Fix infinite redirect when a double slash appears in a URL (#2449)

* Fix infinite redirect when a double slash appears in a URL

.changeset/serious-islands-double.md

@@ -0,0 +1,6 @@
+---
+'@shopify/remix-oxygen': patch
+'@shopify/mini-oxygen': patch
+---
+
+Prevent infinite redirects when a double slash exists in the URL

packages/mini-oxygen/src/vite/utils.ts

@@ -10,13 +10,12 @@ import type {ViteDevServer} from 'vite';
  */
 export function toURL(req: string | IncomingMessage = '/', origin?: string) {
   const isRequest = typeof req !== 'string';
-  const pathname = (isRequest ? req.url : req) || '/';
+  let pathname = (isRequest ? req.url : req) || '/';
 
   return new URL(
-    pathname,
-    origin ||
+    (origin ||
       (isRequest && req.headers.host && `http://${req.headers.host}`) ||
-      'http://example.com',
+      'http://example.com') + pathname,
   );
 }
 

packages/remix-oxygen/src/server.ts

@@ -33,6 +33,17 @@ export function createRequestHandler<Context = unknown>({
       });
     }
 
+    const url = new URL(request.url);
+
+    if (url.pathname.includes('//')) {
+      return new Response(null, {
+        status: 301,
+        headers: {
+          location: url.pathname.replace(/\/+/g, '/'),
+        },
+      });
+    }
+
     const context = getLoadContext
       ? ((await getLoadContext(request)) as AppLoadContext)
       : undefined;