From 7cd10ab05c0600f8dd859905ac506cc3bbcf04af Mon Sep 17 00:00:00 2001
From: Peter Burnett <peterburnett@catalyst-au.net>
Date: Mon, 18 Jan 2021 15:47:30 +1000
Subject: [PATCH] Updated DOM element matching to allow for "//" urls in images

---
 .../maintenance_static_page_io.php            |  4 +++-
 .../maintenance_static_page_test.php          | 21 ++++++++++++++-----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/classes/local/controllers/maintenance_static_page_io.php b/classes/local/controllers/maintenance_static_page_io.php
index eeafb53..6ec6e97 100644
--- a/classes/local/controllers/maintenance_static_page_io.php
+++ b/classes/local/controllers/maintenance_static_page_io.php
@@ -44,11 +44,13 @@ defined('MOODLE_INTERNAL') || die();
 class maintenance_static_page_io {
     /**
      * Checks if the given string starts with "http://" or "https://".
+     * Also checks for "//" at the start of image, which setting_file_url still uses.
+     *
      * @param $url
      * @return bool
      */
     public static function is_url($url) {
-        return (bool)preg_match('#^http(s)?://#', $url);
+        return ((bool) preg_match('#^http(s)?://#', $url) || (bool) preg_match('#^//#', $url));
     }
 
     /**
diff --git a/tests/phpunit/local/controllers/maintenance_static_page_test.php b/tests/phpunit/local/controllers/maintenance_static_page_test.php
index f632284..2318ff8 100644
--- a/tests/phpunit/local/controllers/maintenance_static_page_test.php
+++ b/tests/phpunit/local/controllers/maintenance_static_page_test.php
@@ -260,11 +260,22 @@ class maintenance_static_page_test extends auth_outage_base_testcase {
         self::assertContains('www.example.com/moodle/auth/outage/file.php?file=img.png', $io->get_url_for_file('img.png'));
     }
 
-    public function test_is_url() {
-        self::assertTrue(maintenance_static_page_io::is_url('http://catalyst.net.nz'));
-        self::assertTrue(maintenance_static_page_io::is_url('https://www.catalyst-au.net/'));
-        self::assertFalse(maintenance_static_page_io::is_url('/homepage'));
-        self::assertFalse(maintenance_static_page_io::is_url('file://homepage'));
+    public function is_url_dataprovider() {
+        return [
+            [true, 'http://catalyst.net.nz'],
+            [true, 'https://www.catalyst-au.net/'],
+            [false, '/homepage'],
+            [false, 'file://homepage'],
+            [true, '//catalyst-au.net/img/test.jpg'],
+            [false, '://www.catalyst-au.net/img/test.jpg']
+        ];
+    }
+
+    /**
+     * @dataProvider is_url_dataprovider
+     */
+    public function test_is_url($result, $url) {
+        self::assertEquals($result, maintenance_static_page_io::is_url($url));
     }
 
     public function test_file_get_data() {