fix: better rewrite handling

Author: ascorbic

demos/custom-routes/pages/[...slug].js

@@ -0,0 +1,3 @@
+export default function Page() {
+  return <p>this is the fallback page to prevent 404s in tests</p>
+}

packages/runtime/src/templates/edge/router-post-middleware.ts

@@ -29,11 +29,14 @@ const handler = async (request: Request, context: Context) => {
   const resultUrl = new URL(result.url)
   const requestUrl = new URL(request.url)
 
+  if (resultUrl.hostname === 'n') {
+    resultUrl.hostname = requestUrl.hostname
+  }
   // External rewrite
-  if (resultUrl.hostname !== 'n' && resultUrl.hostname !== requestUrl.hostname) {
+  if (resultUrl.hostname !== requestUrl.hostname) {
     return fetch(result, request)
   }
-  console.log('rewrite', result.url.slice(resultUrl.origin.length))
-  return context.rewrite(result.url.slice(resultUrl.origin.length))
+
+  return context.rewrite(resultUrl)
 }
 export default handler