fix matcher not working with i18n

.changeset/fifty-clocks-report.md

@@ -0,0 +1,5 @@
+---
+"open-next": patch
+---
+
+fix middleware and headers matcher not working properly with i18n

examples/pages-router/next.config.js

@@ -12,6 +12,17 @@ const nextConfig = {
   eslint: {
     ignoreDuringBuilds: true,
   },
+  headers: () => [
+    {
+      source: "/",
+      headers: [
+        {
+          key: "x-custom-header",
+          value: "my custom header value",
+        },
+      ],
+    },
+  ],
   rewrites: () => [
     { source: "/rewrite", destination: "/", locale: false },
     {

examples/pages-router/src/middleware.ts

@@ -0,0 +1,13 @@
+import { NextRequest, NextResponse } from "next/server";
+
+export function middleware(request: NextRequest) {
+  return NextResponse.next({
+    headers: {
+      "x-from-middleware": "true",
+    },
+  });
+}
+
+export const config = {
+  matcher: ["/"],
+};

packages/open-next/src/core/routing/matcher.ts

@@ -144,14 +144,24 @@ export function addNextConfigHeaders(
 
   const requestHeaders: Record<string, string> = {};
 
-  for (const { headers, has, missing, regex, source } of configHeaders) {
+  const localizedRawPath = localizePath(event);
+
+  for (const {
+    headers,
+    has,
+    missing,
+    regex,
+    source,
+    locale,
+  } of configHeaders) {
+    const path = locale === false ? rawPath : localizedRawPath;
     if (
-      new RegExp(regex).test(rawPath) &&
+      new RegExp(regex).test(path) &&
       checkHas(matcher, has) &&
       checkHas(matcher, missing, true)
     ) {
       const fromSource = match(source);
-      const _match = fromSource(rawPath);
+      const _match = fromSource(path);
       headers.forEach((h) => {
         try {
           const key = convertMatch(_match, compile(h.key), h.key);

packages/open-next/src/core/routing/middleware.ts

@@ -4,6 +4,7 @@ import { MiddlewareManifest, NextConfig } from "config/index.js";
 import { InternalEvent, InternalResult } from "types/open-next.js";
 import { emptyReadableStream } from "utils/stream.js";
 
+import { localizePath } from "./i18n/index.js";
 //NOTE: we should try to avoid importing stuff from next as much as possible
 // every release of next could break this
 // const { run } = require("next/dist/server/web/sandbox");
@@ -32,33 +33,12 @@ type MiddlewareOutputEvent = InternalEvent & {
 // and res.body prior to processing the next-server.
 // @returns undefined | res.end()
 
-// NOTE: We need to normalize the locale path before passing it to the middleware
-// See https://github.com/vercel/next.js/blob/39589ff35003ba73f92b7f7b349b3fdd3458819f/packages/next/src/shared/lib/i18n/normalize-locale-path.ts#L15
-function normalizeLocalePath(pathname: string) {
-  // first item will be empty string from splitting at first char
-  const pathnameParts = pathname.split("/");
-  const locales = NextConfig.i18n?.locales;
-
-  (locales || []).some((locale) => {
-    if (
-      pathnameParts[1] &&
-      pathnameParts[1].toLowerCase() === locale.toLowerCase()
-    ) {
-      pathnameParts.splice(1, 1);
-      pathname = pathnameParts.join("/") || "/";
-      return true;
-    }
-    return false;
-  });
-
-  return locales && !pathname.endsWith("/") ? `${pathname}/` : pathname;
-}
 //    if res.end() is return, the parent needs to return and not process next server
 export async function handleMiddleware(
   internalEvent: InternalEvent,
 ): Promise<MiddlewareOutputEvent | InternalResult> {
-  const { rawPath, query } = internalEvent;
-  const normalizedPath = normalizeLocalePath(rawPath);
+  const { query } = internalEvent;
+  const normalizedPath = localizePath(internalEvent);
   // We only need the normalizedPath to check if the middleware should run
   const hasMatch = middleMatch.some((r) => r.test(normalizedPath));
   if (!hasMatch) return internalEvent;
@@ -68,7 +48,7 @@ export async function handleMiddleware(
   const host = internalEvent.headers.host
     ? `https://${internalEvent.headers.host}`
     : "http://localhost:3000";
-  const initialUrl = new URL(rawPath, host);
+  const initialUrl = new URL(normalizedPath, host);
   initialUrl.search = convertToQueryString(query);
   const url = initialUrl.toString();
   // console.log("url", url, normalizedPath);

packages/tests-e2e/tests/pagesRouter/i18n.test.ts

@@ -0,0 +1,17 @@
+import { expect, test } from "@playwright/test";
+
+test("Next config headers with i18n", async ({ page }) => {
+  const responsePromise = page.waitForResponse((response) => {
+    return response.status() === 200;
+  });
+  await page.goto("/");
+
+  const response = await responsePromise;
+  // Response header should be set
+  const headers = response.headers();
+  // Headers from next.config.js should be set
+  expect(headers["x-custom-header"]).toEqual("my custom header value");
+
+  // Headers from middleware should be set
+  expect(headers["x-from-middleware"]).toEqual("true");
+});