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 * @contributor Tatsuva Shirai 20090530
  10 * @date 2008/03/31
  11 * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
  12 *
  13 * document handling for chat activity module
  14 * This file contains the mapping between a chat history and it's indexable counterpart,
  15 *
  16 * Functions for iterating and retrieving the necessary records are now also included
  17 * in this file, rather than mod/chat/lib.php
  18 *
  19 */
  20
  21 /**
  22 * includes and requires
  23 */
  24 require_once("$CFG->dirroot/search/documents/document.php");
  25 require_once("$CFG->dirroot/mod/chat/lib.php");
  26
  27 /**
  28 * a class for representing searchable information
  29 *
  30 */
  31 class ChatTrackSearchDocument extends SearchDocument {
  32
  33     /**
  34     * constructor
  35     */
  36     public function __construct(&$chatsession, $chat_id, $chat_module_id, $course_id, $group_id, $context_id) {
  37         // generic information; required
  38         $doc->docid         = $chat_id.'-'.$chatsession['sessionstart'].'-'.$chatsession['sessionend'];
  39         $doc->documenttype  = SEARCH_TYPE_CHAT;
  40         $doc->itemtype      = 'session';
  41         $doc->contextid     = $context_id;
  42
  43         $duration           = $chatsession['sessionend'] - $chatsession['sessionstart'];
  44         // we cannot call userdate with relevant locale at indexing time.
  45         $doc->title         = get_string('chatreport', 'chat').' '.get_string('openedon', 'search').' TT_'.$chatsession['sessionstart'].'_TT ('.get_string('duration', 'search').' : '.get_string('numseconds', '', $duration).')';
  46         $doc->date          = $chatsession['sessionend'];
  47
  48         //remove '(ip.ip.ip.ip)' from chat author list
  49         $doc->author        = preg_replace('/\(.*?\)/', '', $chatsession['authors']);
  50         $doc->contents      = $chatsession['content'];
  51         $doc->url           = chat_make_link($chat_module_id, $chatsession['sessionstart'], $chatsession['sessionend']);
  52
  53         // module specific information; optional
  54         $data->chat         = $chat_id;
  55
  56         // construct the parent class
  57         parent::__construct($doc, $data, $course_id, $group_id, 0, 'mod/'.SEARCH_TYPE_CHAT);
  58     }
  59 }
  60
  61
  62 /**
  63 * constructs a valid link to a chat content
  64 * @param cm_id the chat course module
  65 * @param start the start time of the session
  66 * @param end th end time of the session
  67 * @uses CFG
  68 * @return a well formed link to session display
  69 */
  70 function chat_make_link($cm_id, $start, $end) {
  71     global $CFG;
  72
  73     return $CFG->wwwroot.'/mod/chat/report.php?id='.$cm_id.'&amp;start='.$start.'&amp;end='.$end;
  74 }
  75
  76 /**
  77 * fetches all the records for a given session and assemble them as a unique track
  78 * we revamped here the code of report.php for making sessions, but without any output.
  79 * note that we should collect sessions "by groups" if groupmode() is SEPARATEGROUPS.
  80 * @param int $chat_id the database
  81 * @param int $fromtime
  82 * @param int $totime
  83 * @uses CFG
  84 * @return an array of objects representing the chat sessions.
