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Public Member Functions | Static Public Member Functions
ilChangeEvent Class Reference

Class ilChangeEvent tracks change events on repository objects. More...

+ Collaboration diagram for ilChangeEvent:

Public Member Functions

 _recordWriteEvent ($obj_id, $usr_id, $action, $parent_obj_id=null)
 Records a write event.
 _recordReadEvent ($obj_id, $usr_id, $isCatchupWriteEvents=true)
 Records a read event and catches up with write events.
 _catchupWriteEvents ($obj_id, $usr_id, $timestamp=null)
 Catches up with all write events which occured before the specified timestamp.

Static Public Member Functions

static _lookupUncaughtWriteEvents ($obj_id, $usr_id)
 Catches up with all write events which occured before the specified timestamp.
static _lookupChangeState ($obj_id, $usr_id)
 Returns the change state of the object for the specified user.
static _lookupInsideChangeState ($parent_obj_id, $usr_id)
 Returns the changed state of objects which are children of the specified parent object.
static _lookupReadEvents ($obj_id, $usr_id=null)
 Reads all read events which occured on the object which happened after the last time the user caught up with them.
static _activate ()
 Activates change event tracking.
static _deactivate ()
 Deactivates change event tracking.
static _isActive ()
 Returns true, if change event tracking is active.

Detailed Description

Class ilChangeEvent tracks change events on repository objects.

The following events are considered to be a 'write event':

  • The creation of a new repository object
  • A change of the data or meta-data of an object
  • A move, link, copy, deletion or undeletion of the object UI objects, which cause a 'write event', must call _recordWriteEvent(...) In most cases, UI objects let the user catch up with write events on the object, when doing this call.

The following events are considered to be a 'read event':

  • Opening a container object in the browser*
  • Opening / downloading / reading an object UI objects, which cause a 'read event', must call _recordReadEvent(...). In most cases, UI objects let the user catch up with write events on the object, when doing this call.

*reading the content of a container using WebDAV is not counted, because WebDAV clients can't see all objects in a container.

A user can catch up with write events, by calling __catchupWriteEvents(...).

A user can query, if an object has changed, since the last time he has caught up with write events, by calling _lookupUncaughtWriteEvents(...).

Author
Werner Randelshofer werne.nosp@m.r.ra.nosp@m.ndels.nosp@m.hofe.nosp@m.r@hsl.nosp@m.u.ch
Version
Id:
class.ilChangeEvent.php,v 1.02 2007/05/07 19:25:34 wrandels Exp

Definition at line 55 of file class.ilChangeEvent.php.

Member Function Documentation

static ilChangeEvent::_activate ( )
static

Activates change event tracking.

Returns
mixed true on success, a string with an error message on failure.

Definition at line 421 of file class.ilChangeEvent.php.

References _isActive().

Referenced by ilObjUserTracking\updateSettings().

{
if (ilChangeEvent::_isActive())
{
return 'change event tracking is already active';
}
else
{
global $ilDB;
// Insert initial data into table write_event
// We need to do this here, because we need
// to catch up write events that occured while the change event tracking was
// deactivated.
$q = "INSERT IGNORE INTO write_event ".
"(obj_id,parent_obj_id,usr_id,action,ts) ".
"SELECT r1.obj_id,r2.obj_id,d.owner,'create',d.create_date ".
"FROM object_data AS d ".
"JOIN object_reference AS r1 ON d.obj_id=r1.obj_id ".
"JOIN tree AS t ON t.child=r1.ref_id ".
"JOIN object_reference as r2 on r2.ref_id=t.parent ";
$r = $ilDB->db->query($q);
if ($ilDB->isError($r) || $ilDB->isError($r->result))
{
return 'couldn\'t insert initial data into table "write_event": '.
(($ilDB->isError($r->result)) ? $r->result->getMessage() : $r->getMessage());
}
global $ilias;
$ilias->setSetting('enable_change_event_tracking', '1');
return true;
}
}

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ilChangeEvent::_catchupWriteEvents (   $obj_id,
  $usr_id,
  $timestamp = null 
)

Catches up with all write events which occured before the specified timestamp.

