OutputPage: Factor out CdnCacheEpoch logic and cover with tests

Bug: T178629
Change-Id: Ife7dd79677c2b5353317e06ac7ed521edd6193cc

diff --git a/includes/OutputPage.php b/includes/OutputPage.php
index dd64413..37527cf 100644 (file)
--- a/includes/OutputPage.php
+++ b/includes/OutputPage.php
@@ -752,8 +752,10 @@ class OutputPage extends ContextSource {
                        'epoch' => $config->get( 'CacheEpoch' )
                ];
                if ( $config->get( 'UseSquid' ) ) {
-                       // T46570: the core page itself may not change, but resources might
-                       $modifiedTimes['sepoch'] = wfTimestamp( TS_MW, time() - $config->get( 'SquidMaxage' ) );
+                       $modifiedTimes['sepoch'] = wfTimestamp( TS_MW, $this->getCdnCacheEpoch(
+                               time(),
+                               $config->get( 'SquidMaxage' )
+                       ) );
                }
                Hooks::run( 'OutputPageCheckLastModified', [ &$modifiedTimes, $this ] );
 
@@ -815,6 +817,19 @@ class OutputPage extends ContextSource {
                return true;
        }
 
+       /**
+        * @param int $reqTime Time of request (eg. now)
+        * @param int $maxAge Cache TTL in seconds
+        * @return int Timestamp
+        */
+       private function getCdnCacheEpoch( $reqTime, $maxAge ) {
+               // Ensure Last-Modified is never more than (wgSquidMaxage) in the past,
+               // because even if the wiki page content hasn't changed since, static
+               // resources may have changed (skin HTML, interface messages, urls, etc.)
+               // and must roll-over in a timely manner (T46570)
+               return $reqTime - $maxAge;
+       }
+
        /**
         * Override the last modified timestamp
         *

diff --git a/tests/phpunit/includes/OutputPageTest.php b/tests/phpunit/includes/OutputPageTest.php
index 81bbcd7..0a657d8 100644 (file)
--- a/tests/phpunit/includes/OutputPageTest.php
+++ b/tests/phpunit/includes/OutputPageTest.php
@@ -124,6 +124,47 @@ class OutputPageTest extends MediaWikiTestCase {
                ] );
        }
 
+       public static function provideCdnCacheEpoch() {
+               $base = [
+                       'pageTime' => '2011-04-01T12:00:00+00:00',
+                       'maxAge' => 24 * 3600,
+               ];
+               return [
+                       'after 1s' => [ $base + [
+                               'reqTime' => '2011-04-01T12:00:01+00:00',
+                               'expect' => '2011-04-01T12:00:00+00:00',
+                       ] ],
+                       'after 23h' => [ $base + [
+                               'reqTime' => '2011-04-02T11:00:00+00:00',
+                               'expect' => '2011-04-01T12:00:00+00:00',
+                       ] ],
+                       'after 24h and a bit' => [ $base + [
+                               'reqTime' => '2011-04-02T12:34:56+00:00',
+                               'expect' => '2011-04-01T12:34:56+00:00',
+                       ] ],
+                       'after a year' => [ $base + [
+                               'reqTime' => '2012-05-06T00:12:07+00:00',
+                               'expect' => '2012-05-05T00:12:07+00:00',
+                       ] ],
+               ];
+       }
+
+       /**
+        * @dataProvider provideCdnCacheEpoch
+        */
+       public function testCdnCacheEpoch( $params ) {
+               $out = TestingAccessWrapper::newFromObject( $this->newInstance() );
+               $reqTime = strtotime( $params['reqTime'] );
+               $pageTime = strtotime( $params['pageTime'] );
+               $actual = max( $pageTime, $out->getCdnCacheEpoch( $reqTime, $params['maxAge'] ) );
+
+               $this->assertEquals(
+                       $params['expect'],
+                       gmdate( DateTime::ATOM, $actual ),
+                       'cdn epoch'
+               );
+       }
+
        /**
         * Tests screen requests, without either query parameter set
         * @covers OutputPage::transformCssMedia