From Pluralsight/ASP.NET Core 6 Fundamentals

ASP.NET Core Identity

• A&A system that supports UI login functionality
• Not for APIs
• Supports external service providers
• Supports MVC & Razor Pages, scaffolding, SQL Server
• Includes a Razor Class Library for identity-enabled Views that typically need to be included in a web app

Important Classes

UserManager<IdentityUser>

Manages all interaction (CRUD operations) with user objects in the datastore.

SignInManager<IdentityUser>

User authentication and related actions; defines methods such as PasswordSignInAsync, ConfirmEmailAsync, SignOutAsync, etc.

Adding ASP.NET Core Identity to an App

Configuring

1. Add required packages
   dotnet add package microsoft.aspnetcore.identity.entityframeworkcore
dotnet add package microsoft.aspnetcore.identity.ui

2. Update the DbContext

   using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
   public class BethanysPieShopDbContext : IdentityDbContext // must inherit from this base class
   

   3. Add identity services to DI container Program.cs

   builder.Services.AddDefaultIdentity<IdentityUser>(options => // IdentityUser is a built-in type to represent a user
   { 
       // registration will only succeed if these conditions are met:
       options.Password.RequireDigit = true;
       options.Password.RequiredLength = 8;
       options.Password.RequireNonAlphanumeric = true;
       options.User.RequireUniqueEmail = true;
   })
   .AddEntityFrameworkStores<BethanysPieShopDbContext>(); // use EF for identity data
   

3. Add authentication middlewareZ

   app.UseAuthentication();
   

4. Run a build

5. Create a migration Creates an ASP.NET Roles, Users, RoleClaims, UserClaims, UserLogins, and other tables: pmc > add-migration IdentityAdded
   pmc > update-database

Adding Authentication

Two techniques: manual approach or scaffolding

Scaffolding

1. Right-click project > Add > New Scaffolded Item… > Identity > Add > check Override all files OR check specific items > Data context class: SomeDbContext > Add This will, among other things, make changes to Program.cs.
   Adds:
   Areas > Identity > Pages >
   _ValidationScriptsPartial.cshtml, _ViewImports.cshtml, _ViewStart.cshtml
Account >
   _ViewImports.cshtml
Login.cshtml — the Login UI
   Register.cshtml — the UI to register a new account

2. Update layout to account for scripts that scaffolding added:
   /Views/Shared/_Layout.cshtml
   Below @RenderBody()
@RenderSection("Scripts", required: false)

3. Update layout to add the login partial:
   /Views/Shared/_Layout.cshtml

       <partial name="_LoginPartial" />
   

Adding Authorization

1. Add authorization middleware:
   Program.cs

   app.UseAuthorization();
   

2. Decorate Controller and/or Action(s) with Authorize attribute
   [Authorize] attribute
   - Can be added to Controller to a Controller’s Action - Confirms user is logged in before proceeding

   [Authorize(Roles = "RoleGroup")] - Checks if user is logged in AND if user is part of RoleGroup before proceeding

   Example

   [Authorize]
   public class OrderController : Controller
   {
       [Authorize] // requires user to be logged in to use this method
       public IActionResult Checkout()
       {
       }
   }