Blazor app not using Exception Filter

[jasonshave]

I have a server-side Blazor application I'd like to use a custom Exception Filter for as per: https://docs.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-3.1#exception-filters.

Are these filters supported in a Blazor application?

Describe the bug

I'm trying to use the Microsoft.Identity.Web library and MSAL.NET to authenticate to the MSFT Graph. In this library there is a need to throw a MsalUiRequiredException and for a custom handler to deal with obtaining a new token. This issue is that I can't get my Blazor application, which right now is just the default template, to throw and catch the exception using the custom filter I created.

Perhaps this is simply an issue with how the filter is being applied or maybe it's not supported yet, I don't know which one it is.

To Reproduce

Create a new Blazor server-side application and attempt to implement the same Exception Filter from the link above. I've tried to implement the filter in two different ways:

1. Applying the filter in Startup.cs by specifying the AuthorizeForScopesAttribute as such:

services.AddControllersWithViews(options => { var policy = new AuthorizationPolicyBuilder() .RequireAuthenticatedUser() .Build(); options.Filters.Add(new AuthorizeFilter(policy)); options.Filters.Add(new AuthorizeForScopesAttribute(new[] {ScopeConstants.ScopeUserRead})); });

2. Decorating the partial view class using the method described in the docs article.

Set a breakpoint and throw a new exception. The breakpoint is never hit.

Further technical details

.NET Core SDK (reflecting any global.json):
Version: 3.1.101
Commit: b377529961

Runtime Environment:
OS Name: Windows
OS Version: 10.0.18362
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\3.1.101\

Host (useful for support):
Version: 3.1.1
Commit: a1388f194c

.NET Core SDKs installed:
3.1.101 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

[javiercn]

@jasonshave thanks for contacting us.

Exception filters are not part of the Blazor programming model and are not supported. See this link for details on error handling in Blazor applications.