  85 */
  86 function chat_get_session_tracks($chat_id, $fromtime = 0, $totime = 0) {
  87     global $CFG;
  88
  89     $chat = get_record('chat', 'id', $chat_id);
  90     $course = get_record('course', 'id', $chat->course);
  91     $coursemodule = get_field('modules', 'id', 'name', 'data');
  92     $cm = get_record('course_modules', 'course', $course->id, 'module', $coursemodule, 'instance', $chat->id);
  93     if (empty($cm)) { // Shirai 20090530
  94         mtrace("Missing this chat: Course=".$chat->course."/ ChatID=".$chat_id);
  95         return array();
  96     }
  97     $groupmode = groupmode($course, $cm);
  98
  99     $fromtimeclause = ($fromtime) ? "AND timestamp >= {$fromtime}" : '';
 100     $totimeclause = ($totime) ? "AND timestamp <= {$totime}" : '';
 101     $tracks = array();
 102     $messages = get_records_select('chat_messages', "chatid = '{$chat_id}' $fromtimeclause $totimeclause", "timestamp DESC");
 103     if ($messages){
 104         // splits discussions against groups
 105         $groupedMessages = array();
 106         if ($groupmode != SEPARATEGROUPS){
 107             foreach($messages as $aMessage){
 108                 $groupedMessages[$aMessage->groupid][] = $aMessage;
 109             }
 110         } else {
 111             $groupedMessages[-1] = &$messages;
 112         }
 113         $sessiongap = 5 * 60;    // 5 minutes silence means a new session
 114         $sessionend = 0;
 115         $sessionstart = 0;
 116         $sessionusers = array();
 117         $lasttime = time();
 118
 119         foreach ($groupedMessages as $groupId => $messages) {  // We are walking BACKWARDS through the messages
 120             $messagesleft = count($messages);
 121             foreach ($messages as $message) {  // We are walking BACKWARDS through the messages
 122                 $messagesleft --;              // Countdown
 123
 124                 if ($message->system) {
 125                     continue;
 126                 }
 127                 // we are within a session track
 128                 if ((($lasttime - $message->timestamp) < $sessiongap) and $messagesleft) {  // Same session
 129                     if (count($tracks) > 0){
 130                         if ($message->userid) {       // Remember user and count messages
 131                             $tracks[count($tracks) - 1]->sessionusers[$message->userid] = $message->userid;
 132                             // update last track (if exists) record appending content (remember : we go backwards)
 133                         }
 134                         $tracks[count($tracks) - 1]->content .= ' '.$message->message;
 135                         $tracks[count($tracks) - 1]->sessionstart = $message->timestamp;
 136                     }
 137                 } else {
 138                 // we initiate a new session track (backwards)
 139                     $track = new Object();
 140                     $track->sessionend = $message->timestamp;
 141                     $track->sessionstart = $message->timestamp;
 142                     $track->content = $message->message;
 143                     // reset the accumulator of users
 144                     $track->sessionusers = array();
 145                     $track->sessionusers[$message->userid] = $message->userid;
 146                     $track->groupid = $groupId;
 147                     $tracks[] = $track;
 148                 }
 149                 $lasttime = $message->timestamp;
 150             }
 151         }
 152     }
 153     return $tracks;
 154 }
 155
 156 /**
 157 * part of search engine API
 158 *
 159 */
 160 function chat_iterator() {
 161     $chatrooms = get_records('chat');
 162     return $chatrooms;
 163 }
 164
 165 /**
 166 * part of search engine API
 167 *
 168 */
 169 function chat_get_content_for_index(&$chat) {
 170     $documents = array();
 171     $course = get_record('course', 'id', $chat->course);
 172     $coursemodule = get_field('modules', 'id', 'name', 'chat');
 173     $cm = get_record('course_modules', 'course', $chat->course, 'module', $coursemodule, 'instance', $chat->id);
 174     if ($cm){
 175         $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 176
 177         // getting records for indexing
 178         $sessionTracks = chat_get_session_tracks($chat->id);
 179         if ($sessionTracks){
 180             foreach($sessionTracks as $aTrackId => $aTrack) {
 181                 foreach($aTrack->sessionusers as $aUserId){
 182                     $user = get_record('user', 'id', $aUserId);
 183                     $aTrack->authors = ($user) ? fullname($user) : '' ;
 184                     $documents[] = new ChatTrackSearchDocument(get_object_vars($aTrack), $chat->id, $cm->id, $chat->course, $aTrack->groupid, $context->id);
 185                 }
 186             }
 187         }
 188         return $documents;
 189     }
 190     return array();
 191 }
 192
 193 /**
 194 * returns a single data search document based on a chat_session id
 195 * chat session id is a text composite identifier made of :
 196 * - the chat id
 197 * - the timestamp when the session starts
 198 * - the timestamp when the session ends
 199 * @param id the multipart chat session id
 200 * @param itemtype the type of information (session is the only type)
 201 */
 202 function chat_single_document($id, $itemtype) {
 203     list($chat_id, $sessionstart, $sessionend) = split('-', $id);
 204     $chat = get_record('chat', 'id', $chat_id);
 205     $course = get_record('course', 'id', $chat->course);
 206     $coursemodule = get_field('modules', 'id', 'name', 'chat');
 207     $cm = get_record('course_modules', 'course', $course->id, 'module', $coursemodule, 'instance', $chat->id);
 208     if ($cm){
 209         $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 210
 211         // should be only one
 212         $tracks = chat_get_session_tracks($chat->id, $sessionstart, $sessionstart);
 213         if ($tracks){
 214             $aTrack = $tracks[0];
 215             $document = new ChatTrackSearchDocument(get_object_vars($aTrack), $chat_id, $cm->id, $chat->course, $aTrack->groupid, $context->id);
 216             return $document;
 217         }
 218     }
 219     return null;
 220 }
 221
 222 /**
 223 * dummy delete function that packs id with itemtype.
