From 81d5d8adc2572e8ef765464cb2a72c7274b60fd5 Mon Sep 17 00:00:00 2001
From: Kevin Israel <pleasestand@live.com>
Date: Fri, 8 Jul 2016 16:22:27 -0400
Subject: [PATCH] ApiQuery: Don't mess with PHP output buffering

Specifically, it is not necessary to use output buffering functions
to capture XML generated by the export code because it is already
possible to set the "output sink" object to be used.

* Created a DumpStringOutput class, which appends all output to a
  string property rather than printing output immediately.
* Used that class, instead of ob_start() and ob_get_clean(), in
  ApiQuery and ExportTest.

Change-Id: I238f5d5ec7fd442c845b25cb59ef81ac3285099f
---
 autoload.php                          |  1 +
 includes/api/ApiQuery.php             |  8 ++---
 includes/export/DumpStringOutput.php  | 45 +++++++++++++++++++++++++++
 tests/phpunit/includes/ExportTest.php |  5 +--
 4 files changed, 52 insertions(+), 7 deletions(-)
 create mode 100644 includes/export/DumpStringOutput.php

diff --git a/autoload.php b/autoload.php
index 8e214ce210..57da6a038e 100644
--- a/autoload.php
+++ b/autoload.php
@@ -389,6 +389,7 @@ $wgAutoloadLocalClasses = [
 	'DumpPipeOutput' => __DIR__ . '/includes/export/DumpPipeOutput.php',
 	'DumpRenderer' => __DIR__ . '/maintenance/renderDump.php',
 	'DumpRev' => __DIR__ . '/maintenance/storage/dumpRev.php',
+	'DumpStringOutput' => __DIR__ . '/includes/export/DumpStringOutput.php',
 	'DuplicateJob' => __DIR__ . '/includes/jobqueue/jobs/DuplicateJob.php',
 	'EditAction' => __DIR__ . '/includes/actions/EditAction.php',
 	'EditCLI' => __DIR__ . '/maintenance/edit.php',
diff --git a/includes/api/ApiQuery.php b/includes/api/ApiQuery.php
index ed4d373a7c..1e912561bc 100644
--- a/includes/api/ApiQuery.php
+++ b/includes/api/ApiQuery.php
@@ -443,16 +443,14 @@ class ApiQuery extends ApiBase {
 		}
 
 		$exporter = new WikiExporter( $this->getDB() );
-		// WikiExporter writes to stdout, so catch its
-		// output with an ob
-		ob_start();
+		$sink = new DumpStringOutput;
+		$exporter->setOutputSink( $sink );
 		$exporter->openStream();
 		foreach ( $exportTitles as $title ) {
 			$exporter->pageByTitle( $title );
 		}
 		$exporter->closeStream();
-		$exportxml = ob_get_contents();
-		ob_end_clean();
+		$exportxml = $sink->getOutput();
 
 		// Don't check the size of exported stuff
 		// It's not continuable, so it would cause more
diff --git a/includes/export/DumpStringOutput.php b/includes/export/DumpStringOutput.php
new file mode 100644
index 0000000000..5168225179
--- /dev/null
+++ b/includes/export/DumpStringOutput.php
@@ -0,0 +1,45 @@
+<?php
+/**
+ * Stream outputter that buffers and returns data as a string.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * @ingroup Dump
+ * @since 1.28
+ */
+class DumpStringOutput extends DumpOutput {
+	private $output = '';
+
+	/**
+	 * @param string $string
+	 */
+	function write( $string ) {
+		$this->output .= $string;
+	}
+
+	/**
+	 * Get the string containing the output.
+	 *
+	 * @return string
+	 */
+	public function getOutput() {
+		return $this->output;
+	}
+}
diff --git a/tests/phpunit/includes/ExportTest.php b/tests/phpunit/includes/ExportTest.php
index a2bb97a2bc..c07708158b 100644
--- a/tests/phpunit/includes/ExportTest.php
+++ b/tests/phpunit/includes/ExportTest.php
@@ -30,11 +30,12 @@ class ExportTest extends MediaWikiLangTestCase {
 
 		$title = Title::newFromText( $pageTitle );
 
-		ob_start();
+		$sink = new DumpStringOutput;
+		$exporter->setOutputSink( $sink );
 		$exporter->openStream();
 		$exporter->pageByTitle( $title );
 		$exporter->closeStream();
-		$xmlString = ob_get_clean();
+		$xmlString = $sink->getOutput();
 
 		// This throws error if invalid xml output
 		$xmlObject = simplexml_load_string( $xmlString );
-- 
2.20.1