UseStatusCodePagesWithReExecute with Blazor not working

[donnykwitty]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

• .NET 8 Blazor Web App Interactive Server Rendering
• Start with the standard template
• create a custom 404 page
• to program.cs, add app.UseStatusCodePagesWithReExecute("/404");

If this line is placed somewhere before app.UseStaticFiles(); then the content in "NotFound" element of the "Router" element is displayed --- not my custom 404 page.

If the line is placed somewhere after ap.UseStaticFiles() then you get this error:

InvalidOperationException: Endpoint /404 (/404) contains anti-forgery metadata, but a middleware was not found that supports anti-forgery.
Configure your application startup by adding app.UseAntiforgery() in the application startup code. If there are calls to app.UseRouting() and app.UseEndpoints(...), the call to app.UseAntiforgery() must go between them. Calls to app.UseAntiforgery() must be placed after calls to app.UseAuthentication() and app.UseAuthorization().

Anti-forgery is already configured, though.

Expected Behavior

I expect my custom 404 page to be displayed (along with a 404 status code being returned tot he client) when using UseStatusCodePagesWithReExecute

Steps To Reproduce

• .NET 8 Blazor Web App Interactive Server Rendering
• Start with the standard template
• create a custom 404 page
• to program.cs, add app.UseStatusCodePagesWithReExecute("/404");

Exceptions (if any)

InvalidOperationException: Endpoint /404 (/404) contains anti-forgery metadata, but a middleware was not found that supports anti-forgery.
Configure your application startup by adding app.UseAntiforgery() in the application startup code. If there are calls to app.UseRouting() and app.UseEndpoints(...), the call to app.UseAntiforgery() must go between them. Calls to app.UseAntiforgery() must be placed after calls to app.UseAuthentication() and app.UseAuthorization().

.NET Version

8

Anything else?

Visual Studio 2022

[nick4real]

Got the same issue. No workarounds?

[Sparkymod]

I encountered a similar issue while working with .NET 8 Blazor Web App Interactive Server Rendering. The problem arises from how middleware is ordered, especially when using app.UseStatusCodePagesWithReExecute in conjunction with authentication, authorization, and anti-forgery.

Solution:
To resolve this, I wrapped the UseStatusCodePagesWithReExecute middleware between UseAuthentication and UseAuthorization, and ensured that UseAntiforgery was correctly placed afterward. Here's how it work for me:

app.UseSerilogRequestLogging();

app.UseAuthentication();
app.UseRouting();

// Configure Razor Components with authorization
app.MapRazorComponents<App>().RequireAuthorization()
    .AddInteractiveServerRenderMode();

// Add the StatusCodePages middleware here
app.UseStatusCodePagesWithReExecute("/StatusCode/{0}");

app.UseAuthorization();

app.UseStaticFiles();
app.MapBlazorHub();

// Middleware to catch exceptions
app.UseExceptionCatcherMiddleware(false);

// Add user authentication
app.UseUser();

// Ensure Antiforgery is correctly applied
app.UseAntiforgery();

[donnykwitty]

@Sparkymod Dude, yes!!! It shouldn't be such a puzzle to piece this stuff together and have it work as expected. Thank you for this solution!