mirror of
https://github.com/moodle/moodle.git
synced 2025-01-18 22:08:20 +01:00
531 lines
17 KiB
PHP
531 lines
17 KiB
PHP
<?php //$Id$
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/**
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* Factory method returning moodle_session object.
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* @return moodle_session
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*/
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function session_get_instance() {
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static $session = null;
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if (is_null($session)) {
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$session = new moodle_session();
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}
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return $session;
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}
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/**
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* Class handling all session and cookies related stuff.
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*/
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class moodle_session {
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public function __construct() {
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global $CFG;
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$this->prepare_cookies();
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$this->init_session_storage();
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if (!empty($CFG->usesid) && empty($_COOKIE['MoodleSession'.$CFG->sessioncookie])) {
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sid_start_ob();
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}
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if (NO_MOODLE_COOKIES) {
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$_SESSION = array();
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$_SESSION['SESSION'] = new object();
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$_SESSION['USER'] = new object();
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} else {
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session_name('MoodleSession'.$CFG->sessioncookie);
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session_set_cookie_params(0, $CFG->sessioncookiepath, $CFG->sessioncookiedomain, $CFG->cookiesecure, $CFG->cookiehttponly);
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@session_start();
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if (!isset($_SESSION['SESSION'])) {
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$_SESSION['SESSION'] = new object();
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}
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if (!isset($_SESSION['USER'])) {
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$_SESSION['USER'] = new object();
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}
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}
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$this->check_user_initialised();
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$this->check_security();
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}
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/**
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* Initialise $USER object, handles google access.
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*
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* @return void
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*/
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protected function check_user_initialised() {
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if (isset($_SESSION['USER']->id)) {
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// already set up $USER
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return;
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}
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$user = null;
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if (!empty($CFG->opentogoogle) and !NO_MOODLE_COOKIES) {
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if (!empty($_SERVER['HTTP_USER_AGENT'])) {
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// allow web spiders in as guest users
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if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
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$user = guest_user();
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} else if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) { // Google
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$user = guest_user();
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} else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yahoo! Slurp') !== false ) { // Yahoo
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$user = guest_user();
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} else if (strpos($_SERVER['HTTP_USER_AGENT'], '[ZSEBOT]') !== false ) { // Zoomspider
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$user = guest_user();
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} else if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSNBOT') !== false ) { // MSN Search
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$user = guest_user();
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}
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}
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if (!empty($CFG->guestloginbutton) and !$user and !empty($_SERVER['HTTP_REFERER'])) {
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// automaticaly log in users coming from search engine results
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if (strpos($_SERVER['HTTP_REFERER'], 'google') !== false ) {
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$user = guest_user();
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} else if (strpos($_SERVER['HTTP_REFERER'], 'altavista') !== false ) {
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$user = guest_user();
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}
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}
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}
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if (!$user) {
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$user = new object();
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$user->id = 0; // to enable proper function of $CFG->notloggedinroleid hack
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if (isset($CFG->mnet_localhost_id)) {
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$user->mnethostid = $CFG->mnet_localhost_id;
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}
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}
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session_set_user($user);
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}
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/**
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* Does various session security checks
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* @global void
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*/
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protected function check_security() {
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global $CFG;
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if (!empty($_SESSION['USER']->id) and !empty($CFG->tracksessionip)) {
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/// Make sure current IP matches the one for this session
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$remoteaddr = getremoteaddr();
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if (empty($_SESSION['USER']->sessionip)) {
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$_SESSION['USER']->sessionip = $remoteaddr;
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}
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if ($_SESSION['USER']->sessionip != $remoteaddr) {
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// this is a security feature - terminate the session in case of any doubt
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$this->terminate();
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print_error('sessionipnomatch2', 'error');
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}
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}
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// TODO: add wwwroot check here
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}
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/**
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* Terminates active moodle session
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*/
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public function terminate() {
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global $CFG, $SESSION, $USER;
