How to make a single admin user for MVC .Net Core app

Question

I'm building a web app that is essentially a store, but I want to put in an easy way for the admin of the site to add new products. However I want to restrict this part of the site so only the admin can access it. I have no use for other users at this moment.

How do I make it so that anybody with the admin username and password can access these pages and it will persist to know that they are logged in? I already have a system in place that accepts a user input and then continues to the admin pages if it's correct. But the problem is if someone decides to just go directly to the pages like Admin/AddProduct. I'd need my app to know that they're not allowed to access the AddProduct page yet and redirect them back to the login.

Answer 1

Here's how you go about it Joey

You could do this easily by creating a CreateRoles method in your startup class. This helps check if the roles are created, and creates the roles if they aren't; on application startup. Like so.

private async Task CreateRoles(IServiceProvider serviceProvider)
    {
        //initializing custom roles 
        var RoleManager = serviceProvider.GetRequiredService<RoleManager<IdentityRole>>();
        var UserManager = serviceProvider.GetRequiredService<UserManager<ApplicationUser>>();
        string[] roleNames = { "Admin", "Store-Manager", "Member" };
        IdentityResult roleResult;

        foreach (var roleName in roleNames)
        {
            var roleExist = await RoleManager.RoleExistsAsync(roleName);
            // ensure that the role does not exist
            if (!roleExist)
            {
                //create the roles and seed them to the database: 
                roleResult = await RoleManager.CreateAsync(new IdentityRole(roleName));
            }
        }

        // find the user with the admin email 
        var _user = await UserManager.FindByEmailAsync("[email protected]");

       // check if the user exists
       if(_user == null)
       {
            //Here you could create the super admin who will maintain the web app
            var poweruser = new ApplicationUser
            {
                UserName = "Admin",
                Email = "[email protected]",
            };
            string adminPassword = "p@$$w0rd";

            var createPowerUser = await UserManager.CreateAsync(poweruser, adminPassword);
            if (createPowerUser.Succeeded)
            {
                //here we tie the new user to the role
                await UserManager.AddToRoleAsync(poweruser, "Admin");

            }
       }
    }

and then you could call the await CreateRoles(serviceProvider); method from the Configure method in the Startup class. ensure you have IServiceProvider as a parameter in the Configure class.

Question 2: "How do I make it so that anybody with the admin username and password can access these pages "

You can do this easily, like so.

[Authorize(Roles="Admin")]
public class ManageController : Controller
{
   //....
   Return View();
}

You can also use role-based authorization in the action method like so. Assign multiple roles, if you will

[Authorize(Roles="Admin")]
public IActionResult Index()
{
/*
 .....
 */ 
}

While this works fine, for a much better practice, you might want to read about using policy based role checks. You can find it on the ASP.NET core documentation here, or this article I wrote about it here

Answer 2

Once you add ASP.NET Identity to your project you can implement Role based Authorization in your application. Basically it allows you to setup [Authorize(Roles = "Administrator")] attribute for contollers which shall be available for admin users only.