/**
* update surfer presence
*
* This function is used to track presence information.
* Errors are not reported, if any
*
* @param string web address of visited page
* @param string related title
* @param string the target anchor, if any
* @param string level of visibility for this anchor (e.g., 'Y', 'R' or 'N')
*/
public static function is_visiting($link, $label, $anchor = NULL, $active = 'Y')
{
global $context;
// don't track crawlers
if (Surfer::is_crawler()) {
return;
}
// update the history stack
if (!isset($context['pages_without_history']) || $context['pages_without_history'] != 'Y') {
// put at top of stack
if (!isset($_SESSION['visited'])) {
$_SESSION['visited'] = array();
}
$_SESSION['visited'] = array_merge(array($link => $label), $_SESSION['visited']);
// limit to 20 most recent pages
if (count($_SESSION['visited']) > 20) {
array_pop($_SESSION['visited']);
}
}
// no anchor to remember
if (!$anchor) {
return;
}
// ensure regular operation of the server
if (!file_exists($context['path_to_root'] . 'parameters/switch.on')) {
return;
}
// nothing remembered for anonymous surfers
if (!Surfer::get_id()) {
return;
}
// we need a GET
if (!isset($_SERVER['REQUEST_METHOD']) || $_SERVER['REQUEST_METHOD'] != 'GET') {
return;
}
// Firefox pre-fetch is not a real visit
if (isset($_SERVER['HTTP_X_MOZ']) && $_SERVER['HTTP_X_MOZ'] == 'prefetch') {
return;
}
// ensure the back-end is there
if (!is_callable(array('SQL', 'query'))) {
return;
}
// update the record of the surfer
$query = "UPDATE " . SQL::table_name('users') . " SET click_anchor='" . SQL::escape($anchor) . "', click_date='" . gmstrftime('%Y-%m-%d %H:%M:%S') . "'" . " WHERE id = " . SQL::escape(Surfer::get_id());
SQL::query($query, FALSE, $context['users_connection']);
// also update recent visits
include_once $context['path_to_root'] . 'users/visits.php';
Visits::track($anchor, $active);
// job done
return;
}
// get the related anchor, if any
if ($anchor) {
$anchor = Anchors::get($anchor);
}
// required to format the roster
load_skin('users');
// stop crawlers
if (Surfer::is_crawler()) {
Safe::header('Status: 401 Unauthorized', TRUE, 401);
Logger::error(i18n::s('You are not allowed to perform this operation.'));
// an anchor is mandatory
} elseif (!is_object($anchor)) {
Safe::header('Status: 404 Not Found', TRUE, 404);
die(i18n::s('No anchor has been found.'));
// provide updated information for this anchor
} else {
// silently record this visit
Visits::track($anchor->get_reference(), $anchor->get_active());
// return an updated list of current visitors, to be used in AJAX
$output = Visits::list_users_at_anchor($anchor->get_reference());
// ensure we are producing some text -- open links in separate pages
if (is_array($output)) {
$output =& Skin::build_list($output, 'compact', NULL, TRUE);
}
// actual transmission except on a HEAD request
if (isset($_SERVER['REQUEST_METHOD']) && $_SERVER['REQUEST_METHOD'] != 'HEAD') {
echo $output;
}
// the post-processing hook, then exit
finalize_page(TRUE);
}