Parameters
$obj_idint The object.
$usr_idint The user.
$timestampSQL timestamp.

Definition at line 154 of file class.ilChangeEvent.php.

References $timestamp.

Referenced by _recordReadEvent(), ilContainerGUI\pasteObject(), ilDAVServer\PUT(), ilObjectGUI\undeleteObject(), ilObjFolderGUI\updateObject(), ilObjGroupGUI\updateObject(), ilObjFileGUI\updateObject(), ilObjCategoryGUI\updateObject(), and ilObjCourseGUI\updateObject().

{
global $ilDB;
$q = "INSERT INTO catch_write_events ".
"(obj_id, usr_id, ts) ".
"VALUES (".
$ilDB->quote($obj_id).",".
$ilDB->quote($usr_id).",";
if ($timestamp == null)
{
$q .= "NOW()".
") ON DUPLICATE KEY UPDATE ts=NOW()";
}
else {
$q .= $ilDB->quote($timestamp).
") ON DUPLICATE KEY UPDATE ts=".$ilDB->quote($timestamp);
}
//error_log ('ilChangeEvent::_catchupWriteEvents '.$q);
$r = $ilDB->query($q);
}

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static ilChangeEvent::_deactivate ( )
static

Deactivates change event tracking.

Returns
mixed true on success, a string with an error message on failure.

Definition at line 461 of file class.ilChangeEvent.php.

Referenced by ilObjUserTracking\updateSettings().

{
global $ilias;
$ilias->setSetting('enable_change_event_tracking', '0');
}

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static ilChangeEvent::_isActive ( )
static

Returns true, if change event tracking is active.

Returns
mixed true on success, a string with an error message on failure.

Definition at line 472 of file class.ilChangeEvent.php.

Referenced by ilObjUserTracking\__readSettings(), _activate(), ilInfoScreenGUI\addObjectSections(), ilDAVServer\COPY(), ilDAVServer\DELETE(), ilDAVServer\GET(), ilObjectListGUI\getProperties(), ilDAVServer\MKCOL(), ilDAVServer\MOVE(), ilContainerGUI\pasteObject(), ilDAVServer\PROPFIND(), ilDAVServer\PUT(), ilObjectGUI\removeFromSystemObject(), ilObjFolderGUI\saveObject(), ilObjGroupGUI\saveObject(), ilObjFileGUI\saveObject(), ilObjCategoryGUI\saveObject(), ilObjCourseGUI\saveObject(), ilObjFileGUI\sendFileObject(), ilContainerContentGUI\setOutput(), ilObjectGUI\undeleteObject(), ilObjFolderGUI\updateObject(), ilObjGroupGUI\updateObject(), ilObjFileGUI\updateObject(), ilObjCategoryGUI\updateObject(), ilObjCourseGUI\updateObject(), ilObjUserTracking\updateSettings(), ilCourseContentGUI\view(), and ilObjectGUI\viewObject().

{
global $ilias;
return $ilias->getSetting('enable_change_event_tracking', '0') == '1';
}

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static ilChangeEvent::_lookupChangeState (   $obj_id,
  $usr_id 
)
static

Returns the change state of the object for the specified user.

which happened after the last time the user caught up with them.

Parameters
$obj_idint The object
$usr_idint The user who is interested into these events.
Returns
0 = object is unchanged, 1 = object is new, 2 = object has changed

Definition at line 261 of file class.ilChangeEvent.php.

References DB_FETCHMODE_ASSOC.

Referenced by ilObjectListGUI\getProperties().