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$_SESSION = array();
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$SESSION = new object();
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$USER = new object();
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$USER->id = 0;
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if (isset($CFG->mnet_localhost_id)) {
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$USER->mnethostid = $CFG->mnet_localhost_id;
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}
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// Initialize variable to pass-by-reference to headers_sent(&$file, &$line)
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$file = null;
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$line = null;
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if (headers_sent($file, $line)) {
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error_log('Can not terminate session properly - headers were already sent in file: '.$file.' on line '.$line);
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}
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// now let's try to get a new session id and destroy the old one
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@session_regenerate_id(true);
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// close the session
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@session_write_close();
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}
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/**
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* Prepare cookies and varions system settings
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*/
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protected function prepare_cookies() {
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global $CFG, $nomoodlecookie;
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if (!defined('NO_MOODLE_COOKIES')) {
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if (isset($nomoodlecookie)) {
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// backwards compatibility only
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define('NO_MOODLE_COOKIES', $nomoodlecookie);
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unset($nomoodlecookie);
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} else {
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define('NO_MOODLE_COOKIES', false);
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}
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}
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if (!isset($CFG->cookiesecure) or strpos($CFG->wwwroot, 'https://') !== 0) {
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$CFG->cookiesecure = 0;
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}
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if (!isset($CFG->cookiehttponly)) {
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$CFG->cookiehttponly = 0;
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}
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/// Set sessioncookie and sessioncookiepath variable if it isn't already
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if (!isset($CFG->sessioncookie)) {
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$CFG->sessioncookie = '';
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}
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if (!isset($CFG->sessioncookiedomain)) {
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$CFG->sessioncookiedomain = '';
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}
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if (!isset($CFG->sessioncookiepath)) {
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$CFG->sessioncookiepath = '/';
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}
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//discard session ID from POST, GET and globals to tighten security,
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//this session fixation prevention can not be used in cookieless mode
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if (empty($CFG->usesid)) {
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unset(${'MoodleSession'.$CFG->sessioncookie});
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unset($_GET['MoodleSession'.$CFG->sessioncookie]);
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unset($_POST['MoodleSession'.$CFG->sessioncookie]);
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unset($_REQUEST['MoodleSession'.$CFG->sessioncookie]);
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}
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//compatibility hack for Moodle Cron, cookies not deleted, but set to "deleted" - should not be needed with NO_MOODLE_COOKIES in cron.php now
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if (!empty($_COOKIE['MoodleSession'.$CFG->sessioncookie]) && $_COOKIE['MoodleSession'.$CFG->sessioncookie] == "deleted") {
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unset($_COOKIE['MoodleSession'.$CFG->sessioncookie]);
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}
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}
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/**
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* Inits session storage.
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*/
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protected function init_session_storage() {
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global $CFG;
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/// Set up session handling
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if(empty($CFG->respectsessionsettings)) {
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if (true) { /// File-based sessions
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// Some distros disable GC by setting probability to 0
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// overriding the PHP default of 1
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// (gc_probability is divided by gc_divisor, which defaults to 1000)
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if (ini_get('session.gc_probability') == 0) {
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ini_set('session.gc_probability', 1);
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}
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if (!empty($CFG->sessiontimeout)) {
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ini_set('session.gc_maxlifetime', $CFG->sessiontimeout);
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}
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if (!file_exists($CFG->dataroot .'/sessions')) {
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make_upload_directory('sessions');
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}
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ini_set('session.save_path', $CFG->dataroot .'/sessions');
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} else { /// Database sessions
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// TODO: implement proper database session storage
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}
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}
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}
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}
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/**
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* Makes sure that $USER->sesskey exists, if $USER itself exists. It sets a new sesskey
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* if one does not already exist, but does not overwrite existing sesskeys. Returns the
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* sesskey string if $USER exists, or boolean false if not.
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*
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* @uses $USER
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* @return string
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*/
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function sesskey() {
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global $USER;
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if (empty($USER->sesskey)) {
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$USER->sesskey = random_string(10);
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}
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return $USER->sesskey;
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}
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/**
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* For security purposes, this function will check that the currently
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* given sesskey (passed as a parameter to the script or this function)
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* matches that of the current user.
