 220                  // Export the step data.
 221                  static::export_question_attempt_steps($userid, $context, $questionnocontext, $qa, $options, $isowner);
 222              }
 223          }
 224      }
 225  
 226      /**
 227       * Export the data for each step transition for each question in each question attempt.
 228       *
 229       * Where a user is the owner of the usage, then all steps in the question usage will be exported.
 230       * Where a user is not the owner, but has been involved in the usage, then only their specific
 231       * involvement will be exported.
 232       *
 233       * @param   int                 $userid     The user to export for
 234       * @param   \context            $context    The context that the question was used within.
 235       * @param   array               $questionnocontext  The subcontext of this question number.
 236       * @param   \question_attempt   $qa         The attempt being checked
 237       * @param   \question_display_options   $options    The display options used for formatting.
 238       * @param   bool                $isowner    Whether the user being exported is the user who used the question.
 239       */
 240      public static function export_question_attempt_steps(
 241              int $userid,
 242              \context $context,
 243              array $questionnocontext,
 244              \question_attempt $qa,
 245              \question_display_options $options,
 246              $isowner
 247          ) {
 248          $attemptdata = (object) [
 249                  'steps' => [],
 250              ];
 251          $stepno = 0;
 252          foreach ($qa->get_step_iterator() as $i => $step) {
 253              $stepno++;
 254  
 255              if ($isowner || ($step->get_user_id() != $userid)) {
 256                  // The user is the owner, or the author of the step.
 257  
 258                  $restrictedqa = new \question_attempt_with_restricted_history($qa, $i, null);
 259                  $stepdata = (object) [
 260                      // Note: Do not include the user here.
 261                      'time' => transform::datetime($step->get_timecreated()),
 262                      'action' => $qa->summarise_action($step),
 263                  ];
 264  
 265                  if ($options->marks >= \question_display_options::MARK_AND_MAX) {
 266                      $stepdata->mark = $qa->format_fraction_as_mark($step->get_fraction(), $options->markdp);
 267                  }
 268  
 269                  if ($options->correctness != \question_display_options::HIDDEN) {
 270                      $stepdata->state = $restrictedqa->get_state_string($options->correctness);
 271                  }
 272  
 273                  if ($step->has_behaviour_var('comment')) {
 274                      $comment = $step->get_behaviour_var('comment');
 275                      $commentformat = $step->get_behaviour_var('commentformat');
 276  
 277                      if (empty(trim($comment))) {
 278                          // Skip empty comments.
 279                          continue;
 280                      }
 281  
 282                      // Format the comment.
 283                      $comment = writer::with_context($context)
 284                          ->rewrite_pluginfile_urls(
 285                              $questionnocontext,
 286                              'question',
 287                              'response_bf_comment',
 288                              $step->get_id(),
 289                              $comment
 290                          );
 291  
 292                      // Export any files associated with the comment files area.
 293                      writer::with_context($context)
 294                          ->export_area_files(
 295                              $questionnocontext,
 296                              'question',
 297                              "response_bf_comment",
 298                              $step->get_id()
 299                          );
 300  
 301                      $stepdata->comment = $qa->get_behaviour(false)->format_comment($comment, $commentformat);
 302                  }
 303  
 304                  // Export any response files associated with this step.
 305                  foreach (\question_engine::get_all_response_file_areas() as $filearea) {
 306                      writer::with_context($context)
 307                          ->export_area_files(
 308                                  $questionnocontext,
 309                                  'question',
 310                                  $filearea,
 311                                  $step->get_id()
 312                              );
 313                  }
 314  
 315                  $attemptdata->steps[$stepno] = $stepdata;
 316              }
 317          }
 318  
 319          if (!empty($attemptdata->steps)) {
 320              writer::with_context($context)
 321                  ->export_related_data($questionnocontext, 'steps', $attemptdata);
 322          }
 323      }
 324  
 325      /**
 326       * Get the list of contexts where the specified user has either created, or edited a question.
 327       *
 328       * To export usage of a question, please call {@link provider::export_question_usage()} from the module which
 329       * instantiated the usage of the question.
 330       *
 331       * @param   int             $userid The user to search.
 332       * @return  contextlist     $contextlist The contextlist containing the list of contexts used in this plugin.
 333       */
 334      public static function get_contexts_for_userid(int $userid) : contextlist {
 335          $contextlist = new contextlist();
 336  
 337          // A user may have created or updated a question.
 338          // Questions are linked against a question category, which has a contextid field.
 339          $sql = "SELECT cat.contextid
 340                    FROM {question} q
 341              INNER JOIN {question_categories} cat ON cat.id = q.category
 342                   WHERE
 343                      q.createdby = :useridcreated OR
 344                     q.modifiedby = :useridmodified";
 345          $params = [
 346              'useridcreated' => $userid,
 347              'useridmodified' => $userid,
 348          ];
 349          $contextlist->add_from_sql($sql, $params);
 350  
 351          return $contextlist;
 352      }
 353  
 354      /**
 355       * Get the list of users who have data within a context.
