How to setup password expiration using ASP.NET Identity Framework

Question

I have a ASP.NET project using Identity. For Identity Configuration regarding passwords, the PasswordValidator is being used. How do I expand the enforcement of

Answer 1

There is no such functionality builtin ASP.NET Identity 2. Easiest is to add a field on the user like LastPasswordChangedDate. And then check this field during each Authorization.

public class ApplicationOAuthProvider : OAuthAuthorizationServerProvider
{
    public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
    {
        var user = await GetUser(context.UserName, context.Password);
        if(user.LastPasswordChangedDate.AddDays(20) < DateTime.Now)
           // user needs to change password

    }
}