Angular with zoneless and SSR - redirectTo issue

[zedL-io]

Which @angular/* package(s) are the source of the bug?

router

Is this a regression?

Yes

Description

Problem Description
When configuring a redirect route in an Angular 19 application using Server-Side Rendering (SSR) and zoneless mode, an issue arises when accessing the app through the entry (root) route. In this scenario, the server returns an empty response, but the application works fine for other routes. The issue only occurs when navigating to the redirect route defined in the app.routes.ts configuration.

Steps to Reproduce:
Clone repo and install npm packages.

Configure a redirect route in app.routes.ts. (i found a working solution with a redirectGuard, you can switch)

Start the application in SSR mode. (ng serve --no-hmr)

Access the application via the entry route (root).

The server returns a blank response instead of properly redirecting.

Navigation to other routes works as expected.

Expected Behavior:
The server should correctly handle the redirect and return the appropriate content or redirect response when accessing the redirect route.

Actual Behavior:
The server returns a blank or empty response when navigating to the redirect route from the entry point. Other routes function as expected.

Please provide a link to a minimal reproduction of the bug

https://github.com/zedL-io/ng-19-zoneless-ssr-redirect-issue

Please provide the exception or error you saw

The Express server return a document with content-length:0.

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 19.2.5
Node: 22.13.0
Package Manager: npm 11.1.0
OS: win32 x64

Angular: 19.2.4
... common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, platform-server
... router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1902.5
@angular-devkit/build-angular   19.2.5
@angular-devkit/core            19.2.5
@angular-devkit/schematics      19.2.5
@angular/cli                    19.2.5
@angular/ssr                    19.2.5
@schematics/angular             19.2.5
rxjs                            7.8.2
typescript                      5.7.3

Anything else?

I found a working solution for me with a route guard.
// { path: '', canActivate: [redirectGuard], children: [] }, // this work!
Comment out the redirect route and use this one to get it to work.

[alan-agius4]

The issue is coming from the customization of the server.ts handler, which is causing improper handling of redirects. Additionally, the Response object from angularApp.handle is not being correctly augmented or reused. To properly transform the web request into a Node request, use writeResponseToNodeResponse. If modifications to the web response are needed, you can leverage the available methods or clone the response to create a new one when updating the body.

See: https://developer.mozilla.org/en-US/docs/Web/API/Response

[zedL-io]

@alan-agius4 Thank you very mutch. I updated the server.ts and now it works for me. Whats with having CSP in the server.ts by default? It is such an important topic.