{
global $ilDB;
$q = "SELECT ts ".
"FROM catch_write_events ".
"WHERE obj_id=".$ilDB->quote($obj_id)." ".
"AND usr_id=".$ilDB->quote($usr_id);
$r = $ilDB->query($q);
$catchup = null;
while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC)) {
$catchup = $row['ts'];
}
$q = "SELECT * ".
"FROM write_event ".
"WHERE obj_id=".$ilDB->quote($obj_id)." ".
"AND usr_id <> ".$ilDB->quote($usr_id)." ".
($catchup == null ? "" : "AND ts > ".$ilDB->quote($catchup))." ".
//"ORDER BY ts DESC ". --> Note: to improve performance we don't need order by here
"LIMIT 1";
$r = $ilDB->query($q);
$numRows = $r->numRows();
if ($numRows > 0)
{
$row = $r->fetchRow(DB_FETCHMODE_ASSOC);
// if we have write events, and user never catched one, report as new (1)
// if we have write events, and user catched an old write event, report as changed (2)
return ($catchup == null) ? 1 : 2;
}
else
{
return 0; // user catched all write events, report as unchanged (0)
}
}

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static ilChangeEvent::_lookupInsideChangeState (   $parent_obj_id,
  $usr_id 
)
static

Returns the changed state of objects which are children of the specified parent object.

Note this gives a different result than calling _lookupChangeState of each child object. This is because, this function treats a catch on the write events on the parent as a catch up for all child objects. This difference was made, because it greatly improves performance of this function.

Parameters
$parent_obj_idint The object id of the parent object.
$usr_idint The user who is interested into these events.
Returns
0 = object has not been changed inside 1 = object has been changed inside

Definition at line 310 of file class.ilChangeEvent.php.

References DB_FETCHMODE_ASSOC.

Referenced by ilObjectListGUI\getProperties().

{
global $ilDB;
$q = "SELECT ts ".
"FROM catch_write_events ".
"WHERE obj_id=".$ilDB->quote($parent_obj_id)." ".
"AND usr_id=".$ilDB->quote($usr_id);
$r = $ilDB->query($q);
$catchup = null;
while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC)) {
$catchup = $row['ts'];
}
$q = "SELECT * ".
"FROM write_event ".
"WHERE parent_obj_id=".$ilDB->quote($parent_obj_id)." ".
"AND usr_id <> ".$ilDB->quote($usr_id)." ".
($catchup == null ? "" : "AND ts > ".$ilDB->quote($catchup))." ".
//"ORDER BY ts DESC ". --> Note: to improve performance we don't need order by here
"LIMIT 1";
$r = $ilDB->query($q);
$numRows = $r->numRows();
if ($numRows > 0)
{
$row = $r->fetchRow(DB_FETCHMODE_ASSOC);
// if we have write events, and user never catched one, report as new (1)
// if we have write events, and user catched an old write event, report as changed (2)
return ($catchup == null) ? 1 : 2;
}
else
{
return 0; // user catched all write events, report as unchanged (0)
}
}

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static ilChangeEvent::_lookupReadEvents (   $obj_id,
  $usr_id = null 
)
static

Reads all read events which occured on the object which happened after the last time the user caught up with them.

NOTE: THIS FUNCTION NEEDS TO BE REWRITTEN. READ EVENTS ARE OF INTEREST AT REF_ID's OF OBJECTS.

Parameters
$obj_idint The object
$usr_idint The user who is interested into these events. / public static function _lookupUncaughtReadEvents($obj_id, $usr_id) { global $ilDB;

$q = "SELECT ts ". "FROM catch_read_events ". "WHERE obj_id=".$ilDB->quote($obj_id)." ". "AND usr_id=".$ilDB->quote($usr_id); $r = $ilDB->query($q); $catchup = null; while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC)) { $catchup = $row['ts']; }

$q = "SELECT * ". "FROM read_event ". "WHERE obj_id=".$ilDB->quote($obj_id)." ". ($catchup == null ? "" : "AND last_access > ".$ilDB->quote($catchup))." ". ($catchup == null ? "" : "AND last_access > ".$ilDB->quote($catchup))." ". "ORDER BY last_access DESC"; $r = $ilDB->query($q); $events = array(); while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC)) { $events[] = $row; } return $events; } Reads all read events which occured on the object.

