search/documents/chat_document.php

   1 <?php
   2 /**
   3 * Global Search Engine for Moodle
   4 *
   5 * @package search
   6 * @category core
   7 * @subpackage document_wrappers
   8 * @author Valery Fremaux [valery.fremaux@club-internet.fr] > 1.8
   9 * @date 2008/03/31
  10 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
  11 *
  12 * document handling for chat activity module
  13 * This file contains the mapping between a chat history and it's indexable counterpart,
  14 *
  15 * Functions for iterating and retrieving the necessary records are now also included
  16 * in this file, rather than mod/chat/lib.php
  17 *
  18 */
  19
  20 /**
  21 * includes and requires
  22 */
  23 require_once("$CFG->dirroot/search/documents/document.php");
  24 require_once("$CFG->dirroot/mod/chat/lib.php");
  25
  26 /**
  27 * a class for representing searchable information
  28 *
  29 */
  30 class ChatTrackSearchDocument extends SearchDocument {
  31
  32     /**
  33     * constructor
  34     */
  35     public function __construct(&$chatsession, $chat_module_id, $course_id, $group_id, $context_id) {
  36         // generic information; required
  37         $doc->docid         = $chat_module_id.'-'.$chatsession['sessionstart'].'-'.$chatsession['sessionend'];
  38         $doc->documenttype  = SEARCH_TYPE_CHAT;
  39         $doc->itemtype      = 'session';
  40         $doc->contextid     = $context_id;
  41
  42         $duration           = $chatsession['sessionend'] - $chatsession['sessionstart'];
  43         // we cannot call userdate with relevant locale at indexing time.
  44         $doc->title         = get_string('chatreport', 'chat').' '.get_string('openedon', 'search').' TT_'.$chatsession['sessionstart'].'_TT ('.get_string('duration', 'search').' : '.get_string('numseconds', '', $duration).')';
  45         $doc->date          = $chatsession['sessionend'];
  46
  47         //remove '(ip.ip.ip.ip)' from chat author list
  48         $doc->author        = preg_replace('/\(.*?\)/', '', $chatsession['authors']);
  49         $doc->contents      = $chatsession['content'];
  50         $doc->url           = chat_make_link($chat_module_id, $chatsession['sessionstart'], $chatsession['sessionend']);
  51
  52         // module specific information; optional
  53         $data->chat         = $chat_module_id;
  54
  55         // construct the parent class
  56         parent::__construct($doc, $data, $course_id, $group_id, 0, PATH_FOR_SEARCH_TYPE_CHAT);
  57     }
  58 }
  59
  60
  61 /**
  62 * constructs a valid link to a chat content
  63 * @param cm_id the chat course module
  64 * @param start the start time of the session
  65 * @param end th end time of the session
  66 * @uses CFG
  67 * @return a well formed link to session display
  68 */
  69 function chat_make_link($cm_id, $start, $end) {
  70     global $CFG;
  71
  72     return $CFG->wwwroot.'/mod/chat/report.php?id='.$cm_id.'&amp;start='.$start.'&amp;end='.$end;
  73 }
  74
  75 /**
  76 * fetches all the records for a given session and assemble them as a unique track
  77 * we revamped here the code of report.php for making sessions, but without any output.
  78 * note that we should collect sessions "by groups" if groupmode() is SEPARATEGROUPS.
  79 * @param int $chat_id the database
  80 * @param int $fromtime
  81 * @param int $totime
  82 * @uses CFG
  83 * @return an array of objects representing the chat sessions.
  84 */
  85 function chat_get_session_tracks($chat_id, $fromtime = 0, $totime = 0) {
  86     global $CFG;
  87
  88     $chat = get_record('chat', 'id', $chat_id);
  89     $course = get_record('course', 'id', $chat->course);
  90     $coursemodule = get_field('modules', 'id', 'name', 'data');
  91     $cm = get_record('course_modules', 'course', $course->id, 'module', $coursemodule, 'instance', $chat->id);
  92     $groupmode = groupmode($course, $cm);
  93
  94     $fromtimeclause = ($fromtime) ? "AND timestamp >= {$fromtime}" : '';
  95     $totimeclause = ($totime) ? "AND timestamp <= {$totime}" : '';
  96     $tracks = array();
  97     $messages = get_records_select('chat_messages', "chatid = '{$chat_id}' $fromtimeclause $totimeclause", "timestamp DESC");
  98     if ($messages){
  99         // splits discussions against groups
 100         $groupedMessages = array();
 101         if ($groupmode != SEPARATEGROUPS){
 102             foreach($messages as $aMessage){
 103                 $groupedMessages[$aMessage->groupid][] = $aMessage;
 104             }
 105         } else {
 106             $groupedMessages[-1] = &$messages;
 107         }
 108         $sessiongap = 5 * 60;    // 5 minutes silence means a new session
 109         $sessionend = 0;
 110         $sessionstart = 0;
 111         $sessionusers = array();
 112         $lasttime = time();
 113
 114         foreach ($groupedMessages as $groupId => $messages) {  // We are walking BACKWARDS through the messages
 115             $messagesleft = count($messages);
 116             foreach ($messages as $message) {  // We are walking BACKWARDS through the messages
 117                 $messagesleft --;              // Countdown
 118
 119                 if ($message->system) {
 120                     continue;
 121                 }
 122                 // we are within a session track
 123                 if ((($lasttime - $message->timestamp) < $sessiongap) and $messagesleft) {  // Same session
 124                     if (count($tracks) > 0){
 125                         if ($message->userid) {       // Remember user and count messages
 126                             $tracks[count($tracks) - 1]->sessionusers[$message->userid] = $message->userid;
 127                             // update last track (if exists) record appending content (remember : we go backwards)
 128                         }
 129                         $tracks[count($tracks) - 1]->content .= ' '.$message->message;
 130                         $tracks[count($tracks) - 1]->sessionstart = $message->timestamp;
 131                     }
 132                 } else {
 133                 // we initiate a new session track (backwards)
 134                     $track = new Object();
 135                     $track->sessionend = $message->timestamp;
 136                     $track->sessionstart = $message->timestamp;
 137                     $track->content = $message->message;
 138                     // reset the accumulator of users
 139                     $track->sessionusers = array();
 140                     $track->sessionusers[$message->userid] = $message->userid;
 141                     $track->groupid = $groupId;
 142                     $tracks[] = $track;
 143                 }
 144                 $lasttime = $message->timestamp;
 145             }
 146         }
 147     }
 148     return $tracks;
 149 }
 150
 151 /**
 152 * part of search engine API
 153 *
 154 */
 155 function chat_iterator() {
 156     $chatrooms = get_records('chat');
 157     return $chatrooms;
 158 }
 159
 160 /**
 161 * part of search engine API
 162 *
 163 */
 164 function chat_get_content_for_index(&$chat) {
 165     $documents = array();
 166     $course = get_record('course', 'id', $chat->course);
 167     $coursemodule = get_field('modules', 'id', 'name', 'chat');
 168     $cm = get_record('course_modules', 'course', $chat->course, 'module', $coursemodule, 'instance', $chat->id);
 169     if ($cm){
 170         $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 171
 172         // getting records for indexing
 173         $sessionTracks = chat_get_session_tracks($chat->id);
 174         if ($sessionTracks){
 175             foreach($sessionTracks as $aTrackId => $aTrack) {
 176                 foreach($aTrack->sessionusers as $aUserId){
 177                     $user = get_record('user', 'id', $aUserId);
 178                     $aTrack->authors = ($user) ? fullname($user) : '' ;
 179                     $documents[] = new ChatTrackSearchDocument(get_object_vars($aTrack), $cm->id, $chat->course, $aTrack->groupid, $context->id);
 180                 }
 181             }
 182         }
 183         return $documents;
 184     }
 185     return array();
 186 }
 187
 188 /**
 189 * returns a single data search document based on a chat_session id
 190 * chat session id is a text composite identifier made of :
 191 * - the chat id
 192 * - the timestamp when the session starts
 193 * - the timestamp when the session ends
 194 * @param id the multipart chat session id
 195 * @param itemtype the type of information (session is the only type)
 196 */
 197 function chat_single_document($id, $itemtype) {
 198     list($chat_id, $sessionstart, $sessionend) = split('-', $id);
 199     $chat = get_record('chat', 'id', $chat_id);
 200     $course = get_record('course', 'id', $chat->course);
 201     $coursemodule = get_field('modules', 'id', 'name', 'chat');
 202     $cm = get_record('course_modules', 'course', $course->id, 'module', $coursemodule, 'instance', $chat->id);
 203     if ($cm){
 204         $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 205
 206         // should be only one
 207         $tracks = chat_get_session_tracks($chat->id, $sessionstart, $sessionstart);
 208         if ($tracks){
 209             $aTrack = $tracks[0];
 210             $document = new ChatTrackSearchDocument(get_object_vars($aTrack), $cm->id, $chat->course, $aTrack->groupid, $context->id);
 211             return $document;
 212         }
 213     }
 214     return null;
 215 }
 216
 217 /**
 218 * dummy delete function that packs id with itemtype.
 219 * this was here for a reason, but I can't remember it at the moment.
 220 *
 221 */
 222 function chat_delete($info, $itemtype) {
 223     $object->id = $info;
 224     $object->itemtype = $itemtype;
 225     return $object;
 226 }
 227
 228 /**
 229 * returns the var names needed to build a sql query for addition/deletions
 230 * // TODO chat indexable records are virtual. Should proceed in a special way
 231 */
 232 function chat_db_names() {
 233     //[primary id], [table name], [time created field name], [time modified field name]
 234     return null;
 235 }
 236
 237 /**
 238 * this function handles the access policy to contents indexed as searchable documents. If this
 239 * function does not exist, the search engine assumes access is allowed.
 240 * When this point is reached, we already know that :
 241 * - user is legitimate in the surrounding context
 242 * - user may be guest and guest access is allowed to the module
 243 * - the function may perform local checks within the module information logic
 244 * @param path the access path to the module script code
 245 * @param itemtype the information subclassing (usefull for complex modules, defaults to 'standard')
 246 * @param this_id the item id within the information class denoted by entry_type. In chats, this id
 247 * points out a session history which is a close sequence of messages.
 248 * @param user the user record denoting the user who searches
 249 * @param group_id the current group used by the user when searching
 250 * @uses CFG
 251 * @return true if access is allowed, false elsewhere
 252 */
 253 function chat_check_text_access($path, $itemtype, $this_id, $user, $group_id, $context_id){
 254     global $CFG;
 255
 256     include_once("{$CFG->dirroot}/{$path}/lib.php");
 257
 258     list($chat_id, $sessionstart, $sessionend) = split('-', $id);
 259
 260     // get the chat session and all related stuff
 261     $chat = get_record('chat', 'id', $chat_id);
 262     $context = get_record('context', 'id', $context_id);
 263     $cm = get_record('course_modules', 'id', $context->instanceid);
 264     // $cm = get_coursemodule_from_instance('chat', $chat->id, $chat->course);
 265     // $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 266
 267     if (!$cm->visible and !has_capability('moodle/course:viewhiddenactivities', $context)){
 268         if (!empty($CFG->search_access_debug)) echo "search reject : hidden chat ";
 269         return false;
 270     }
 271
 272     //group consistency check : checks the following situations about groups
 273     // trap if user is not same group and groups are separated
 274     $current_group = get_current_group($course->id);
 275     $course = get_record('course', 'id', $chat->course);
 276     if ((groupmode($course, $cm) == SEPARATEGROUPS) && !ismember($group_id) && !has_capability('moodle/site:accessallgroups', $context)){
 277         if (!empty($CFG->search_access_debug)) echo "search reject : chat element is in separated group ";
 278         return false;
 279     }
 280
 281     //ownership check : checks the following situations about user
 282     // trap if user is not owner and has cannot see other's entries
 283     // TODO : typically may be stored into indexing cache
 284     if (!has_capability('mod/chat:readlog', $context)){
 285         if (!empty($CFG->search_access_debug)) echo "search reject : cannot read past sessions ";
 286         return false;
 287     }
 288
 289     return true;
 290 }
 291
 292 /**
 293 * this call back is called when displaying the link for some last post processing
 294 *
 295 */
 296 function chat_link_post_processing($title){
 297      setLocale(LC_TIME, substr(current_language(), 0, 2));
 298      $title = preg_replace('/TT_(.*)_TT/e', "userdate(\\1)", $title);
 299      return mb_convert_encoding($title, 'UTF-8', 'auto');
 300 }
 301 ?>