I have an Mulit-tenant application using KeyCloak as Identity Broker.
There is TenantId in token through which , we will be able to identity which Tenant’s user it is.
Now, when authenticating the token, we use AddJwtBearer with Authority.
I want that Authority to be fetched from configuration based on TenantId.

Is there any way to achieve this?

public static class KeycloakAuthenticationExtensions

{
public static void AddKeycloakAuthentication(this IServiceCollection services, IConfiguration configuration)
{
var jwtConfiguration = configuration.GetSection(Core.Authentication.Constants.JwtConfigurationSection).Get();

    services.AddOptions<JwtConfiguration>().Bind(configuration.GetSection(Authentication.Constants.JwtConfigurationSection));
    services.AddAuthentication(options =>
    {
        options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
        options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;

    }).AddJwtBearer(options =>
    {
        options.Authority = jwtConfiguration!.Authority;
        options.SaveToken = false;
        options.TokenValidationParameters = new Microsoft.IdentityModel.Tokens.TokenValidationParameters
        {
            ValidAudiences = jwtConfiguration.Audiences,
            ValidateAudience = true,
            ValidateIssuer = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            //https://learn.microsoft.com/en-us/aspnet/core/security/authentication/claims?view=aspnetcore-6.0#extend-or-add-custom-claims-using-iclaimstransformation
            //Name claim and role claim mapping
            NameClaimType = ApiConstants.PreferredUserNameClaim
        };

        options.Events = new JwtBearerEvents()
        {
            OnMessageReceived = context =>
            {
                return Task.CompletedTask;
            },
            OnAuthenticationFailed = context =>
            {
                context.Response.StatusCode = StatusCodes.Status401Unauthorized;
                return context.Response.WriteAsync(context.Request.Headers[ApiConstants.AuthorizationHeader].ToString());
            },
            OnTokenValidated = context =>
            {
                return Task.CompletedTask;
            }
        };

    });
    services.AddSingleton<ITokenProvider, KeyCloakJwtTokenProvider>();
    services.AddSingleton<ITokenStore, InMemoryCachedTokenStore>();
    services.AddTransient<AuthenticationHttpMessageHandler>();
    services.AddHttpClient<ITokenProvider, KeyCloakJwtTokenProvider>(client =>
    {
        client.BaseAddress = new Uri(jwtConfiguration!.Authority + ApiConstants.TokenEndpoint);
    });
}

}

I have changed that jwtConfiguration to be a list of Tenants information.

For each request , AddJwtBearer is called to validate the token. Based on tenant Id coming as part of token I want to Set Authority and validate the token.