From 3654b693e3c87585d421b0fce088f1c33b8306a3 Mon Sep 17 00:00:00 2001
From: Alexander Zinchuk <alx.zinchuk@gmail.com>
Date: Fri, 15 Sep 2023 17:14:00 +0200
Subject: [PATCH] Fix referrer RegEx for permanent version redirect (#3864)

---
 src/util/permanentWebVersion.ts | 42 +++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/src/util/permanentWebVersion.ts b/src/util/permanentWebVersion.ts
index 6dafe1a9a..dba30b135 100644
--- a/src/util/permanentWebVersion.ts
+++ b/src/util/permanentWebVersion.ts
@@ -3,7 +3,7 @@ import { getActions } from '../global';
 import { PRODUCTION_HOSTNAME, WEB_VERSION_BASE } from '../config';
 import { clearWebsync } from './websync';
 
-const SEARCH_ENGINE_REFERRERS = ['google', 'bing', 'duckduckgo', 'ya', 'yandex'];
+const SEARCH_ENGINE_REGEX = /(^|\.)(google|bing|duckduckgo|ya|yandex)\./i;
 // Handled by the legacy version. Cannot be updated
 const PERMANENT_VERSION_KEY = 'kz_version';
 const AVAILABLE_VERSIONS = ['Z', 'K'] as const;
@@ -34,24 +34,30 @@ export function checkAndAssignPermanentWebVersion() {
   if (window.location.hostname !== PRODUCTION_HOSTNAME) return;
 
   const referrer = document.referrer.toLowerCase();
-  if (!SEARCH_ENGINE_REFERRERS.some((engine) => referrer.match(`(\\/\\/:|\\.)${engine}\\.`))) return;
+  if (!referrer) return;
+  try {
+    const isSearchEngine = new URL(referrer).host.match(SEARCH_ENGINE_REGEX);
+    if (!isSearchEngine) return;
 
-  const currentVersion = getPermanentWebVersion();
-  if (currentVersion) {
-    if (currentVersion !== CLIENT_VERSION) {
-      switchPermanentWebVersion(currentVersion);
+    const currentVersion = getPermanentWebVersion();
+    if (currentVersion) {
+      if (currentVersion !== CLIENT_VERSION) {
+        switchPermanentWebVersion(currentVersion);
+      }
+      return;
     }
-    return;
+
+    const urlParams = new URLSearchParams(window.location.search);
+    const hasTest = (urlParams.get('test') ?? undefined) !== undefined;
+    const shouldRedirect = Math.random() < 0.5;
+
+    if (hasTest || !shouldRedirect) {
+      setPermanentWebVersion('Z');
+      return;
+    }
+
+    switchPermanentWebVersion('K');
+  } catch (e) {
+    // Ignore
   }
-
-  const urlParams = new URLSearchParams(window.location.search);
-  const hasTest = (urlParams.get('test') ?? undefined) !== undefined;
-  const shouldRedirect = Math.random() < 0.5;
-
-  if (hasTest || !shouldRedirect) {
-    setPermanentWebVersion('Z');
-    return;
-  }
-
-  switchPermanentWebVersion('K');
 }