Cannot get an IdentityServer4 custom cookie handler working - identityserver4

Question

I'm unable to get a custom cookie authentication handler working with IdentityServer4. I'm using ASP.NET Core Identity and have followed the official guide: https://identityserver4.readthedocs.io/en/release/topics/signin.html
I need to override the CookieAuthenticationEvents.ValidatePrincipal and CookieAuthenticationEvents.SignedIn event handlers.
I've written a class that inherits CookieAuthenticationEvents and overrides the two event handlers.
I'm assigning it to a custom cookie handler via:
var auth = services.AddAuthentication("MyCookies");
auth.AddCookie("MyCookies", options =>
{
options.Events = new RealtimeStatusCookieAuthEvents(Configuration);
});
Here's my code:
https://gist.github.com/Amethi/f3411038a9447d274c0b721698fc5e63
The event handlers don't fire, i.e. I'm expecting them to fire for each request (due to ValidatePrincipal) and when I come back to the site after closing the browser and sign-in using cookie authentication (SignedIn).
Anyone know what I'm doing wrong?
Update:
Even simplifying it as follows doesn't help. The event handlers don't fire.
var auth = services.AddAuthentication("CustomCookies").AddCookie("CustomCookies", options =>
{
options.Events = new CookieAuthenticationEvents
{
OnSignedIn = context =>
{
Console.WriteLine("{0} - {1}: {2}", DateTime.Now,
"OnSignedIn", context.Principal.Identity.Name);
return Task.CompletedTask;
},
OnValidatePrincipal = context =>
{
Console.WriteLine("{0} - {1}: {2}", DateTime.Now,
"OnValidatePrincipal", context.Principal.Identity.Name);
return Task.CompletedTask;
},
};
});

Answer 1

I managed to make my custom cookie authentication handler work by using the ConfigureApplicationCookie extension.
builder.Services.ConfigureApplicationCookie(config =>
{
config.Cookie.Name = "IdentityServer.Cookie";
config.EventsType = typeof(CustomCookieAuthenticationHandler);
config.LoginPath = "/Account/Login";
});
And register the CustomCookieAuthenticationHandler handler
builder.Services.AddScoped<CustomCookieAuthenticationHandler>();
This is the handler implementation:
public class CustomCookieAuthenticationHandler: CookieAuthenticationEvents
{
private readonly IUserRepository _userRepository;
public CustomCookieAuthenticationEvents(IUserRepository userRepository)
{
_userRepository = userRepository;
}
public override Task ValidatePrincipal(CookieValidatePrincipalContext context)
{
// Your cookie authentication logic.
}
}
https://learn.microsoft.com/en-us/aspnet/core/security/authentication/cookie?view=aspnetcore-6.0