 356       *
 357       * @param   userlist    $userlist   The userlist containing the list of users who have data in this context/plugin combination.
 358       */
 359      public static function get_users_in_context(userlist $userlist) {
 360          $context = $userlist->get_context();
 361  
 362          // A user may have created or updated a question.
 363          // Questions are linked against a question category, which has a contextid field.
 364          $sql = "SELECT q.createdby, q.modifiedby
 365                    FROM {question} q
 366                    JOIN {question_categories} cat
 367                         ON cat.id = q.category
 368                   WHERE cat.contextid = :contextid";
 369  
 370          $params = [
 371              'contextid' => $context->id
 372          ];
 373  
 374          $userlist->add_from_sql('createdby', $sql, $params);
 375          $userlist->add_from_sql('modifiedby', $sql, $params);
 376      }
 377  
 378      /**
 379       * Determine related question usages for a user.
 380       *
 381       * @param   string          $prefix     A unique prefix to add to the table alias
 382       * @param   string          $component  The name of the component to fetch usages for.
 383       * @param   string          $joinfield  The SQL field name to use in the JOIN ON - e.g. q.usageid
 384       * @param   int             $userid     The user to search.
 385       * @return  \qubaid_join
 386       */
 387      public static function get_related_question_usages_for_user(string $prefix, string $component, string $joinfield, int $userid) : \qubaid_join {
 388          return new \qubaid_join("
 389                  JOIN {question_usages} {$prefix}_qu ON {$prefix}_qu.id = {$joinfield}
 390                   AND {$prefix}_qu.component = :{$prefix}_usagecomponent
 391                  JOIN {question_attempts} {$prefix}_qa ON {$prefix}_qa.questionusageid = {$prefix}_qu.id
 392                  JOIN {question_attempt_steps} {$prefix}_qas ON {$prefix}_qas.questionattemptid = {$prefix}_qa.id",
 393              "{$prefix}_qu.id",
 394              "{$prefix}_qas.userid = :{$prefix}_stepuserid",
 395              [
 396                  "{$prefix}_stepuserid" => $userid,
 397                  "{$prefix}_usagecomponent" => $component,
 398              ]);
 399      }
 400  
 401      /**
 402       * Add the list of users who have rated in the specified constraints.
 403       *
 404       * @param   userlist    $userlist   The userlist to add the users to.
 405       * @param   string      $prefix     A unique prefix to add to the table alias to avoid interference with your own sql.
 406       * @param   string      $insql      The SQL to use in a sub-select for the question_usages.id query.
 407       * @param   array       $params     The params required for the insql.
 408       * @param   int|null    $contextid  An optional context id, in case the $sql query is not already filtered by that.
 409       */
 410      public static function get_users_in_context_from_sql(userlist $userlist, string $prefix, string $insql, $params,
 411              int $contextid = null) {
 412  
 413          $sql = "SELECT {$prefix}_qas.userid
 414                    FROM {question_attempt_steps} {$prefix}_qas
 415                    JOIN {question_attempts} {$prefix}_qa ON {$prefix}_qas.questionattemptid = {$prefix}_qa.id
 416                    JOIN {question_usages} {$prefix}_qu ON {$prefix}_qa.questionusageid = {$prefix}_qu.id
 417                   WHERE {$prefix}_qu.id IN ({$insql})";
 418  
 419          if ($contextid) {
 420              $sql .= " AND {$prefix}_qu.contextid = :{$prefix}_contextid";
 421              $params["{$prefix}_contextid"] = $contextid;
 422          }
 423  
 424          $userlist->add_from_sql('userid', $sql, $params);
 425      }
 426  
 427      /**
 428       * Export all user data for the specified user, in the specified contexts.
 429       *
 430       * @param   approved_contextlist    $contextlist    The approved contexts to export information for.
 431       */
 432      public static function export_user_data(approved_contextlist $contextlist) {
 433          global $CFG, $DB, $SITE;
 434          if (empty($contextlist)) {
 435              return;
 436          }
 437  
 438          // Use the Moodle XML Data format.
 439          // It is the only lossless format that we support.
 440          $format = "xml";
 441          require_once($CFG->dirroot . "/question/format/{$format}/format.php");
 442  
 443          // THe export system needs questions in a particular format.
 444          // The easiest way to fetch these is with get_questions_category() which takes the details of a question
 445          // category.
 446          // We fetch the root question category for each context and the get_questions_category function recurses to
 447          // After fetching them, we filter out any not created or modified by the requestor.
