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   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_ratings.
  19   *
  20   * @package    core_rating
  21   * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  namespace core_rating\privacy;
  26  
  27  use \core_privacy\local\metadata\collection;
  28  use \core_privacy\local\request\userlist;
  29  
  30  defined('MOODLE_INTERNAL') || die();
  31  
  32  require_once($CFG->dirroot . '/rating/lib.php');
  33  
  34  /**
  35   * Privacy Subsystem implementation for core_ratings.
  36   *
  37   * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
  38   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  39   */
  40  class provider implements
  41          // The ratings subsystem contains data.
  42          \core_privacy\local\metadata\provider,
  43  
  44          // The ratings subsystem is only ever used to store data for other components.
  45          // It does not store any data of its own and does not need to implement the \core_privacy\local\request\subsystem\provider
  46          // as a result.
  47  
  48          // The ratings subsystem provides a data service to other components.
  49          \core_privacy\local\request\subsystem\plugin_provider,
  50          \core_privacy\local\request\shared_userlist_provider
  51      {
  52  
  53      /**
  54       * Returns metadata about the ratings subsystem.
  55       *
  56       * @param   collection     $collection The initialised collection to add items to.
  57       * @return  collection     A listing of user data stored through the subsystem.
  58       */
  59      public static function get_metadata(collection $collection) : collection {
  60          // The table 'rating' cotains data that a user has entered.
  61          // It stores the user-entered rating alongside a mapping to describe what was mapped.
  62          $collection->add_database_table('rating', [
  63                  'rating' => 'privacy:metadata:rating:rating',
  64                  'userid' => 'privacy:metadata:rating:userid',
  65                  'timecreated' => 'privacy:metadata:rating:timecreated',
  66                  'timemodified' => 'privacy:metadata:rating:timemodified',
  67              ], 'privacy:metadata:rating');
  68  
  69          return $collection;
  70      }
  71  
  72      /**
  73       * Export all ratings which match the specified component, areaid, and itemid.
  74       *
  75       * If requesting ratings for a users own content, and you wish to include all ratings of that content, specify
  76       * $onlyuser as false.
  77       *
  78       * When requesting ratings for another users content, you should only export the ratings that the specified user
  79       * made themselves.
  80       *
  81       * @param   int         $userid The user whose information is to be exported
  82       * @param   \context    $context The context being stored.
  83       * @param   array       $subcontext The subcontext within the context to export this information
  84       * @param   string      $component The component to fetch data from
  85       * @param   string      $ratingarea The ratingarea that the data was stored in within the component
  86       * @param   int         $itemid The itemid within that ratingarea
  87       * @param   bool        $onlyuser Whether to only export ratings that the current user has made, or all ratings
  88       */
  89      public static function export_area_ratings(
  90          int $userid,
  91          \context $context,
  92          array $subcontext,
  93          string $component,
  94          string $ratingarea,
  95          int $itemid,
  96          bool $onlyuser = true
  97      ) {
  98          global $DB;
  99  
 100          $rm = new \rating_manager();
 101          $ratings = $rm->get_all_ratings_for_item((object) [
 102              'context' => $context,
 103              'component' => $component,
 104              'ratingarea' => $ratingarea,
 105              'itemid' => $itemid,
 106          ]);
 107  
 108          if ($onlyuser) {
 109              $ratings = array_filter($ratings, function($rating) use ($userid){
 110                  return ($rating->userid == $userid);
 111              });
 112          }
 113  
 114          if (empty($ratings)) {
 115              return;
 116          }
 117  
 118          $toexport = array_map(function($rating) {
 119              return (object) [
 120                  'rating' => $rating->rating,
 121                  'author' => $rating->userid,
 122              ];
 123          }, $ratings);
 124  
 125          $writer = \core_privacy\local\request\writer::with_context($context)
 126              ->export_related_data($subcontext, 'rating', $toexport);
 127      }
 128  
 129      /**
 130       * Get the SQL required to find all submission items where this user has had any involvements.
 131       *
 132       * If possible an inner join should be used.
 133       *
 134       * @param   string          $alias      The name of the table alias to use.
 135       * @param   string          $component  The na eof the component to fetch ratings for.
 136       * @param   string          $ratingarea The rating area to fetch results for.
 137       * @param   string          $itemidjoin The right-hand-side of the JOIN ON clause.
 138       * @param   int             $userid     The ID of the user being stored.
 139       * @param   bool            $innerjoin  Whether to use an inner join (preferred)
 140       * @return  \stdClass
 141       */
 142      public static function get_sql_join($alias, $component, $ratingarea, $itemidjoin, $userid, $innerjoin = false) {
 143          static $count = 0;
 144          $count++;
 145  
 146          $userwhere = '';
 147  
 148          if ($innerjoin) {
 149              // Join the rating table with the specified alias and the relevant join params.
