📓 3.5.0.4 Identity Setup and Configuration

In this lesson, we'll add Identity to our To Do List application. This will involve creating a new class to manage user accounts with Identity, updating our Program.cs to include Identity in our project, and configuring Identity to work with Entity Framework Core. You can follow this same process to add Identity to any of your projects.

Identity Setup and Configuration

---

Start by opening up your To Do List app. We'll continue where we left off from section 4. That corresponds to the code in the branch 6_data_from_multiple_db_tables in the section 4 example repo for the To Do List app.

Since we're embarking on a new version of our project, we recommend creating and using a new branch as well as updating appsettings.json to use a new database name. For example, to_do_list_with_auth — that's what we'll use in our example projects. When you update to a new database name, don't forget to create the database with the command dotnet ef database update.

ToDoList/appsettings.json

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=localhost;Port=3306;database=to_do_list_with_auth;uid=root;pwd=epicodus;"
  }
}

Creating a User class by Extending an Identity Class

Let's start by creating a class to represent user accounts. Fortunately, Identity comes with a class to represent users called IdentityUser. As we can see in the documentation on the IdentityUser class, this class contains a number of properties such as Email, UserName, and many others, like the number of recorded failed login attempts.

We'll implement the functionality in the IdentityUser class by creating our own custom class that extends from IdentityUser.

Add a file named ApplicationUser.cs to Models. It should contain the following code:

Models/ApplicationUser.cs

using Microsoft.AspNetCore.Identity;

namespace ToDoList.Models
{
    public class ApplicationUser : IdentityUser
    {

    }
}

We extend Identity's IdentityUser class into our own custom ApplicationUser class using the : operator in the class declaration. This ensures our ApplicationUser class inherits all necessary functionality from Identity's IdentityUser class.

Note — we don't have to create our own custom ApplicationUser class! We could have simply used Identity's IdentityUser class and not gone through the trouble of creating a new model. However, when we create our own custom class (that inherits from IdentityUser), we can add new properties to it. For example, what if we want to allow users to have a profile picture? Or list their personal website? Or save their birthday? We could add properties for each of those. Here's an example:

using Microsoft.AspNetCore.Identity;
using System;

namespace ToDoList.Models
{
    public class ApplicationUser : IdentityUser
    {
      public string Website { get; set; }
      public string Image { get; set; }
      public DateOnly Birthday { get; set; }
    }
}

And with the above example configuration, our ApplicationUser class will have Website, Image, and Birthday properties along with all of the properties listed in the IdentityUser class.

We won't be adding properties to our custom ApplicationUser class in our To Do List application, but you definitely should explore doing so in your own projects.

Configuring Identity to Work with Entity Framework Core

Identity is built to use Entity Framework Core and store user information in a database. It comes with the class IdentityDbContext, which extends EF Core's DbContext class to work with user authentication.

First, we'll need to include the package that connects the two:

$ dotnet add package Microsoft.AspNetCore.Identity.EntityFrameworkCore -v 6.0.0

We'll now see Microsoft.AspNetCore.Identity.EntityFrameworkCore added to our package list in ToDoList.csproj.

We'll update ToDoListContext.cs so that it extends from IdentityDbContext instead of DbContext.

Models/ToDoListContext.cs

using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;

namespace ToDoList.Models
{
    public class ToDoListContext : IdentityDbContext<ApplicationUser>
    {
      // Don't change code in here.
    }
}

• We'll have to add a new using directive: using Microsoft.AspNetCore.Identity.EntityFrameworkCore;

• Once again, we extend a class with the : operator. We're instructing our ToDoListContext class to inherit all functionality from Identity's built-in IdentityDbContext class. This replaces the DbContext class that ToDoListContext was previously extending from.

• Notice that we're declaring ApplicationUser as the type of IdentityDbContext we're inheriting in the class declaration. This tells Identity which class in the application will contain the user account information it will be responsible for authenticating.

Configuring Program.cs

Finally, let's update our Program.cs file and configure the application to use Identity with Entity Framework and MVC.

Program.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using ToDoList.Models;
using Microsoft.AspNetCore.Identity;

namespace ToDoList
{
  class Program
  {
    static void Main(string[] args)
    {

      WebApplicationBuilder builder = WebApplication.CreateBuilder(args);

      builder.Services.AddControllersWithViews();

      builder.Services.AddDbContext<ToDoListContext>(
                        dbContextOptions => dbContextOptions
                          .UseMySql(
                            builder.Configuration["ConnectionStrings:DefaultConnection"], ServerVersion.AutoDetect(builder.Configuration["ConnectionStrings:DefaultConnection"]
                          )
                        )
                      );
      
      // New code below!!
      builder.Services.AddIdentity<ApplicationUser, IdentityRole>()
                .AddEntityFrameworkStores<ToDoListContext>()
                .AddDefaultTokenProviders();

      WebApplication app = builder.Build();

      // app.UseDeveloperExceptionPage();
      app.UseHttpsRedirection();
      app.UseStaticFiles();

      app.UseRouting();

      // New code below!
      app.UseAuthentication(); 
      app.UseAuthorization();

      app.MapControllerRoute(
          name: "default",
          pattern: "{controller=Home}/{action=Index}/{id?}"
        );

      app.Run();
    }
  }
}

• We add the using directive using Microsoft.AspNetCore.Identity; so our Program class has access to Identity.

• We set up Identity as a service with the line builder.Services.AddIdentity<ApplicationUser, IdentityRole>(). Notice that we specify <ApplicationUser, IdentityRole> — these are the two models that we're using to designate the user and the role. Just like IdentityUser, IdentityRole is a built-in class to Identity, and it allows us to use the default configurations for roles. We won't be configuring roles beyond the defaults, so we use the built-in IdentityRole class here.

• We chain two more method calls to the Identity service that we set up: .AddEntityFrameworkStores<ToDoListContext>() and .AddDefaultTokenProviders();. The first method ensures that the Identity user data is saved via EF Core to our database (as represented by the ToDoListContext class). The second method sets up Identity's providers for tokens, which are created during password reset or two factor authentication, for example. Note that we won't go over how to implement either of those two things in the coursework, and you are encouraged to look into them on your own.

• Finally, we configure our web application app to .UseAuthentication() and .UseAuthorization(). Remember two things here:

  • Whenever we call a method on our WebApplication app, we are configuring how our application handles HTTP requests (the "pipeline"). We configure the request pipeline by setting up middleware. Middleware is software that we add to our request pipeline that determines how the request should be processed. Each middleware decides whether to do some work, or to pass the request onto the next middleware. To optionally review more about this topic, visit the MS Docs.
  • The order in which we set up the middleware matters! If these methods are called in the wrong order, you may run into unhandled exceptions or issues logging in with Identity. Fortunately, the Microsoft Docs has a list of how middleware should be ordered.

Create a Migration and Update the Database

Now that the project is configured to use Identity, it's time to create a new migration and update our database. Run these two commands within the ToDoList/ project folder:

$ dotnet ef migrations add AddIdentity
$ dotnet ef database update

Repository Reference

Follow the link below to view how a sample version of the project should look at this point. Note that this is a link to a specific branch in the repository.

Example GitHub Repo for To Do List with Authentication and Authorization: 1_identity_setup