Need advice of where to put custom user authorization in ASP.NET Core - asp.net

Question

I need advice of where to put custom user authorization code in ASP.NET Core. I am somewhat a ASP.NET Framework developer and normally I will add code to Global.asax as a session_onstart event to look up a SQL table where users profile are stored that is used to determine what they can view in the rest of the application. With Global.asax this is only cause once per user session, so what I would like to do is the same kind of approach in ASP.NET Core which I am kind of new to but need advice where that check should be done

Answer 1

I would like to do is the same kind of approach in ASP.NET Core which
I am kind of new to but need advice where that check should be done
Well, based on your description, in asp.net core you can achieve that in many ways. For instances, you could set in following places:
program.cs/startup.cs files
Using Middleware file
Using Action Filter
Let's, consider below example using action filter
Role and permissison:
First we are defining the role and the permission.
public enum Role
{
User,
Admin,
SuperAdmin
}
public enum Permission
{
Read,
Create,
Update,
Delete
}
Authorization On Action Filter:
public class AuthorizeActionFilter : IAuthorizationFilter
{
private readonly Role _role;
private readonly Permission _permission;
public AuthorizeActionFilter(Role item, Permission action)
{
_role = item;
_permission = action;
}
public void OnAuthorization(AuthorizationFilterContext context)
{
var isAuthorized = context.HttpContext.User.Claims.Any(c => c.Type == _role.ToString() && c.Value == _permission.ToString());
if (!isAuthorized)
{
context.Result = new ForbidResult();
}
}
}
Note: Check your user claim from the HttpContext if that containts either Admin or Read authorization.
Controller:
[Authorize(Role.User, Permission.Read)]
public IActionResult MemberList()
{
var memberList = _context.Members.ToList();
return View(memberList);
}
Output:
You even can implement that using Middleware. Asp.net 6 now providing couple of other mechanism now a days, you could have a look below official implementations as well.
Role-based authorization
Claims-based authorization
Policy-based authorization
Custom Action Filter