HttpNavigationManager no longer uses NavigationException

src/Components/Endpoints/src/DependencyInjection/HttpNavigationManager.cs

@@ -7,11 +7,29 @@ namespace Microsoft.AspNetCore.Components.Endpoints;
 
 internal sealed class HttpNavigationManager : NavigationManager, IHostEnvironmentNavigationManager
 {
+    private const string EnableThrowNavigationException = "Microsoft.AspNetCore.Components.Endpoints.HttpNavigationManager.EnableThrowNavigationException";
+    private static bool ThrowNavigationException =>
+        AppContext.TryGetSwitch(EnableThrowNavigationException, out var switchValue) && switchValue;
+
+    private EventHandler<NavigationEventArgs>? _onNavigateTo;
+    public event EventHandler<NavigationEventArgs> OnNavigateTo
+    {
+        add => _onNavigateTo += value;
+        remove => _onNavigateTo -= value;
+    }
+
     void IHostEnvironmentNavigationManager.Initialize(string baseUri, string uri) => Initialize(baseUri, uri);
 
     protected override void NavigateToCore(string uri, NavigationOptions options)
     {
         var absoluteUriString = ToAbsoluteUri(uri).AbsoluteUri;
-        throw new NavigationException(absoluteUriString);
+        if (ThrowNavigationException)
+        {
+            throw new NavigationException(absoluteUriString);
+        }
+        else
+        {
+            _onNavigateTo?.Invoke(this, new NavigationEventArgs(absoluteUriString));
+        }
     }
 }

src/Components/Endpoints/src/DependencyInjection/NavigationEventArgs.cs

@@ -0,0 +1,14 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Components.Endpoints;
+
+internal class NavigationEventArgs : EventArgs
+{
+    public string Uri { get; }
+
+    public NavigationEventArgs(string uri)
+    {
+        Uri = uri;
+    }
+}

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs

@@ -84,6 +84,10 @@ internal async Task InitializeStandardComponentServicesAsync(
         if (navigationManager != null)
         {
             navigationManager.OnNotFound += SetNotFoundResponse;
+            if (navigationManager is HttpNavigationManager httpNavigationManager)
+            {
+                httpNavigationManager.OnNavigateTo += OnNavigateTo;
+            }
         }
 
         var authenticationStateProvider = httpContext.RequestServices.GetService<AuthenticationStateProvider>();
@@ -135,6 +139,11 @@ internal async Task InitializeStandardComponentServicesAsync(
         }
     }
 
+    private void OnNavigateTo(object? sender, NavigationEventArgs args)
+    {
+        _httpContext.Response.Redirect(args.Uri);
+    }
+
     private static void InitializeResourceCollection(HttpContext httpContext)
     {
 

src/Components/test/E2ETest/ServerRenderingTests/NoInteractivityTest.cs

@@ -64,4 +64,16 @@ public void CanUseServerAuthenticationStateByDefault()
         Browser.Equal("True", () => Browser.FindElement(By.Id("is-in-test-role-1")).Text);
         Browser.Equal("True", () => Browser.FindElement(By.Id("is-in-test-role-2")).Text);
     }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void NavigatesWithoutInteractivityByRequestRedirection(bool controlFlowByException)
+    {
+        AppContext.SetSwitch("Microsoft.AspNetCore.Components.Endpoints.EnableThrowNavigationException", isEnabled: controlFlowByException);
+        Navigate($"{ServerPathBase}/routing/ssr-navigate-to");
+        Browser.Equal("Click submit to navigate to home", () => Browser.Exists(By.Id("test-info")).Text);
+        Browser.Click(By.Id("redirectButton"));
+        Browser.Equal("Routing test cases", () => Browser.Exists(By.Id("test-info")).Text);
+    }
 }

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/RoutingTestCases.razor

@@ -1,5 +1,5 @@
 @page "/routing"
-<h3>Routing test cases</h3>
+<h3 id="test-info">Routing test cases</h3>
 
 <ul>
     <li>
@@ -24,12 +24,6 @@
         <a href="routing/complex-segment(value)">Complex segments</a>
     </li>
     <li>
-        <a href="routing/not-found-ssr">Not found page for Static Server Rendering</a>
-    </li>
-    <li>
-        <a href="routing/not-found-webassembly">Not found page for Interactive WebAssembly rendering</a>
-    </li>
-    <li>
-        <a href="routing/not-found-server">Not found page for Interactive Server rendering</a>
+        <a href="routing/ssr-navigate-to">Redirect on SSR page</a>
     </li>
 </ul>

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/SSRRedirection.razor

@@ -0,0 +1,17 @@
+@page "/routing/ssr-navigate-to"
+@using Microsoft.AspNetCore.Components.Forms
+@inject NavigationManager NavigationManager
+
+<p id="test-info">Click submit to navigate to home</p>
+<form method="post" @onsubmit="Submit" @formname="MyUniqueFormName">
+    <AntiforgeryToken />
+    <button type="submit" id="redirectButton" class="btn btn-primary">Redirect</button>
+</form>
+
+@code {
+    private void Submit()
+    {
+        NavigationManager.NavigateTo("/subdir/routing");
+    }
+}
+