Blazor Server App with Azure AD authentication - Token expired and Custom AuthenticationStateProvider - azure

Question

I have built a Blazor Server App with Azure AD authentication. This server app access a web api written in net core and sends the JWT token to that api. Everything is working, data is gathered, page is displayed accordingly.
The problem is: after some time, when user interacts with some menu option in UI, nothing else is returned from webapi. After some tests I found out that the token has expired, then when it is sent to web api, it is not working. But the AuthenticationState remains same, like it is authenticated and valid irrespective the token is expired.
Thus, I have been trying some suggestions like : Client side Blazor authentication token expired on server side. Actually it is the closest solution I got.
But the problem is that, after implemented a CustomAuthenticationStateProvider class, even after injected it, the default AuthenticationStateProvider of the app remains like ServerAuthenticationStateProvider and not the CustomAuthenticationStateProvider I have implemented. This is part of my code:
public class CustomAuthenticationStateProvider : AuthenticationStateProvider
{
private readonly IConfiguration _configuration;
private readonly ITokenAcquisition _tokenAcquisition;
public CustomAuthenticationStateProvider(IConfiguration configuration, ITokenAcquisition tokenAcquisition)
{
_configuration = configuration;
_tokenAcquisition = tokenAcquisition;
}
public override async Task<AuthenticationState> GetAuthenticationStateAsync()
{
var apiScope = _configuration["DownloadApiStream:Scope"];
var anonymousState = new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity()));
string savedToken = string.Empty;
try
{
savedToken = await _tokenAcquisition.GetAccessTokenForUserAsync(new[] { apiScope });
}
catch (MsalUiRequiredException)
{
savedToken = string.Empty;
}
catch (Exception)
{
savedToken = string.Empty;
}
if (string.IsNullOrWhiteSpace(savedToken))
{
return anonymousState;
}
var claims = ParseClaimsFromJwt(savedToken).ToList();
var expiry = claims.Where(claim => claim.Type.Equals("exp")).FirstOrDefault();
if (expiry == null)
return anonymousState;
// The exp field is in Unix time
var datetime = DateTimeOffset.FromUnixTimeSeconds(long.Parse(expiry.Value));
if (datetime.UtcDateTime <= DateTime.UtcNow)
return anonymousState;
return new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity(claims, "jwt")));
}
public void NotifyExpiredToken()
{
var anonymousUser = new ClaimsPrincipal(new ClaimsIdentity());
var authState = Task.FromResult(new AuthenticationState(anonymousUser));
NotifyAuthenticationStateChanged(authState);
}
private IEnumerable<Claim> ParseClaimsFromJwt(string jwt)
{
var claims = new List<Claim>();
var payload = jwt.Split('.')[1];
var jsonBytes = ParseBase64WithoutPadding(payload);
var keyValuePairs = JsonSerializer.Deserialize<Dictionary<string, object>>(jsonBytes);
keyValuePairs.TryGetValue(ClaimTypes.Role, out object roles);
if (roles != null)
{
if (roles.ToString().Trim().StartsWith("["))
{
var parsedRoles = JsonSerializer.Deserialize<string[]>(roles.ToString());
foreach (var parsedRole in parsedRoles)
{
claims.Add(new Claim(ClaimTypes.Role, parsedRole));
}
}
else
{
claims.Add(new Claim(ClaimTypes.Role, roles.ToString()));
}
keyValuePairs.Remove(ClaimTypes.Role);
}
claims.AddRange(keyValuePairs.Select(kvp => new Claim(kvp.Key, kvp.Value.ToString())));
return claims;
}
private byte[] ParseBase64WithoutPadding(string base64)
{
switch (base64.Length % 4)
{
case 2: base64 += "=="; break;
case 3: base64 += "="; break;
}
return Convert.FromBase64String(base64);
}
}
This is my Program.cs where I added the services :
builder.Services.AddScoped<CustomAuthenticationStateProvider>();
builder.Services.AddScoped<AuthenticationStateProvider>(provider => provider.GetRequiredService<CustomAuthenticationStateProvider>());
Here in the MainLayou.razor, I inject the service and try to use it :
#inject CustomAuthenticationStateProvider authenticationStateProvider;
protected async override Task OnInitializedAsync()
{
var authState = await authenticationStateProvider.GetAuthenticationStateAsync();
if (authState.User?.Identity == null || !authState.User.Identity.IsAuthenticated)
{
authenticationStateProvider.NotifyExpiredToken();
}
await base.OnInitializedAsync();
}
The problem comes up here, because the authenticationStateProvider is not an instance of the CustomAuthenticationStateProvider , but the instance of ServerAuthenticationStateProvider. It is like AuthenticationStateProvider was not replaced by the custom implementation, therefore I can't use the NotifyAuthenticationStateChanged and inform the CascadingAuthenticationState that it was changed.
If anyone has already been thru this or have any suggestion, it would be appreciated.
Actually I just wanna to change authentication state to not authenticated. So user will be pushed to login again using Azure AD.
Thanks