From dbd99ccdea30060d352f79f256f07a28143611b5 Mon Sep 17 00:00:00 2001
From: Jerome Bakker <jeabakker@coldtrick.com>
Date: Tue, 16 Feb 2021 10:49:36 +0100
Subject: [PATCH] chore(response): ensure string output in responses

---
 engine/classes/Elgg/Http/ResponseFactory.php  | 11 +++++--
 .../Elgg/Http/ResponseFactoryUnitTest.php     | 30 ++++++++++++++++++-
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/engine/classes/Elgg/Http/ResponseFactory.php b/engine/classes/Elgg/Http/ResponseFactory.php
index c7ebe1f435a..22d57c49d9a 100644
--- a/engine/classes/Elgg/Http/ResponseFactory.php
+++ b/engine/classes/Elgg/Http/ResponseFactory.php
@@ -675,12 +675,19 @@ public function normalize($content = '') {
 	 */
 	public function stringify($content = '') {
 		$content = $this->normalize($content);
-		if (empty($content) || (is_object($content) && is_callable([$content, '__toString']))) {
+		
+		if (is_object($content) && is_callable([$content, '__toString'])) {
 			return (string) $content;
 		}
+		
 		if (is_scalar($content)) {
-			return $content;
+			return (string) $content;
 		}
+		
+		if (empty($content)) {
+			return '';
+		}
+		
 		return json_encode($content, ELGG_JSON_ENCODING);
 	}
 
diff --git a/engine/tests/phpunit/unit/Elgg/Http/ResponseFactoryUnitTest.php b/engine/tests/phpunit/unit/Elgg/Http/ResponseFactoryUnitTest.php
index 0323fe0da42..d27dbb77b84 100644
--- a/engine/tests/phpunit/unit/Elgg/Http/ResponseFactoryUnitTest.php
+++ b/engine/tests/phpunit/unit/Elgg/Http/ResponseFactoryUnitTest.php
@@ -387,7 +387,7 @@ public function testCanParseContext($path, $expected) {
 		$this->assertEquals($expected, $service->parseContext());
 	}
 
-	function requestContextDataProvider() {
+	public function requestContextDataProvider() {
 		return [
 			['ajax/view/foo/bar/', 'view:foo/bar'],
 			['ajax/form/foo/bar/baz/', 'form:foo/bar/baz'],
@@ -400,4 +400,32 @@ function requestContextDataProvider() {
 		];
 	}
 
+	/**
+	 * @dataProvider stringifyProvider
+	 */
+	public function testStringify($input, $expected_output) {
+		$this->createService();
+		
+		$this->assertEquals($expected_output, $this->response_factory->stringify($input));
+	}
+	
+	public function stringifyProvider() {
+		$std = new \stdClass();
+		$std->foo = 'bar';
+		
+		return [
+			['foo', 'foo'],
+			[['foo'], '["foo"]'],
+			['', ''],
+			[[], ''],
+			[false, ''],
+			[true, '1'],
+			[0, '0'],
+			[0.0, '0'],
+			[0.1, '0.1'],
+			[null, ''],
+			[new \stdClass(), '{}'],
+			[$std, '{"foo":"bar"}'],
+		];
+	}
 }