 150              $join = "JOIN {rating} {$alias} ON ";
 151              $join .= "{$alias}.itemid = {$itemidjoin}";
 152  
 153              $userwhere .= "{$alias}.userid = :ratinguserid{$count} AND ";
 154              $userwhere .= "{$alias}.component = :ratingcomponent{$count} AND ";
 155              $userwhere .= "{$alias}.ratingarea = :ratingarea{$count}";
 156          } else {
 157              // Join the rating table with the specified alias and the relevant join params.
 158              $join = "LEFT JOIN {rating} {$alias} ON ";
 159              $join .= "{$alias}.userid = :ratinguserid{$count} AND ";
 160              $join .= "{$alias}.component = :ratingcomponent{$count} AND ";
 161              $join .= "{$alias}.ratingarea = :ratingarea{$count} AND ";
 162              $join .= "{$alias}.itemid = {$itemidjoin}";
 163  
 164              // Match against the specified user.
 165              $userwhere = "{$alias}.id IS NOT NULL";
 166          }
 167  
 168          $params = [
 169              'ratingcomponent' . $count  => $component,
 170              'ratingarea' . $count       => $ratingarea,
 171              'ratinguserid' . $count     => $userid,
 172          ];
 173  
 174          $return = (object) [
 175              'join' => $join,
 176              'params' => $params,
 177              'userwhere' => $userwhere,
 178          ];
 179          return $return;
 180      }
 181  
 182      /**
 183       * Deletes all ratings for a specified context, component, ratingarea and itemid.
 184       *
 185       * Only delete ratings when the item itself was deleted.
 186       *
 187       * We never delete ratings for one user but not others - this may affect grades, therefore ratings
 188       * made by particular user are not considered personal information.
 189       *
 190       * @param  \context $context Details about which context to delete ratings for.
 191       * @param  string $component Component to delete.
 192       * @param  string $ratingarea Rating area to delete.
 193       * @param  int $itemid The item ID for use with deletion.
 194       */
 195      public static function delete_ratings(\context $context, string $component = null,
 196              string $ratingarea = null, int $itemid = null) {
 197          global $DB;
 198  
 199          $options = ['contextid' => $context->id];
 200          if ($component) {
 201              $options['component'] = $component;
 202          }
 203          if ($ratingarea) {
 204              $options['ratingarea'] = $ratingarea;
 205          }
 206          if ($itemid) {
 207              $options['itemid'] = $itemid;
 208          }
 209  
 210          $DB->delete_records('rating', $options);
 211      }
 212  
 213      /**
 214       * Deletes all tag instances for given context, component, itemtype using subquery for itemids
 215       *
 216       * In most situations you will want to specify $userid as null. Per-user tag instances
 217       * are possible in Tags API, however there are no components or standard plugins that actually use them.
 218       *
 219       * @param  \context $context Details about which context to delete ratings for.
 220       * @param  string $component Component to delete.
 221       * @param  string $ratingarea Rating area to delete.
 222       * @param  string $itemidstest an SQL fragment that the itemid must match. Used
 223       *      in the query like WHERE itemid $itemidstest. Must use named parameters,
 224       *      and may not use named parameters called contextid, component or ratingarea.
 225       * @param array $params any query params used by $itemidstest.
 226       */
 227      public static function delete_ratings_select(\context $context, string $component,
 228               string $ratingarea, $itemidstest, $params = []) {
 229          global $DB;
 230          $params += ['contextid' => $context->id, 'component' => $component, 'ratingarea' => $ratingarea];
 231          $DB->delete_records_select('rating',
 232              'contextid = :contextid AND component = :component AND ratingarea = :ratingarea AND itemid ' . $itemidstest,
 233              $params);
 234      }
 235  
 236      /**
 237       * Add the list of users who have rated in the specified constraints.
 238       *
 239       * @param   userlist    $userlist The userlist to add the users to.
 240       * @param   string      $alias An alias prefix to use for rating selects to avoid interference with your own sql.
 241       * @param   string      $component The component to check.
 242       * @param   string      $area The rating area to check.
 243       * @param   string      $insql The SQL to use in a sub-select for the itemid query.
 244       * @param   array       $params The params required for the insql.
 245       */
 246      public static function get_users_in_context_from_sql(
 247              userlist $userlist, string $alias, string $component, string $area, string $insql, $params) {
 248          // Discussion authors.
 249          $sql = "SELECT {$alias}.userid
 250                    FROM {rating} {$alias}
 251                   WHERE {$alias}.component = :{$alias}component
 252                     AND {$alias}.ratingarea = :{$alias}ratingarea
 253                     AND {$alias}.itemid IN ({$insql})";
 254  
 255          $params["{$alias}component"] = $component;
 256          $params["{$alias}ratingarea"] = $area;
 257  
 258          $userlist->add_from_sql('userid', $sql, $params);
 259      }
 260  }