ASp.net core 3.1 identity

It is just an extension to cookie authentication. We get a UI, Tables, helper classes, two factor authentication etc. Even EF and its database constructs.

So instead of writing code for all of this we can just use these in built features.

Extending Default Identity Classes

Add a class that inherits from 

 public class AppUser : IdentityUser

    {

        public string Behavior { get; set; }

    }

Also change the user type in login partial.cs under shared folder

Then add migrations and update db using migrations. We can customize further.

 services.AddDefaultIdentity<AppUser>(options => 

            {

                options.SignIn.RequireConfirmedAccount = true;

                options.Password.RequireDigit = false;

            })

   .AddEntityFrameworkStores<ApplicationDbContext>(); -- Tells Identity to use this context.

 app.UseAuthentication(); -- configures cookie  based auth 

Identities UI

No UI pages are there in the project instead its in a nuget package.

Adding Identity to existing project

A text file named ScaffoldingReadMe.txt will be created.  Follow all the instructions and make the changes. The new DBContext will be added in the Areas folder and connection string will be added to the appsettings.json file.

IdentityHostingStartup.cs . This class works as a combination of both configure and configureservices inside startup.cs. We can copy them to startup also if needed. This class is called everytime the application starts. Also check out these files.

The razor pages dont have a controller, the code is in written as codebehind. In order to add more claims to the ClaimsPrincipal or to return more claims in the cookie, just add the new claims to the aspnetclaims table. Or 


public class AppNewUserCLaims : UserClaimsPrincipalFactory<ConfArchWebUser>
    {
        public AppNewUserCLaims(UserManager<ConfArchWebUser> userManager, IOptions<IdentityOptions> options)
            : base(userManager, options) => (_userManager, _options) = (userManager, options);

        public UserManager<ConfArchWebUser> _userManager { get; }
        public IOptions<IdentityOptions> _options { get; }

        protected override async Task<ClaimsIdentity> GenerateClaimsAsync(ConfArchWebUser user)
        {
            var identity = await base.GenerateClaimsAsync(user);

            // Add custom claims to the cookie
            identity.AddClaim(new Claim("FullName", user.FullName));

            return identity;

        }

    }


Inject it into the container.

 services.AddScoped<IUserClaimsPrincipalFactory<ConfArchWebUser>, AppNewUserCLaims>();

Or while creating a new User just add the claims to the AspnetClaims table, this will be included by default..

ROLES

Roles are added as claims. So if a user has 2 roles then they will be added to the claims lists

1.Add role to AspNetRoles

2. Asoociate that role to a user in AspNetUserRoles

EXTERNAL LOGINS

For external logins we can just add to IdentityHostingStartup

services.AddAuthentication()
                .AddGoogle(options =>
                {
                    options.ClientId = "xxxxxx";
                    options.ClientSecret = "xxxxxxxxxx";
                });

We can link local logins to google logins.