From 57ea6791f4179f177e8af238a500c5188257c99c Mon Sep 17 00:00:00 2001
From: Alan Agius <17563226+alan-agius4@users.noreply.github.com>
Date: Wed, 17 Dec 2025 09:29:30 +0000
Subject: [PATCH] fix(@angular/ssr): propagate status code to redirect

This commit ensures that status codes set in code are propagated to the redirect when using `Router.navigate`.
---
 packages/angular/ssr/src/app.ts              | 20 +--------
 packages/angular/ssr/src/routes/ng-routes.ts |  8 +---
 packages/angular/ssr/src/utils/redirect.ts   | 46 ++++++++++++++++++++
 packages/angular/ssr/test/app_spec.ts        | 10 ++++-
 4 files changed, 58 insertions(+), 26 deletions(-)
 create mode 100644 packages/angular/ssr/src/utils/redirect.ts

diff --git a/packages/angular/ssr/src/app.ts b/packages/angular/ssr/src/app.ts
index 83b18a25ef72..4c6cbfd3cbf5 100644
--- a/packages/angular/ssr/src/app.ts
+++ b/packages/angular/ssr/src/app.ts
@@ -25,6 +25,7 @@ import { InlineCriticalCssProcessor } from './utils/inline-critical-css';
 import { LRUCache } from './utils/lru-cache';
 import { AngularBootstrap, renderAngular } from './utils/ng';
 import { promiseWithAbort } from './utils/promise';
+import { createRedirectResponse } from './utils/redirect';
 import { buildPathWithParams, joinUrlParts, stripLeadingSlash } from './utils/url';
 
 /**
@@ -351,7 +352,7 @@ export class AngularServerApp {
     }
 
     if (result.redirectTo) {
-      return createRedirectResponse(result.redirectTo, status);
+      return createRedirectResponse(result.redirectTo, responseInit.status);
     }
 
     if (renderMode === RenderMode.Prerender) {
@@ -546,20 +547,3 @@ function appendPreloadHintsToHtml(html: string, preload: readonly string[]): str
     html.slice(bodyCloseIdx),
   ].join('\n');
 }
-
-/**
- * Creates an HTTP redirect response with a specified location and status code.
- *
- * @param location - The URL to which the response should redirect.
- * @param status - The HTTP status code for the redirection. Defaults to 302 (Found).
- *                 See: https://developer.mozilla.org/en-US/docs/Web/API/Response/redirect_static#status
- * @returns A `Response` object representing the HTTP redirect.
- */
-function createRedirectResponse(location: string, status = 302): Response {
-  return new Response(null, {
-    status,
-    headers: {
-      'Location': location,
-    },
-  });
-}
diff --git a/packages/angular/ssr/src/routes/ng-routes.ts b/packages/angular/ssr/src/routes/ng-routes.ts
index e46dd685511a..b60e704371a4 100644
--- a/packages/angular/ssr/src/routes/ng-routes.ts
+++ b/packages/angular/ssr/src/routes/ng-routes.ts
@@ -28,6 +28,7 @@ import { Console } from '../console';
 import { AngularAppManifest, getAngularAppManifest } from '../manifest';
 import { AngularBootstrap, isNgModule } from '../utils/ng';
 import { promiseWithAbort } from '../utils/promise';
+import { VALID_REDIRECT_RESPONSE_CODES, isValidRedirectResponseCode } from '../utils/redirect';
 import { addTrailingSlash, joinUrlParts, stripLeadingSlash } from '../utils/url';
 import {
   PrerenderFallback,
@@ -59,11 +60,6 @@ const CATCH_ALL_REGEXP = /\/(\*\*)$/;
  */
 const URL_PARAMETER_REGEXP = /(?<!\\):([^/]+)/g;
 