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*
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* @param string $sesskey optionally provided sesskey
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* @return bool
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*/
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function confirm_sesskey($sesskey=NULL) {
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global $USER;
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if (!empty($USER->ignoresesskey)) {
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return true;
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}
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if (empty($sesskey)) {
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$sesskey = required_param('sesskey', PARAM_RAW); // Check script parameters
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}
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return (sesskey() === $sesskey);
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}
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/**
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* Sets a moodle cookie with a weakly encrypted string
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*
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* @uses $CFG
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* @uses DAYSECS
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* @uses HOURSECS
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* @param string $thing The string to encrypt and place in a cookie
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*/
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function set_moodle_cookie($thing) {
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global $CFG;
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if ($thing == 'guest') { // Ignore guest account
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return;
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}
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$cookiename = 'MOODLEID_'.$CFG->sessioncookie;
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$days = 60;
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$seconds = DAYSECS*$days;
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// no need to set secure or http cookie only here - it is not secret
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setcookie($cookiename, '', time() - HOURSECS, $CFG->sessioncookiepath, $CFG->sessioncookiedomain);
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setcookie($cookiename, rc4encrypt($thing), time()+$seconds, $CFG->sessioncookiepath, $CFG->sessioncookiedomain);
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}
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/**
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* Gets a moodle cookie with a weakly encrypted string
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*
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* @uses $CFG
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* @return string
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*/
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function get_moodle_cookie() {
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global $CFG;
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$cookiename = 'MOODLEID_'.$CFG->sessioncookie;
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if (empty($_COOKIE[$cookiename])) {
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return '';
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} else {
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$thing = rc4decrypt($_COOKIE[$cookiename]);
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return ($thing == 'guest') ? '': $thing; // Ignore guest account
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}
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}
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/**
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* Setup $USER object - called during login, loginas, etc.
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* Preloads capabilities and checks enrolment plugins
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*
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* @param object $user full user record object
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* @return void
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*/
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function session_set_user($user) {
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$_SESSION['USER'] = $user;
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check_enrolment_plugins($_SESSION['USER']);
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load_all_capabilities();
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sesskey(); // init session key
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}
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/**
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* Is current $USER logged-in-as somebody else?
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* @return bool
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*/
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function session_is_loggedinas() {
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return !empty($_SESSION['USER']->realuser);
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}
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/**
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* Returns the $USER object ignoring current login-as session
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* @return object user object
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*/
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function session_get_realuser() {
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if (session_is_loggedinas()) {
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return $_SESSION['REALUSER'];
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} else {
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return $_SESSION['USER'];
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}
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}
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/**
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* Login as another user - no security checks here.
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* @param int $userid
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* @param object $context
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* @return void
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*/
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function session_loginas($userid, $context) {
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if (session_is_loggedinas()) {
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return;
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}
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// switch to fresh new $SESSION
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$_SESSION['REALSESSION'] = $_SESSION['SESSION'];
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$_SESSION['SESSION'] = new object();
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/// Create the new $USER object with all details and reload needed capabilitites
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$_SESSION['REALUSER'] = $_SESSION['USER'];
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$user = get_complete_user_data('id', $userid);
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$user->realuser = $_SESSION['REALUSER']->id;
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$user->loginascontext = $context;
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session_set_user($user);
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}
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/**
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* Terminate login-as session
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* @return void
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*/
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function session_unloginas() {
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if (!session_is_loggedinas()) {
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return;
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}
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$_SESSION['SESSION'] = $_SESSION['REALSESSION'];
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unset($_SESSION['REALSESSION']);
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$_SESSION['USER'] = $_SESSION['REALUSER'];
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unset($_SESSION['REALUSER']);
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}
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/**
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* Enable cookieless sessions by including $CFG->usesid=true;
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* in config.php.
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* Based on code from php manual by Richard at postamble.co.uk
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* Attempts to use cookies if cookies not present then uses session ids attached to all urls and forms to pass session id from page to page.
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* If site is open to google, google is given guest access as usual and there are no sessions. No session ids will be attached to urls for googlebot.
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* This doesn't require trans_sid to be turned on but this is recommended for better performance
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* you should put :
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* session.use_trans_sid = 1
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* in your php.ini file and make sure that you don't have a line like this in your php.ini
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* session.use_only_cookies = 1
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* @author Richard at postamble.co.uk and Jamie Pratt
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* @license http://www.gnu.org/copyleft/gpl.html GNU Public License
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*/
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/**
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* You won't call this function directly. This function is used to process
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* text buffered by php in an output buffer. All output is run through this function
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* before it is ouput.
