How to not make the user re-login every time browser closes? - asp.net-mvc

Question

This might be a basic/dumb question, but I don't know the right keyword to Google. What I want is that when I authenticate the user to my web app, they can close the browser, and when they open it back, they can still use my website - they are not logged out (yet).
I have been following the tutorials in IdentityServer docs (https://identityserver4.readthedocs.io/en/latest/quickstarts/2_interactive_aspnetcore.html), and so far I have managed to get the whole IDP-API-Client working. I have inspect the token that I get from IDP, it's valid for 2 weeks, so what am I missing here, why do I get logged out when I close the browser?
My guess is that I need to store the token to the cookie, but how do I save it, and how do I force the web application to always check for the cookie?
The IS4 tutorial has this:
services.AddAuthentication(o =>
{
o.DefaultScheme = "Cookies";
o.DefaultChallengeScheme = "oidc";
})
.AddCookie("Cookies")
.AddOpenIdConnect("oidc", o =>
{
o.Authority = "https://localhost:5001";
o.ClientId = "mymvcclient";
o.ClientSecret = "mymvcclientsecret";
o.ResponseType = "code";
o.SaveTokens = true;
o.Scope.Add("myapi");
o.Scope.Add("offline_access");
});
I assume that's just creating a cookie, but how do I specify for it to save my token, and read the token from the cookie when user opens my web application?

Answer 1

Yea there is an option called ExpireTimeSpan in your cookie handler, which defaults to 14 days. You can change it to anytime longer than that by just setting a value to it:
...
.AddCookie("Cookies", options => {
options.ExpireTimeSpan = TimeSpan.FromDays(30);
options.SlidingExpiration = false;
})
.AddOpenIdConnect("oidc", options => {
...
options.UseTokenLifetime = false;
...
})...
The above sets the cookie expiration to 30 days, instead of the default 2 weeks.
You also want to make sure the UseTokenLifetime option from the OIDC is set to false, which is the default for now I think. Tokens coming back from the Identity Server, for example, tend to have short lives. If you set it to true, which was default before, then it would override whatever expiration you set earlier.

Answer 2

The best term to look for on this is probably "persistent sessions", or just session management in general. This is something handled by ASP.NET Core, not really IdentityServer. There are several mechanisms to maintain session state on the server, which you'd need for example not to lose all sessions when a server restart happens.
I've had the best luck using the ITicketStore interface, which allows persisting the sessions to a database. The cookie ends up with a session ID which is validated on each request for expiration.