search/documents/chat_document.php

   1 <?php
   2 /**
   3 * Global Search Engine for Moodle
   4 * add-on 1.8+ : Valery Fremaux [valery.fremaux@club-internet.fr]
   5 * 2007/08/02
   6 *
   7 * document handling for chat activity module
   8 * This file contains the mapping between a chat history and it's indexable counterpart,
   9 *
  10 * Functions for iterating and retrieving the necessary records are now also included
  11 * in this file, rather than mod/chat/lib.php
  12 **/
  13
  14 require_once("$CFG->dirroot/search/documents/document.php");
  15 require_once("$CFG->dirroot/mod/chat/lib.php");
  16
  17 /*
  18 * a class for representing searchable information
  19 *
  20 **/
  21 class ChatTrackSearchDocument extends SearchDocument {
  22
  23     /**
  24     * constructor
  25     *
  26     */
  27     public function __construct(&$chatsession, $chat_module_id, $course_id, $group_id, $context_id) {
  28         // generic information; required
  29         $doc->docid         = $chat_module_id.'-'.$chatsession['sessionstart'].'-'.$chatsession['sessionend'];
  30         $doc->documenttype  = SEARCH_TYPE_CHAT;
  31         $doc->itemtype      = 'session';
  32         $doc->contextid     = $context_id;
  33
  34         $duration           = $chatsession['sessionend'] - $chatsession['sessionstart'];
  35         // we cannot call userdate with relevant locale at indexing time.
  36         $doc->title         = get_string('chatreport', 'chat').' '.get_string('openedon', 'search').' TT_'.$chatsession['sessionstart'].'_TT ('.get_string('duration', 'search').' : '.get_string('numseconds', '', $duration).')';
  37         $doc->date          = $chatsession['sessionend'];
  38
  39         //remove '(ip.ip.ip.ip)' from chat author list
  40         $doc->author        = preg_replace('/\(.*?\)/', '', $chatsession['authors']);
  41         $doc->contents      = $chatsession['content'];
  42         $doc->url           = chat_make_link($chat_module_id, $chatsession['sessionstart'], $chatsession['sessionend']);
  43
  44         // module specific information; optional
  45         $data->chat         = $chat_module_id;
  46
  47         // construct the parent class
  48         parent::__construct($doc, $data, $course_id, $group_id, 0, PATH_FOR_SEARCH_TYPE_CHAT);
  49     } //constructor
  50 } //ChatTrackSearchDocument
  51
  52
  53 /**
  54 * constructs a valid link to a chat content
  55 * @param cm_id the chat course module
  56 * @param start the start time of the session
  57 * @param end th end time of the session
  58 * @return a well formed link to session display
  59 */
  60 function chat_make_link($cm_id, $start, $end) {
  61     global $CFG;
  62
  63     return $CFG->wwwroot.'/mod/chat/report.php?id='.$cm_id.'&amp;start='.$start.'&amp;end='.$end;
  64 } //chat_make_link
  65
  66 /**
  67 * fetches all the records for a given session and assemble them as a unique track
  68 * we revamped here the code of report.php for making sessions, but without any output.
  69 * note that we should collect sessions "by groups" if groupmode() is SEPARATEGROUPS.
  70 * @param chat_id the database
  71 * @return an array of objects representing the chat sessions.
  72 */
  73 function chat_get_session_tracks($chat_id, $fromtime = 0, $totime = 0) {
  74     global $CFG;
  75
  76     $chat = get_record('chat', 'id', $chat_id);
  77     $course = get_record('course', 'id', $chat->course);
  78     $coursemodule = get_field('modules', 'id', 'name', 'data');
  79     $cm = get_record('course_modules', 'course', $course->id, 'module', $coursemodule, 'instance', $chat->id);
  80     $groupmode = groupmode($course, $cm);
  81
  82     $fromtimeclause = ($fromtime) ? "AND timestamp >= {$fromtime}" : '';
  83     $totimeclause = ($totime) ? "AND timestamp <= {$totime}" : '';
  84     $tracks = array();
  85     $messages = get_records_select('chat_messages', "chatid = '{$chat_id}' $fromtimeclause $totimeclause", "timestamp DESC");
  86     if ($messages){
  87         // splits discussions against groups
  88         $groupedMessages = array();
  89         if ($groupmode != SEPARATEGROUPS){
  90             foreach($messages as $aMessage){
  91                 $groupedMessages[$aMessage->groupid][] = $aMessage;
  92             }
  93         }
  94         else{
  95             $groupedMessages[-1] = &$messages;
  96         }
  97         $sessiongap = 5 * 60;    // 5 minutes silence means a new session
  98         $sessionend = 0;
  99         $sessionstart = 0;
 100         $sessionusers = array();
 101         $lasttime = time();
 102
 103         foreach ($groupedMessages as $groupId => $messages) {  // We are walking BACKWARDS through the messages
 104             $messagesleft = count($messages);
 105             foreach ($messages as $message) {  // We are walking BACKWARDS through the messages
 106                 $messagesleft --;              // Countdown
 107
 108                 if ($message->system) {
 109                     continue;
 110                 }
 111                 // we are within a session track
 112                 if ((($lasttime - $message->timestamp) < $sessiongap) and $messagesleft) {  // Same session
 113                     if (count($tracks) > 0){
 114                         if ($message->userid) {       // Remember user and count messages
 115                             $tracks[count($tracks) - 1]->sessionusers[$message->userid] = $message->userid;
 116                             // update last track (if exists) record appending content (remember : we go backwards)
 117                         }
 118                         $tracks[count($tracks) - 1]->content .= ' '.$message->message;
 119                         $tracks[count($tracks) - 1]->sessionstart = $message->timestamp;
 120                     }
 121                 }
 122                 // we initiate a new session track (backwards)
 123                 else {
 124                     $track = new Object();
 125                     $track->sessionend = $message->timestamp;
 126                     $track->sessionstart = $message->timestamp;
 127                     $track->content = $message->message;
 128                     // reset the accumulator of users
 129                     $track->sessionusers = array();
 130                     $track->sessionusers[$message->userid] = $message->userid;
 131                     $track->groupid = $groupId;
 132                     $tracks[] = $track;
 133                 }
 134                 $lasttime = $message->timestamp;
 135             }
 136         }
 137     }
 138     return $tracks;
 139 } //chat_get_session_tracks
 140
 141 /**
 142 * part of search engine API
 143 *
 144 */
 145 function chat_iterator() {
 146     $chatrooms = get_records('chat');
 147     return $chatrooms;
 148 } //chat_iterator
 149
 150 /**
 151 * part of search engine API
 152 *
 153 */
 154 function chat_get_content_for_index(&$chat) {
 155     $documents = array();
 156     $course = get_record('course', 'id', $chat->course);
 157     $coursemodule = get_field('modules', 'id', 'name', 'chat');
 158     $cm = get_record('course_modules', 'course', $course->id, 'module', $coursemodule, 'instance', $chat->id);
 159     $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 160
 161     // getting records for indexing
 162     $sessionTracks = chat_get_session_tracks($chat->id);
 163     if ($sessionTracks){
 164         foreach($sessionTracks as $aTrackId => $aTrack) {
 165             foreach($aTrack->sessionusers as $aUserId){
 166                 $user = get_record('user', 'id', $aUserId);
 167                 $aTrack->authors = ($user) ? $user->firstname.' '.$user->lastname : '' ;
 168                 $documents[] = new ChatTrackSearchDocument(get_object_vars($aTrack), $cm->id, $chat->course, $aTrack->groupid, $context->id);
 169             }
 170         }
 171     }
 172     return $documents;
 173 } //chat_get_content_for_index
 174
 175 /**
 176 * returns a single data search document based on a chat_session id
 177 * chat session id is a text composite identifier made of :
 178 * - the chat id
 179 * - the timestamp when the session starts
 180 * - the timestamp when the session ends
 181 * @param id the multipart chat session id
 182 * @param itemtype the type of information (session is the only type)
 183 */
 184 function chat_single_document($id, $itemtype) {
 185     list($chat_id, $sessionstart, $sessionend) = split('-', $id);
 186     $chat = get_record('chat', 'id', $chat_id);
 187     $course = get_record('course', 'id', $chat->course);
 188     $coursemodule = get_field('modules', 'id', 'name', 'chat');
 189     $cm = get_record('course_modules', 'course', $course->id, 'module', $coursemodule, 'instance', $chat->id);
 190     $context = get_context_instance(CONTEXT_MODULE, $cm->id);
 191
 192     // should be only one
 193     $tracks = chat_get_session_tracks($chat->id, $sessionstart, $sessionstart);
 194     if ($tracks){
 195         $aTrack = $tracks[0];
 196         $documents[] = new ChatTrackSearchDocument(get_object_vars($aTrack), $cm->id, $chat->course, $aTrack->groupid, $context->id);
 197     }
 198 } //chat_single_document
 199
 200 /**
 201 * dummy delete function that packs id with itemtype.
