RevalidatingAuthenticationStateProvider.cs

public class RevalidatingAuthenticationStateProvider : AuthenticationStateProvider, IDisposable
{
    private static TimeSpan RefreshInterval = TimeSpan.FromMinutes(30);

    private readonly CancellationTokenSource _cts;
    private ClaimsPrincipal _currentUser;

    public RevalidatingAuthenticationStateProvider(SignInManager<IdentityUser> signInManager)
    {
        _cts = new CancellationTokenSource();
        _currentUser = signInManager.Context.User;
        _ = RefreshLoop(_cts.Token, signInManager);
    }

    private async Task RefreshLoop(CancellationToken cancellationToken, SignInManager<IdentityUser> signInManager)
    {
        while (true)
        {
            await Task.Delay(RefreshInterval, cancellationToken);
            if (cancellationToken.IsCancellationRequested)
            {
                break;
            }

            try
            {
                // Rebuild user data using latest info from Identity DB
                var identityUser = await signInManager.UserManager.GetUserAsync(_currentUser);
                _currentUser = await signInManager.CreateUserPrincipalAsync(identityUser);
            }
            catch
            {
                // If anything goes wrong, just log them out
                _currentUser = new ClaimsPrincipal();
                _cts.Cancel();
            }

            NotifyAuthenticationStateChanged(GetAuthenticationStateAsync());
        }
    }

    public override Task<AuthenticationState> GetAuthenticationStateAsync()
        => Task.FromResult(new AuthenticationState(_currentUser));

    public void Dispose()
        => _cts.Cancel();
}