 448          $user = $contextlist->get_user();
 449          $userid = $user->id;
 450  
 451          list($contextsql, $contextparams) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);
 452          $categories = $DB->get_records_select('question_categories', "contextid {$contextsql} AND parent = 0", $contextparams);
 453  
 454          $classname = "qformat_{$format}";
 455          foreach ($categories as $category) {
 456              $context = \context::instance_by_id($category->contextid);
 457  
 458              $questions = get_questions_category($category, true);
 459              $questions = array_filter($questions, function($question) use ($userid) {
 460                  return ($question->createdby == $userid) || ($question->modifiedby == $userid);
 461              }, ARRAY_FILTER_USE_BOTH);
 462  
 463              if (empty($questions)) {
 464                  continue;
 465              }
 466  
 467              $qformat = new $classname();
 468              $qformat->setQuestions($questions);
 469  
 470              $qformat->setContexts([$context]);
 471              $qformat->setContexttofile(true);
 472  
 473              // We do not know which course this belongs to, and it's not actually used except in error, so use Site.
 474              $qformat->setCourse($SITE);
 475              $content = '';
 476              if ($qformat->exportpreprocess()) {
 477                  $content = $qformat->exportprocess(false);
 478              }
 479  
 480              $subcontext = [
 481                  get_string('questionbank', 'core_question'),
 482              ];
 483              writer::with_context($context)->export_custom_file($subcontext, 'questions.xml', $content);
 484          }
 485      }
 486  
 487      /**
 488       * Delete all data for all users in the specified context.
 489       *
 490       * @param   context                 $context   The specific context to delete data for.
 491       */
 492      public static function delete_data_for_all_users_in_context(\context $context) {
 493          global $DB;
 494  
 495          // Questions are considered to be 'owned' by the institution, even if they were originally written by a specific
 496          // user. They are still exported in the list of a users data, but they are not removed.
 497          // The userid is instead anonymised.
 498  
 499          $DB->set_field_select('question', 'createdby', 0,
 500              'category IN (SELECT id FROM {question_categories} WHERE contextid = :contextid)',
 501              [
 502                  'contextid' => $context->id,
 503              ]);
 504  
 505          $DB->set_field_select('question', 'modifiedby', 0,
 506              'category IN (SELECT id FROM {question_categories} WHERE contextid = :contextid)',
 507              [
 508                  'contextid' => $context->id,
 509              ]);
 510      }
 511  
 512      /**
 513       * Delete all user data for the specified user, in the specified contexts.
 514       *
 515       * @param   approved_contextlist    $contextlist    The approved contexts and user information to delete information for.
 516       */
 517      public static function delete_data_for_user(approved_contextlist $contextlist) {
 518          global $DB;
 519  
 520          // Questions are considered to be 'owned' by the institution, even if they were originally written by a specific
 521          // user. They are still exported in the list of a users data, but they are not removed.
 522          // The userid is instead anonymised.
 523  
 524          list($contextsql, $contextparams) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);
 525          $contextparams['createdby'] = $contextlist->get_user()->id;
 526          $DB->set_field_select('question', 'createdby', 0, "
 527                  category IN (SELECT id FROM {question_categories} WHERE contextid {$contextsql})
 528              AND createdby = :createdby", $contextparams);
 529  
 530          list($contextsql, $contextparams) = $DB->get_in_or_equal($contextlist->get_contextids(), SQL_PARAMS_NAMED);
 531          $contextparams['modifiedby'] = $contextlist->get_user()->id;
 532          $DB->set_field_select('question', 'modifiedby', 0, "
 533                  category IN (SELECT id FROM {question_categories} WHERE contextid {$contextsql})
 534              AND modifiedby = :modifiedby", $contextparams);
 535      }
 536  
 537      /**
 538       * Delete multiple users within a single context.
 539       *
 540       * @param   approved_userlist   $userlist   The approved context and user information to delete information for.
 541       */
 542      public static function delete_data_for_users(approved_userlist $userlist) {
 543          global $DB;
 544  
 545          // Questions are considered to be 'owned' by the institution, even if they were originally written by a specific
 546          // user. They are still exported in the list of a users data, but they are not removed.
 547          // The userid is instead anonymised.
 548  
 549          $context = $userlist->get_context();
 550          $userids = $userlist->get_userids();
 551  
 552          list($createdbysql, $createdbyparams) = $DB->get_in_or_equal($userids, SQL_PARAMS_NAMED);
 553          list($modifiedbysql, $modifiedbyparams) = $DB->get_in_or_equal($userids, SQL_PARAMS_NAMED);
 554  
 555          $params = ['contextid' => $context->id];
 556  
 557          $DB->set_field_select('question', 'createdby', 0, "
 558                  category IN (SELECT id FROM {question_categories} WHERE contextid = :contextid)
 559              AND createdby {$createdbysql}", $params + $createdbyparams);
 560  
 561          $DB->set_field_select('question', 'modifiedby', 0, "
 562                  category IN (SELECT id FROM {question_categories} WHERE contextid = :contextid)
 563              AND modifiedby {$modifiedbysql}", $params + $modifiedbyparams);
 564      }
 565  }