Dot Net 8+ NotFound behavior

[nw5428]

This is in reference to #48983

My requirements are to display a user friendly not found page for any path that does not have a specified route and do not redirect which updates the URI. We did not realize that Dot Net 8 changed this behavior.

After trying 18 different things, finally tried adding the below in program.cs between builder.Build and calls to UseAuthentication / UseAuthorization which appears to work perfectly.

app.UseStatusCodePagesWithReExecute("/");

//We do not want reexecute for anything in our api calls
app.Use(async (context, next) =>
{

    if (context.Request.Path.StartsWithSegments("/api", StringComparison.OrdinalIgnoreCase))
    {
        var statusCodeFeature = context.Features.Get<IStatusCodePagesFeature>();

	if (statusCodeFeature != null && statusCodeFeature.Enabled)
	{
		statusCodeFeature.Enabled = false;
	}
    }

    await next();
});

app.UseWhen(context => context.Request.Path.StartsWithSegments("/api"), (appBuilder) =>
{
appBuilder.UseProblemDetails();
});

This ends up reverting the behavior to functionally do the same thing it did in .net 7. It will use the in the main blazor router. The other suggestions mentioned are ok but they do not retain the original URL in the browser.

I think the documentation should be updated to notate this option and the feature retained in future releases.

I think it also makes sense to instead have an option that is more obvious such as:

app.MapRazorComponents(options => options.FallbackOnNotFound("/"));

[garrettlondon1]

I believe the documentation was updated, where "NotFound" is no longer used and has to go through standard middleware

[nw5428]

yeah I saw that. I disagree with the assessment and think there should be an easier way to handle it, which I proposed.

[javiercn]

@nw5428 thanks for contacting us.

We are doing work in this area in .NET 10.0, but we aren't bringing back the fallback endpoint as that causes a whole set of different problems.

Our plan includes supporting a NotFound @page that can be used with UseStatusCodePagesWithReExecute and that also works on interactive scenarios.

[nw5428]

Sounds good. Thanks