Parameters
$obj_idint The object
$usr_idint Optional, the user who performed these events.

Definition at line 388 of file class.ilChangeEvent.php.

References DB_FETCHMODE_ASSOC.

Referenced by ilLearningProgress\_getProgress(), ilLearningProgress\_lookupProgressByObjId(), and ilInfoScreenGUI\addObjectSections().

{
global $ilDB;
if ($usr_id == null)
{
$q = "SELECT * ".
"FROM read_event ".
"WHERE obj_id=".$ilDB->quote($obj_id)." ".
"ORDER BY last_access DESC";
}
else
{
$q = "SELECT * ".
"FROM read_event ".
"WHERE obj_id=".$ilDB->quote($obj_id)." ".
"AND usr_id=".$ilDB->quote($usr_id)." ".
"ORDER BY last_access DESC";
}
$r = $ilDB->query($q);
$events = array();
while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC))
{
$events[] = $row;
}
return $events;
}

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static ilChangeEvent::_lookupUncaughtWriteEvents (   $obj_id,
  $usr_id 
)
static

Catches up with all write events which occured before the specified timestamp.

THIS FUNCTION IS CURRENTLY NOT IN USE. BEFORE IT CAN BE USED, THE TABLE catch_read_events MUST BE CREATED.

Parameters
$obj_idint The object.
$usr_idint The user.
$timestampSQL timestamp. / function _catchupReadEvents($obj_id, $usr_id, $timestamp = null) { global $ilDB;

$q = "INSERT INTO catch_read_events ". "(obj_id, usr_id, action, ts) ". "VALUES (". $ilDB->quote($obj_id).",". $ilDB->quote($usr_id).",". $ilDB->quote('read').","; if ($timestamp == null) { $q .= "NOW()". ") ON DUPLICATE KEY UPDATE ts=NOW()"; } else { $q .= $ilDB->quote($timestamp). ") ON DUPLICATE KEY UPDATE ts=".$ilDB->quote($timestamp); }

$r = $ilDB->query($q); } Reads all write events which occured on the object which happened after the last time the user caught up with them.

Parameters
$obj_idint The object
$usr_idint The user who is interested into these events.
Returns
array with rows from table write_event

Definition at line 223 of file class.ilChangeEvent.php.

References DB_FETCHMODE_ASSOC.

{
global $ilDB;
$q = "SELECT ts ".
"FROM catch_write_events ".
"WHERE obj_id=".$ilDB->quote($obj_id)." ".
"AND usr_id=".$ilDB->quote($usr_id);
$r = $ilDB->query($q);
$catchup = null;
while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC)) {
$catchup = $row['ts'];
}
$q = "SELECT * ".
"FROM write_event ".
"WHERE obj_id=".$ilDB->quote($obj_id)." ".
"AND usr_id <> ".$ilDB->quote($usr_id)." ".
($catchup == null ? "" : "AND ts > ".$ilDB->quote($catchup))." ".
"ORDER BY ts DESC";
$r = $ilDB->query($q);
$events = array();
while ($row = $r->fetchRow(DB_FETCHMODE_ASSOC))
{
$events[] = $row;
}
return $events;
}
ilChangeEvent::_recordReadEvent (   $obj_id,
  $usr_id,
  $isCatchupWriteEvents = true 
)

Records a read event and catches up with write events.

Parameters
$obj_idint The object which was read.
$usr_idint The user who performed a read action.
$catchupWriteEventsboolean If true, this function catches up with write events.

Definition at line 115 of file class.ilChangeEvent.php.

References _catchupWriteEvents(), and ilObjUserTracking\_getValidTimeSpan().

Referenced by ilLearningProgress\_tracProgress(), ilLearningProgress\_updateProgress(), ilDAVServer\COPY(), ilDAVServer\GET(), ilContainerGUI\pasteObject(), ilDAVServer\PROPFIND(), ilObjFileGUI\sendFileObject(), ilContainerContentGUI\setOutput(), ilCourseContentGUI\view(), and ilObjectGUI\viewObject().