 224 * this was here for a reason, but I can't remember it at the moment.
 225 *
 226 */
 227 function chat_delete($info, $itemtype) {
 228     $object->id = $info;
 229     $object->itemtype = $itemtype;
 230     return $object;
 231 }
 232
 233 /**
 234 * returns the var names needed to build a sql query for addition/deletions
 235 * // TODO chat indexable records are virtual. Should proceed in a special way
 236 */
 237 function chat_db_names() {
 238     //[primary id], [table name], [time created field name], [time modified field name]
 239     return null;
 240 }
 241
 242 /**
 243 * this function handles the access policy to contents indexed as searchable documents. If this
 244 * function does not exist, the search engine assumes access is allowed.
 245 * When this point is reached, we already know that :
 246 * - user is legitimate in the surrounding context
 247 * - user may be guest and guest access is allowed to the module
 248 * - the function may perform local checks within the module information logic
 249 * @param path the access path to the module script code
 250 * @param itemtype the information subclassing (usefull for complex modules, defaults to 'standard')
 251 * @param this_id the item id within the information class denoted by entry_type. In chats, this id
 252 * points out a session history which is a close sequence of messages.
 253 * @param user the user record denoting the user who searches
 254 * @param group_id the current group used by the user when searching
 255 * @uses CFG
 256 * @return true if access is allowed, false elsewhere
 257 */
 258 function chat_check_text_access($path, $itemtype, $this_id, $user, $group_id, $context_id){
 259     global $CFG;
 260
 261     include_once("{$CFG->dirroot}/{$path}/lib.php");
 262
 263     list($chat_id, $sessionstart, $sessionend) = split('-', $this_id);
 264     // get the chat session and all related stuff
 265     $chat = get_record('chat', 'id', $chat_id);
 266     $context = get_record('context', 'id', $context_id);
 267     $cm = get_record('course_modules', 'id', $context->instanceid);
 268     if (empty($cm)) return false; // Shirai 20090530 - MDL19342 - course module might have been delete
 269
 270     if (!$cm->visible and !has_capability('moodle/course:viewhiddenactivities', $context)){
 271         if (!empty($CFG->search_access_debug)) echo "search reject : hidden chat ";
 272         return false;
 273     }
 274
 275     //group consistency check : checks the following situations about groups
 276     // trap if user is not same group and groups are separated
 277     $course = get_record('course', 'id', $chat->course);
 278     if ((groupmode($course, $cm) == SEPARATEGROUPS) && !ismember($group_id) && !has_capability('moodle/site:accessallgroups', $context)){
 279         if (!empty($CFG->search_access_debug)) echo "search reject : chat element is in separated group ";
 280         return false;
 281     }
 282
 283     //ownership check : checks the following situations about user
 284     // trap if user is not owner and has cannot see other's entries
 285     // TODO : typically may be stored into indexing cache
 286     if (!has_capability('mod/chat:readlog', $context)){
 287         if (!empty($CFG->search_access_debug)) echo "search reject : cannot read past sessions ";
 288         return false;
 289     }
 290
 291     return true;
 292 }
 293
 294 /**
 295 * this call back is called when displaying the link for some last post processing
 296 *
 297 */
 298 function chat_link_post_processing($title){
 299     global $CFG;
 300     setLocale(LC_TIME, substr(current_language(), 0, 2));
 301     $title = preg_replace('/TT_(.*)_TT/e', "userdate(\\1)", $title);
 302
 303     if ($CFG->block_search_utf8dir){
 304         return mb_convert_encoding($title, 'UTF-8', 'auto');
 305     }
 306     return mb_convert_encoding($title, 'auto', 'UTF-8');
 307 }
 308 ?>