 202 * this was here for a reason, but I can't remember it at the moment.
 203 *
 204 */
 205 function chat_delete($info, $itemtype) {
 206     $object->id = $info;
 207     $object->itemtype = $itemtype;
 208     return $object;
 209 } //chat_delete
 210
 211 /**
 212 * returns the var names needed to build a sql query for addition/deletions
 213 * // TODO chat indexable records are virtual. Should proceed in a special way
 214 */
 215 function chat_db_names() {
 216     //[primary id], [table name], [time created field name], [time modified field name]
 217     return null;
 218 } //chat_db_names
 219
 220 /**
 221 * this function handles the access policy to contents indexed as searchable documents. If this
 222 * function does not exist, the search engine assumes access is allowed.
 223 * When this point is reached, we already know that :
 224 * - user is legitimate in the surrounding context
 225 * - user may be guest and guest access is allowed to the module
 226 * - the function may perform local checks within the module information logic
 227 * @param path the access path to the module script code
 228 * @param itemtype the information subclassing (usefull for complex modules, defaults to 'standard')
 229 * @param this_id the item id within the information class denoted by entry_type. In chats, this id
 230 * points out a session history which is a close sequence of messages.
 231 * @param user the user record denoting the user who searches
 232 * @param group_id the current group used by the user when searching
 233 * @return true if access is allowed, false elsewhere
 234 */
 235 function chat_check_text_access($path, $itemtype, $this_id, $user, $group_id, $context_id){
 236     global $CFG;
 237
 238     include_once("{$CFG->dirroot}/{$path}/lib.php");
 239
 240     list($chat_id, $sessionstart, $sessionend) = split('-', $id);
 241
 242     // get the chat session and all related stuff
 243     $chat = get_record('chat', 'id', $chat_id);
 244     $course = get_record('course', 'id', $chat->course);
 245     $module_context = get_record('context', 'id', $context_id);
 246     $cm = get_record('course_modules', 'id', $module_context->instanceid);
 247     if (!$cm->visible and !has_capability('moodle/course:viewhiddenactivities', $module_context)) return false;
 248
 249     //group consistency check : checks the following situations about groups
 250     // trap if user is not same group and groups are separated
 251     $current_group = get_current_group($course->id);
 252     if ((groupmode($course) == SEPARATEGROUPS) && !ismember($group_id) && !has_capability('moodle/site:accessallgroups', $module_context)) return false;
 253
 254     //ownership check : checks the following situations about user
 255     // trap if user is not owner and has cannot see other's entries
 256     // TODO : typically may be stored into indexing cache
 257     if (!has_capability('mod/chat:readlog', $module_context)) return false;
 258
 259     return true;
 260 } //chat_check_text_access
 261
 262 /**
 263 * this call back is called when displaying the link for some last post processing
 264 *
 265 */
 266 function chat_link_post_processing($title){
 267      setLocale(LC_TIME, substr(current_language(), 0, 2));
 268      $title = preg_replace('/TT_(.*)_TT/e', "userdate(\\1)", $title);
 269      return $title;
 270 } //chat_link_post_processing
 271 ?>