{
global $ilDB;
include_once('Services/Tracking/classes/class.ilObjUserTracking.php');
$validTimeSpan = ilObjUserTracking::_getValidTimeSpan();
// Important: In the SQL statement below, it is important that ts
// is updated after spent_seconds is updated, because
// spent_seconds computes its value from the old value of ts.
$q = "INSERT INTO read_event ".
"(obj_id, usr_id, first_access, last_access, read_count) ".
"VALUES (".
$ilDB->quote($obj_id).",".
$ilDB->quote($usr_id).",".
"NOW(), NOW(), 1".
") ".
"ON DUPLICATE KEY ".
"UPDATE ".
"read_count=read_count+1, ".
"spent_seconds = IF (TIME_TO_SEC(TIMEDIFF(NOW(),last_access))<=".$ilDB->quote($validTimeSpan).",spent_seconds+TIME_TO_SEC(TIMEDIFF(NOW(),last_access)),spent_seconds),".
"last_access=NOW()".
"";
$r = $ilDB->query($q);
//error_log ('ilChangeEvent::_recordReadEvent '.$q);
if ($isCatchupWriteEvents)
{
ilChangeEvent::_catchupWriteEvents($obj_id, $usr_id);
}
}

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ilChangeEvent::_recordWriteEvent (   $obj_id,
  $usr_id,
  $action,
  $parent_obj_id = null 
)

Records a write event.

The parent object should be specified for the 'delete', 'undelete' and 'add' and 'remove' events.

Parameters
$obj_idint The object which was written to.
$usr_idint The user who performed a write action.
$actionstring The name of the write action. 'create', 'update', 'delete', 'add', 'remove', 'undelete'.
$parent_obj_idint The object id of the parent object. If this is null, then the event is recorded for all parents of the object. If this is not null, then the event is only recorded for the specified parent.

Definition at line 72 of file class.ilChangeEvent.php.

Referenced by ilDAVServer\COPY(), ilDAVServer\DELETE(), ilDAVServer\MKCOL(), ilDAVServer\MOVE(), ilContainerGUI\pasteObject(), ilDAVServer\PUT(), ilObjectGUI\removeFromSystemObject(), ilObjFolderGUI\saveObject(), ilObjGroupGUI\saveObject(), ilObjFileGUI\saveObject(), ilObjCategoryGUI\saveObject(), ilObjCourseGUI\saveObject(), ilObjectGUI\undeleteObject(), ilObjFolderGUI\updateObject(), ilObjGroupGUI\updateObject(), ilObjFileGUI\updateObject(), ilObjCategoryGUI\updateObject(), and ilObjCourseGUI\updateObject().

{
global $ilDB;
if ($parent_obj_id == null)
{
$q = "INSERT IGNORE INTO write_event ".
"(obj_id, parent_obj_id, usr_id, action, ts) ".
"SELECT ".
$ilDB->quote($obj_id).",".
"r2.obj_id,".
$ilDB->quote($usr_id).",".
$ilDB->quote($action).",".
"NOW() ".
"FROM object_reference AS r1 ".
"JOIN tree AS t ON t.child = r1.ref_id ".
"JOIN object_reference AS r2 ON r2.ref_id = t.parent ".
"WHERE r1.obj_id = ".$ilDB->quote($obj_id);
}
else
{
$q = "INSERT IGNORE INTO write_event ".
"(obj_id, parent_obj_id, usr_id, action, ts) ".
"VALUES (".
$ilDB->quote($obj_id).",".
$ilDB->quote($parent_obj_id).",".
$ilDB->quote($usr_id).",".
$ilDB->quote($action).",".
"NOW()".
")";
}
$r = $ilDB->query($q);
//error_log ('ilChangeEvent::_recordWriteEvent '.$q);
}

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The documentation for this class was generated from the following file: