From 6ccd564d566e9d00465ab887f4ab2814737ec52d Mon Sep 17 00:00:00 2001
From: Jonny Barnes <jonny@jonnybarnes.uk>
Date: Fri, 12 Jan 2018 12:20:36 +0000
Subject: [PATCH] Remove unwanted query parameters from normalized URLs

---
 helpers.php                | 29 +++++++++++++++++++++--------
 tests/Unit/HelpersTest.php | 21 +++++++++++++--------
 2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/helpers.php b/helpers.php
index 7e5a0852..230c6317 100644
--- a/helpers.php
+++ b/helpers.php
@@ -126,20 +126,33 @@ if (! function_exists('normalize_url')) {
 
         // Sort GET params alphabetically, not because the RFC requires it but because it's cool!
         if (isset($url['query'])) {
-            if (preg_match('/&/', $url['query'])) {
-                $s = explode('&', $url['query']);
-                $url['query'] = '';
-                sort($s);
-                foreach ($s as $z) {
-                    $url['query'] .= "{$z}&";
+            $queries = explode('&', $url['query']);
+            $url['query'] = '';
+            sort($queries);
+            foreach ($queries as $query) {
+                //lets drop query params we don’t want
+                $key = stristr($query, '=', true);
+                if (queryKeyIsBanned($key) === false) {
+                    $url['query'] .= "{$query}&";
                 }
-                $url['query'] = preg_replace('/&\Z/', '', $url['query']);
             }
-            $newUrl .= "?{$url['query']}";
+            $url['query'] = preg_replace('/&\Z/', '', $url['query']);
+            if ($url['query'] !== '') {
+                $newUrl .= "?{$url['query']}";
+            }
         }
 
         return $newUrl;
     }
+
+    function queryKeyIsBanned(string $key): bool
+    {
+        $bannedKeys = [
+            'ref_src',
+        ];
+
+        return in_array($key, $bannedKeys);
+    }
 }
 
 // sourced from https://stackoverflow.com/a/9776726
diff --git a/tests/Unit/HelpersTest.php b/tests/Unit/HelpersTest.php
index d1d78298..a9b32150 100644
--- a/tests/Unit/HelpersTest.php
+++ b/tests/Unit/HelpersTest.php
@@ -12,14 +12,6 @@ class HelpersTest extends TestCase
         $this->assertEquals(normalize_url(normalize_url($input)), normalize_url($input));
     }
 
-    /**
-     * @dataProvider urlProvider
-     */
-    public function test_normalize_url($input, $output)
-    {
-        $this->assertEquals($output, normalize_url($input));
-    }
-
     public function urlProvider()
     {
         return [
@@ -27,9 +19,22 @@ class HelpersTest extends TestCase
             ['https://example.org:443/', 'https://example.org'],
             ['http://www.foo.bar/index.php/', 'http://www.foo.bar'],
             ['https://example.org/?foo=bar&baz=true', 'https://example.org?baz=true&foo=bar'],
+            [
+                'http://example.org/?ref_src=twcamp^share|twsrc^ios|twgr^software.studioh.Indigenous.share-micropub',
+                'http://example.org',
+            ],
         ];
     }
 
+    /**
+     * @dataProvider urlProvider
+     * @group temp
+     */
+    public function test_normalize_url($input, $output)
+    {
+        $this->assertEquals($output, normalize_url($input));
+    }
+
     public function test_pretty_print_json()
     {
         $json = <<<JSON