Introduced User::touch() method to bump the getTouched() value using memcached

* This lets some callers avoid the heavyweight invalidateCache() method

Bug: T91279
Bug: T92357
Change-Id: I8c1c7ff9c5574f0eca23e7effde199ab13a19231

diff --git a/includes/User.php b/includes/User.php
index 97eaa5c..a4ba4a0 100644 (file)
--- a/includes/User.php
+++ b/includes/User.php
@@ -204,8 +204,10 @@ class User implements IDBAccessObject {
        public $mNewpassTime;
 
        public $mEmail;
-
+       /** @var string TS_MW timestamp from the DB */
        public $mTouched;
+       /** @var string TS_MW timestamp from cache */
+       protected $mQuickTouched;
 
        protected $mToken;
 
@@ -429,6 +431,8 @@ class User implements IDBAccessObject {
         * Save user data to the shared cache
         */
        public function saveToCache() {
+               global $wgMemc;
+
                $this->load();
                $this->loadGroups();
                $this->loadOptions();
@@ -442,7 +446,7 @@ class User implements IDBAccessObject {
                }
                $data['mVersion'] = self::VERSION;
                $key = wfMemcKey( 'user', 'id', $this->mId );
-               global $wgMemc;
+
                $wgMemc->set( $key, $data );
        }
 
@@ -2214,9 +2218,10 @@ class User implements IDBAccessObject {
         * Called implicitly from invalidateCache() and saveSettings().
         */
        public function clearSharedCache() {
+               global $wgMemc;
+
                $this->load();
                if ( $this->mId ) {
-                       global $wgMemc;
                        $wgMemc->delete( wfMemcKey( 'user', 'id', $this->mId ) );
                }
        }
@@ -2255,6 +2260,31 @@ class User implements IDBAccessObject {
                }
        }
 
+       /**
+        * Update the "touched" timestamp for the user
+        *
+        * This is useful on various login/logout events when making sure that
+        * a browser or proxy that has multiple tenants does not suffer cache
+        * pollution where the new user sees the old users content. The value
+        * of getTouched() is checked when determining 304 vs 200 responses.
+        * Unlike invalidateCache(), this preserves the User object cache and
+        * avoids database writes.
+        *
+        * @since 1.25
+        */
+       public function touch() {
+               global $wgMemc;
+
+               $this->load();
+
+               if ( $this->mId ) {
+                       $key = wfMemcKey( 'user-quicktouched', 'id', $this->mId );
+                       $timestamp = self::newTouchedTimestamp();
+                       $wgMemc->set( $key, $timestamp );
+                       $this->mQuickTouched = $timestamp;
+               }
+       }
+
        /**
         * Validate the cache for this account.
         * @param string $timestamp A timestamp in TS_MW format
@@ -2267,10 +2297,26 @@ class User implements IDBAccessObject {
 
        /**
         * Get the user touched timestamp
-        * @return string Timestamp
+        * @return string TS_MW Timestamp
         */
        public function getTouched() {
+               global $wgMemc;
+
                $this->load();
+
+               if ( $this->mId ) {
+                       if ( $this->mQuickTouched === null ) {
+                               $key = wfMemcKey( 'user-quicktouched', 'id', $this->mId );
+                               $timestamp = $wgMemc->get( $key );
+                               if ( !$timestamp ) {
+                                       # Set the timestamp to get HTTP 304 cache hits
+                                       $this->touch();
+                               }
+                       }
+
+                       return max( $this->mTouched, $this->mQuickTouched );
+               }
+
                return $this->mTouched;
        }