-/**
- * An set of HTTP status codes that are considered valid for redirect responses.
- */
-const VALID_REDIRECT_RESPONSE_CODES = new Set([301, 302, 303, 307, 308]);
-
 /**
  * Additional metadata for a server configuration route tree.
  */
@@ -163,7 +159,7 @@ async function* handleRoute(options: {
         includePrerenderFallbackRoutes,
       );
     } else if (redirectTo !== undefined) {
-      if (metadata.status && !VALID_REDIRECT_RESPONSE_CODES.has(metadata.status)) {
+      if (metadata.status && !isValidRedirectResponseCode(metadata.status)) {
         yield {
           error:
             `The '${metadata.status}' status code is not a valid redirect response code. ` +
diff --git a/packages/angular/ssr/src/utils/redirect.ts b/packages/angular/ssr/src/utils/redirect.ts
new file mode 100644
index 000000000000..7a65ff472a2a
--- /dev/null
+++ b/packages/angular/ssr/src/utils/redirect.ts
@@ -0,0 +1,46 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.dev/license
+ */
+
+/**
+ * An set of HTTP status codes that are considered valid for redirect responses.
+ */
+export const VALID_REDIRECT_RESPONSE_CODES = new Set([301, 302, 303, 307, 308]);
+
+/**
+ * Checks if the given HTTP status code is a valid redirect response code.
+ *
+ * @param code The HTTP status code to check.
+ * @returns `true` if the code is a valid redirect response code, `false` otherwise.
+ */
+export function isValidRedirectResponseCode(code: number): boolean {
+  return VALID_REDIRECT_RESPONSE_CODES.has(code);
+}
+
+/**
+ * Creates an HTTP redirect response with a specified location and status code.
+ *
+ * @param location - The URL to which the response should redirect.
+ * @param status - The HTTP status code for the redirection. Defaults to 302 (Found).
+ *                 See: https://developer.mozilla.org/en-US/docs/Web/API/Response/redirect_static#status
+ * @returns A `Response` object representing the HTTP redirect.
+ */
+export function createRedirectResponse(location: string, status = 302): Response {
+  if (ngDevMode && !isValidRedirectResponseCode(status)) {
+    throw new Error(
+      `Invalid redirect status code: ${status}. ` +
+        `Please use one of the following redirect response codes: ${[...VALID_REDIRECT_RESPONSE_CODES.values()].join(', ')}.`,
+    );
+  }
+
+  return new Response(null, {
+    status,
+    headers: {
+      'Location': location,
+    },
+  });
+}
diff --git a/packages/angular/ssr/test/app_spec.ts b/packages/angular/ssr/test/app_spec.ts
index 46b7cebc4e8a..ee88408410f9 100644
--- a/packages/angular/ssr/test/app_spec.ts
+++ b/packages/angular/ssr/test/app_spec.ts
@@ -12,7 +12,7 @@ import '@angular/compiler';
 /* eslint-enable import/no-unassigned-import */
 
 import { APP_BASE_HREF } from '@angular/common';
-import { Component, REQUEST, inject } from '@angular/core';
+import { Component, REQUEST, RESPONSE_INIT, inject } from '@angular/core';
 import { CanActivateFn, Router } from '@angular/router';
 import { AngularServerApp } from '../src/app';
 import { RenderMode } from '../src/routes/route-config';
@@ -33,6 +33,12 @@ describe('AngularServerApp', () => {
     })
     class RedirectComponent {
       constructor() {
+        const responseInit = inject(RESPONSE_INIT);
+        if (responseInit) {
+          // TODO(alanagius): Remove once https://github.com/angular/angular/pull/66126 is merged and released.
+          (responseInit as { status: number }).status = 308;
+        }
+
         void inject(Router).navigate([], {
           queryParams: { filter: 'test' },
         });
@@ -310,7 +316,7 @@ describe('AngularServerApp', () => {
       it('returns a 302 status and redirects to the correct location when `router.navigate` is used', async () => {
         const response = await app.handle(new Request('http://localhost/redirect-via-navigate'));
         expect(response?.headers.get('location')).toBe('/redirect-via-navigate?filter=test');
-        expect(response?.status).toBe(302);
+        expect(response?.status).toBe(308);
       });
 
       it('returns a 302 status and redirects to the correct location when `urlTree` is updated in a guard', async () => {