Identity Framework test if confirm email token is expired

Question

Is it possible to test whether a confirm email token is expired using Identity Framework\'s UserManager? No matter what the error is, from the following:

Answer 1

Here comes an .NET Core 2.1 adaption of the solution provided by @Nkosi :

ApplicationUser class

public class ApplicationUser : IdentityUser 
{
    public string EmailConfirmationToken { get; set; }
    public string ResetPasswordToken { get; set; }
}

Derived UserManager class

public class CustomUserManager : UserManager
{
    public CustomUserManager(IUserStore store, 
        IOptions optionsAccessor, 
        IPasswordHasher passwordHasher, 
        IEnumerable> userValidators, 
        IEnumerable> passwordValidators, 
        ILookupNormalizer keyNormalizer, 
        IdentityErrorDescriber errors, 
        IServiceProvider services, 
        ILogger> logger) 
        : base(store, optionsAccessor, passwordHasher, userValidators, passwordValidators, keyNormalizer, errors, services, logger)
    {

    }

    public override async Task GenerateEmailConfirmationTokenAsync(ApplicationUser user)
    {
        /* NOTE:
            * The default UserTokenProvider generates tokens based on the users's SecurityStamp, so until that changes
            * (like when the user's password changes), the tokens will always be the same, and remain valid. 
            * So if you want to simply invalidate old tokens, just call manager.UpdateSecurityStampAsync().
            */
        //await base.UpdateSecurityStampAsync(userId);

        var token = await base.GenerateEmailConfirmationTokenAsync(user);
        if (!string.IsNullOrEmpty(token))
        {
            user.EmailConfirmationToken = token; //<<< Last issued token
            //Note: If a token is generated then the current email is no longer confirmed.
            user.EmailConfirmed = false;
            await UpdateAsync(user);
        }
        return token;
    }

    public override async Task ConfirmEmailAsync(ApplicationUser user, string token)
    {
        if (user == null)
        {
            return IdentityResult.Failed(new IdentityError {Description = "User not found."});
        }
        var result = await base.ConfirmEmailAsync(user, token);
        if (result.Succeeded)
        {
            user.EmailConfirmationToken = null;
            return await UpdateAsync(user);
        }
        else if (user.EmailConfirmationToken == token)
        {
            //Previously Issued Token expired
            result = IdentityResult.Failed(new IdentityError { Description = "Expired token." });
        }
        return result;
    }

}

UserManager Extension

public static class ApplicationUserManagerExtension
{
    public static Task FindIdByEmailConfirmationTokenAsync(this UserManager manager, string confirmationToken)
    {
        string result = null;

        ApplicationUser user = manager.Users
            .SingleOrDefault(u => u.EmailConfirmationToken != null && u.EmailConfirmationToken == confirmationToken);

        if (user != null)
        {
            result = user.Id;
        }
        return Task.FromResult(result);
    }
}

Update: The CustomUserManager has to be added to services in Startup.cs in ConfigureServices Method.

services.AddTransient();

Without this, DependencyInjection fails.