From 85edec239e264068972ce3b880a2d5c55c013a58 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Mon, 9 Nov 2015 22:57:00 -0800
Subject: [PATCH] API DB commit and sticky DC cookie fixes

* Make sure the API commits DBs *before* sending the
  response, in case something goes south which would
  make a sent response wrong.
* Make sticky DC cookies trigger with api.php too.
* Make sure UseDC cookies do not end up with a prefix.
  VCL rules should not have to deal with having a DB
  name as a prefix or such. This was an oversight.

Change-Id: I9e4090ab15c1c1493b0589a710184745dac9b0c1
---
 includes/MediaWiki.php   | 24 +++++++++++++++++-------
 includes/api/ApiMain.php |  3 +++
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/includes/MediaWiki.php b/includes/MediaWiki.php
index d048b57cfa..22b896f6ef 100644
--- a/includes/MediaWiki.php
+++ b/includes/MediaWiki.php
@@ -486,13 +486,22 @@ class MediaWiki {
 		$this->doPostOutputShutdown( 'normal' );
 	}
 
+	/**
+	 * @see MediaWiki::preOutputCommit()
+	 * @since 1.26
+	 */
+	public function doPreOutputCommit() {
+		self::preOutputCommit( $this->context );
+	}
+
 	/**
 	 * This function commits all DB changes as needed before
 	 * the user can receive a response (in case commit fails)
 	 *
-	 * @since 1.26
+	 * @param IContextSource $context
+	 * @since 1.27
 	 */
-	public function doPreOutputCommit() {
+	public static function preOutputCommit( IContextSource $context ) {
 		// Either all DBs should commit or none
 		ignore_user_abort( true );
 
@@ -505,16 +514,17 @@ class MediaWiki {
 
 		// Set a cookie to tell all CDN edge nodes to "stick" the user to the
 		// DC that handles this POST request (e.g. the "master" data center)
-		$request = $this->context->getRequest();
+		$request = $context->getRequest();
+		$config = $context->getConfig();
 		if ( $request->wasPosted() && $factory->hasOrMadeRecentMasterChanges() ) {
-			$expires = time() + $this->config->get( 'DataCenterUpdateStickTTL' );
-			$request->response()->setCookie( 'UseDC', 'master', $expires );
+			$expires = time() + $config->get( 'DataCenterUpdateStickTTL' );
+			$request->response()->setCookie( 'UseDC', 'master', $expires, array( 'prefix' => '' ) );
 		}
 
 		// Avoid letting a few seconds of slave lag cause a month of stale data
 		if ( $factory->laggedSlaveUsed() ) {
-			$maxAge = $this->config->get( 'CdnMaxageLagged' );
-			$this->context->getOutput()->lowerCdnMaxage( $maxAge );
+			$maxAge = $config->get( 'CdnMaxageLagged' );
+			$context->getOutput()->lowerCdnMaxage( $maxAge );
 			$request->response()->header( "X-Database-Lagged: true" );
 			wfDebugLog( 'replication', "Lagged DB used; CDN cache TTL limited to $maxAge seconds" );
 		}
diff --git a/includes/api/ApiMain.php b/includes/api/ApiMain.php
index 27684096e8..14b27ee8c7 100644
--- a/includes/api/ApiMain.php
+++ b/includes/api/ApiMain.php
@@ -440,6 +440,9 @@ class ApiMain extends ApiBase {
 		// Log the request whether or not there was an error
 		$this->logRequest( microtime( true ) - $t );
 
+		// Commit DBs and send any related cookies and headers
+		MediaWiki::preOutputCommit( $this->getContext() );
+
 		// Send cache headers after any code which might generate an error, to
 		// avoid sending public cache headers for errors.
 		$this->sendCacheHeaders( $isError );
-- 
2.20.1