fix 404 when no route match at all

.changeset/tame-pets-juggle.md

@@ -0,0 +1,5 @@
+---
+"open-next": patch
+---
+
+fix 404 when no route match at all

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

@@ -284,6 +284,12 @@ export function fixCacheHeaderForHtmlPages(
   rawPath: string,
   headers: OutgoingHttpHeaders,
 ) {
+  // We don't want to cache error pages
+  if (rawPath === "/404" || rawPath === "/500") {
+    headers[CommonHeaders.CACHE_CONTROL] =
+      "private, no-cache, no-store, max-age=0, must-revalidate";
+    return;
+  }
   // WORKAROUND: `NextServer` does not set cache headers for HTML pages — https://github.com/serverless-stack/open-next#workaround-nextserver-does-not-set-cache-headers-for-html-pages
   if (HtmlPages.includes(rawPath)) {
     headers[CommonHeaders.CACHE_CONTROL] =

packages/open-next/src/core/routingHandler.ts

@@ -22,6 +22,14 @@ export interface MiddlewareOutputEvent {
   origin: Origin | false;
 }
 
+const staticRegexp = RoutesManifest.routes.static.map(
+  (route) => new RegExp(route.regex),
+);
+
+const dynamicRegexp = RoutesManifest.routes.dynamic.map(
+  (route) => new RegExp(route.regex),
+);
+
 export default async function routingHandler(
   event: InternalEvent,
 ): Promise<InternalResult | MiddlewareOutputEvent> {
@@ -47,6 +55,8 @@ export default async function routingHandler(
     internalEvent = middleware;
   }
 
+  // At this point internalEvent is an InternalEvent or a MiddlewareOutputEvent
+
   let isExternalRewrite = middleware.externalRewrite ?? false;
   if (!isExternalRewrite) {
     // First rewrite to be applied
@@ -57,9 +67,11 @@ export default async function routingHandler(
     internalEvent = beforeRewrites.internalEvent;
     isExternalRewrite = beforeRewrites.isExternalRewrite;
   }
-  const isStaticRoute = RoutesManifest.routes.static.some((route) =>
-    new RegExp(route.regex).test(event.rawPath),
-  );
+  const isStaticRoute =
+    !isExternalRewrite &&
+    staticRegexp.some((route) =>
+      route.test((internalEvent as InternalEvent).rawPath),
+    );
 
   if (!isStaticRoute && !isExternalRewrite) {
     // Second rewrite to be applied
@@ -74,9 +86,11 @@ export default async function routingHandler(
   // We want to run this just before the dynamic route check
   internalEvent = handleFallbackFalse(internalEvent, PrerenderManifest);
 
-  const isDynamicRoute = RoutesManifest.routes.dynamic.some((route) =>
-    new RegExp(route.regex).test(event.rawPath),
-  );
+  const isDynamicRoute =
+    !isExternalRewrite &&
+    dynamicRegexp.some((route) =>
+      route.test((internalEvent as InternalEvent).rawPath),
+    );
   if (!isDynamicRoute && !isStaticRoute && !isExternalRewrite) {
     // Fallback rewrite to be applied
     const fallbackRewrites = handleRewrites(
@@ -87,6 +101,41 @@ export default async function routingHandler(
     isExternalRewrite = fallbackRewrites.isExternalRewrite;
   }
 
+  // Api routes are not present in the routes manifest except if they're not behind /api
+  // /api even if it's a page route doesn't get generated in the manifest
+  // Ideally we would need to properly check api routes here
+  const isApiRoute =
+    internalEvent.rawPath === "/api" ||
+    internalEvent.rawPath.startsWith("/api/");
+
+  const isRouteFoundBeforeAllRewrites =
+    isStaticRoute || isDynamicRoute || isExternalRewrite;
+
+  // If we still haven't found a route, we show the 404 page
+  // We need to ensure that rewrites are applied before showing the 404 page
+  if (
+    !isRouteFoundBeforeAllRewrites &&
+    !isApiRoute &&
+    // We need to check again once all rewrites have been applied
+    !staticRegexp.some((route) =>
+      route.test((internalEvent as InternalEvent).rawPath),
+    ) &&
+    !dynamicRegexp.some((route) =>
+      route.test((internalEvent as InternalEvent).rawPath),
+    )
+  ) {
+    internalEvent = {
+      ...internalEvent,
+      rawPath: "/404",
+      url: "/404",
+      headers: {
+        ...internalEvent.headers,
+        "x-middleware-response-cache-control":
+          "private, no-cache, no-store, max-age=0, must-revalidate",
+      },
+    };
+  }
+
   // We apply the headers from the middleware response last
   Object.entries({
     ...middlewareResponseHeaders,

packages/tests-e2e/tests/pagesRouter/404.test.ts

@@ -0,0 +1,13 @@
+import { expect, test } from "@playwright/test";
+
+test("should return 404 on a route not corresponding to any route", async ({
+  page,
+}) => {
+  const result = await page.goto("/not-existing/route");
+  expect(result).toBeDefined();
+  expect(result?.status()).toBe(404);
+  const headers = result?.headers();
+  expect(headers?.["cache-control"]).toBe(
+    "private, no-cache, no-store, max-age=0, must-revalidate",
+  );
+});