From 203d2c9c116431c1bdcfbc322ef5b5730e9589b5 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Mon, 3 Aug 2015 13:35:50 -0700
Subject: [PATCH] Moved ObjectCacheSessionHandler renewal logic to
 wfSetupSession()

* This should trigger more reliably than the shutdown function
  callback, which is really only there for sanity to make sure
  session close/write happens.

Change-Id: I9a1aa76de121ba8de33b3fa850bd223929fae404
---
 includes/GlobalFunctions.php                  | 11 +++++--
 .../objectcache/ObjectCacheSessionHandler.php | 30 +++++++++++++------
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/includes/GlobalFunctions.php b/includes/GlobalFunctions.php
index f98a0cf349..2b9bc251d7 100644
--- a/includes/GlobalFunctions.php
+++ b/includes/GlobalFunctions.php
@@ -3461,8 +3461,9 @@ function wfResetSessionID() {
  * @param bool $sessionId
  */
 function wfSetupSession( $sessionId = false ) {
-	global $wgSessionsInMemcached, $wgSessionsInObjectCache, $wgCookiePath, $wgCookieDomain,
-			$wgCookieSecure, $wgCookieHttpOnly, $wgSessionHandler;
+	global $wgSessionsInMemcached, $wgSessionsInObjectCache, $wgSessionHandler;
+	global $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $wgCookieHttpOnly;
+
 	if ( $wgSessionsInObjectCache || $wgSessionsInMemcached ) {
 		ObjectCacheSessionHandler::install();
 	} elseif ( $wgSessionHandler && $wgSessionHandler != ini_get( 'session.save_handler' ) ) {
@@ -3470,6 +3471,7 @@ function wfSetupSession( $sessionId = false ) {
 		# hasn't already been set to the desired value (that causes errors)
 		ini_set( 'session.save_handler', $wgSessionHandler );
 	}
+
 	session_set_cookie_params(
 		0, $wgCookiePath, $wgCookieDomain, $wgCookieSecure, $wgCookieHttpOnly );
 	session_cache_limiter( 'private, must-revalidate' );
@@ -3478,9 +3480,14 @@ function wfSetupSession( $sessionId = false ) {
 	} else {
 		wfFixSessionID();
 	}
+
 	MediaWiki\suppressWarnings();
 	session_start();
 	MediaWiki\restoreWarnings();
+
+	if ( $wgSessionsInObjectCache || $wgSessionsInMemcached ) {
+		ObjectCacheSessionHandler::renewCurrentSession();
+	}
 }
 
 /**
diff --git a/includes/objectcache/ObjectCacheSessionHandler.php b/includes/objectcache/ObjectCacheSessionHandler.php
index 1430dd8c3d..8a7b2980b6 100644
--- a/includes/objectcache/ObjectCacheSessionHandler.php
+++ b/includes/objectcache/ObjectCacheSessionHandler.php
@@ -21,6 +21,8 @@
  * @ingroup Cache
  */
 
+use MediaWiki\Logger\LoggerFactory;
+
 /**
  * Session storage in object cache.
  * Used if $wgSessionsInObjectCache is true.
@@ -28,9 +30,6 @@
  * @ingroup Cache
  */
 class ObjectCacheSessionHandler {
-
-	const TTL_REFRESH_WINDOW = 600; // refresh if expiring in 10 minutes
-
 	/**
 	 * Install a session handler for the current web request
 	 */
@@ -145,20 +144,33 @@ class ObjectCacheSessionHandler {
 	 * See the comment inside ObjectCacheSessionHandler::install for rationale.
 	 */
 	static function handleShutdown() {
+		session_write_close();
+	}
+
+	/**
+	 * Pre-emptive session renewal function
+	 */
+	static function renewCurrentSession() {
 		global $wgObjectCacheSessionExpiry;
 
+		// Once a session is at half TTL, renew it
+		$window = $wgObjectCacheSessionExpiry / 2;
+		$logger = LoggerFactory::getInstance( 'SessionHandler' );
+
 		$now = microtime( true );
 		// Session are only written in object stores when $_SESSION changes,
 		// which also renews the TTL ($wgObjectCacheSessionExpiry). If a user
 		// is active but not causing session data changes, it may suddenly
-		// as they view a form, blocking the first submission.
+		// expire as they view a form, blocking the first submission.
 		// Make a dummy change every so often to avoid this.
-		if ( !isset( $_SESSION['wsExpiresUnix'] )
-			|| ( $now + self::TTL_REFRESH_WINDOW ) > isset( $_SESSION['wsExpiresUnix'] )
-		) {
+		if ( !isset( $_SESSION['wsExpiresUnix'] ) ) {
 			$_SESSION['wsExpiresUnix'] = $now + $wgObjectCacheSessionExpiry;
-		}
 
-		session_write_close();
+			$logger->info( "Set expiry for session " . session_id(), array() );
+		} elseif ( ( $now + $window ) > $_SESSION['wsExpiresUnix'] ) {
+			$_SESSION['wsExpiresUnix'] = $now + $wgObjectCacheSessionExpiry;
+
+			$logger->info( "Renewed session " . session_id(), array() );
+		}
 	}
 }
-- 
2.20.1