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* @param string $buffer is the output sent from php
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* @return string the output sent to the browser
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*/
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function sid_ob_rewrite($buffer){
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$replacements = array(
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*")([^"]*)(")/i',
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*\')([^\']*)(\')/i');
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$buffer = preg_replace_callback($replacements, 'sid_rewrite_link_tag', $buffer);
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$buffer = preg_replace('/<form\s[^>]*>/i',
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'\0<input type="hidden" name="' . session_name() . '" value="' . session_id() . '"/>', $buffer);
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return $buffer;
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}
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/**
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* You won't call this function directly. This function is used to process
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* text buffered by php in an output buffer. All output is run through this function
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* before it is ouput.
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* This function only processes absolute urls, it is used when we decide that
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* php is processing other urls itself but needs some help with internal absolute urls still.
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* @param string $buffer is the output sent from php
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* @return string the output sent to the browser
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*/
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function sid_ob_rewrite_absolute($buffer){
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$replacements = array(
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*")((?:http|https)[^"]*)(")/i',
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'/(<\s*(a|link|script|frame|area)\s[^>]*(href|src)\s*=\s*\')((?:http|https)[^\']*)(\')/i');
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$buffer = preg_replace_callback($replacements, 'sid_rewrite_link_tag', $buffer);
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$buffer = preg_replace('/<form\s[^>]*>/i',
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'\0<input type="hidden" name="' . session_name() . '" value="' . session_id() . '"/>', $buffer);
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return $buffer;
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}
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/**
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* A function to process link, a and script tags found
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* by preg_replace_callback in {@link sid_ob_rewrite($buffer)}.
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*/
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function sid_rewrite_link_tag($matches){
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$url = $matches[4];
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$url = sid_process_url($url);
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return $matches[1].$url.$matches[5];
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}
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/**
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* You can call this function directly. This function is used to process
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* urls to add a moodle session id to the url for internal links.
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* @param string $url is a url
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* @return string the processed url
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*/
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function sid_process_url($url) {
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global $CFG;
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if ((preg_match('/^(http|https):/i', $url)) // absolute url
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&& ((stripos($url, $CFG->wwwroot)!==0) && stripos($url, $CFG->httpswwwroot)!==0)) { // and not local one
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return $url; //don't attach sessid to non local urls
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}
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if ($url[0]=='#' || (stripos($url, 'javascript:')===0)) {
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return $url; //don't attach sessid to anchors
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}
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if (strpos($url, session_name())!==FALSE) {
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return $url; //don't attach sessid to url that already has one sessid
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}
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if (strpos($url, "?")===FALSE) {
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$append = "?".strip_tags(session_name() . '=' . session_id());
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} else {
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$append = "&".strip_tags(session_name() . '=' . session_id());
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}
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//put sessid before any anchor
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$p = strpos($url, "#");
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if ($p!==FALSE){
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$anch = substr($url, $p);
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$url = substr($url, 0, $p).$append.$anch ;
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} else {
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$url .= $append ;
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}
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return $url;
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}
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/**
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* Call this function before there has been any output to the browser to
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* buffer output and add session ids to all internal links.
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*/
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function sid_start_ob(){
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global $CFG;
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//don't attach sess id for bots
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if (!empty($_SERVER['HTTP_USER_AGENT'])) {
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if (!empty($CFG->opentogoogle)) {
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if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false) {
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@ini_set('session.use_trans_sid', '0'); // try and turn off trans_sid
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$CFG->usesid=false;
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return;
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}
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if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false) {
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@ini_set('session.use_trans_sid', '0'); // try and turn off trans_sid
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$CFG->usesid=false;
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return;
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}
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}
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if (strpos($_SERVER['HTTP_USER_AGENT'], 'W3C_Validator') !== false) {
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@ini_set('session.use_trans_sid', '0'); // try and turn off trans_sid
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$CFG->usesid=false;
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return;
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|
}
|
|
}
|
|
|
|
@ini_set('session.use_trans_sid', '1'); // try and turn on trans_sid
|
|
|
|
if (ini_get('session.use_trans_sid') != 0) {
|
|
// use trans sid as its available
|
|
ini_set('url_rewriter.tags', 'a=href,area=href,script=src,link=href,frame=src,form=fakeentry');
|
|
ob_start('sid_ob_rewrite_absolute');
|
|
} else {
|
|
//rewrite all links ourselves
|
|
ob_start('sid_ob_rewrite');
|
|
}
|
|
}
|
|
|