Integrating security into your application is a crucial step. So that only authenticated users are permitted access to the application. ASP.NET Core Identity is a robust system that facilitates the authentication of users in ASP.NET Core applications. User registration, login, password administration, role-based authorization, and integration with external authentication providers are among its many features.

You will learn how to add identity service to your ASP.NET 6 MVC project in this article. Before beginning, let's examine the fundamentals.

What is ASP.NET MVC Core?
Microsoft ASP.NET Core MVC is a robust and adaptable web application development framework for the ASP.NET Core platform. The model, the view, and the controller are the three distinct application components that are separated by MVC. The model represents the data and business logic of the application. It contains the necessary data structures, logic, and algorithms for manipulating and processing the data. The view is accountable for displaying the user interface to the end user. The view receives data from the model and displays it in an approachable manner. The controller mediates between the model and view. The controller manages the application's flow by receiving and processing requests and returning the appropriate response.

What is the difference between authentication and authorization?
Authentication and authorization are essential application development components. Authentication is the process of confirming a user's identity, assuring that they are who they claim to be. Authorization, on the other hand, is the process of granting or denying access to specific resources or functionalities based on the permissions and roles of the authenticated user.

It is essential to employ a secure authentication and authorization mechanism in today's digital environment, where sensitive user data and confidential information are involved. It protects user accounts, restricts unauthorised access to sensitive data, and ensures that only authorised users are able to perform specific actions within the application. By effectively incorporating authentication and authorization, developers can increase the overall security and credibility of web applications.

What is ASP.NET Identity Core?
ASP.NET Core Identity is a membership system for ASP.NET Core applications that provides support for user authentication and authorization. It simplifies the management of user accounts, passwords, and roles, allowing developers to concentrate on the essential functionality of applications.

In other words, ASP.NET provides the necessary functionality for adding features such as registering, logging in, logging out, managing users, passwords, profiles, authorization, roles, claims, tokens, and email confirmation.

ASP.NET Core Identity provides a comprehensive set of features, including user registration, login, password management, role-based authorization, and integration with external authentication providers. It integrates seamlessly with ASP.NET Core MVC, making it simple to add authentication and authorization features to your web application.

Using ASP.NET Core Identity, developers can employ secure authentication mechanisms, such as cookies and JSON Web Tokens (JWT). In addition, it features a flexible and extensible architecture that permits customization and integration with existing user repositories and providers. Whether you are developing a small-scale application or a large enterprise-level system, ASP.NET Core Identity provides the tools and APIs required to implement secure and scalable authentication and authorization solutions.

How Do I Configure ASP.NET Core Identity In My Project?
To perform authentication using Identity, I will create a brand-new project. Let us now establish the project.

1. Establishing the undertaking
Open Visual Studio 2022. Select "Create a new project" and then select "Next". Click "Next" after selecting the "ASP.NET Core Web App (Model-View-Controller)" template.

Click "Next" after customising the project and solution names and selecting the location where you desire to save the project. The name of our initiative is CRMApp.

Click "Create" after selecting "NET 6" as the framework.

Now, the project has been effectively created.

Step 2: Configuring the database
Launch SSMS (SQL Server Management Server) and use it to create and manage databases.

create database SalesCRM;
use SalesCRM;

Step 3. Open appsetting.js and set the connection string.
"ConnectionStrings":
{
  "SalesCRMcnn": "Server=***;Database=SalesCRM;User Id=**;Password=****;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"
}

Step 4. Creating Models
Click on Models and add a new class named SalesleadEntity.cs. In this class, add the required properties for the model as shown below.
namespace CRMApp.Models
{
    public class SalesLeadEntity
    {
        public int Id { get; set; }
        public string? FirstName { get; set; }
        public string? LastName { get; set; }
        public string? Mobile { get; set; }
        public string? Email { get; set; }
        public string? Source { get; set; }
    }
}

Step 5. Adding Required Packages
Now, Right click on the project and select "Manage NuGet Packages". In the browse section, search the following packages and install them.
    Microsoft.EntityFrameworkCore
    Microsoft.EntityFrameworkCore.SqlServer
    Microsoft.EntityFrameworkCore.Tools
    Microsoft.AspNetCore.Identity.EntityFrameworkCore

Now, Create a new folder named "Data" in the project and add a new class named "ApplicationDbContext.cs".
using CRMApp.Models;
using Microsoft.EntityFrameworkCore;
namespace CRMApp.Data
{
    public class ApplicationDbContext : DbContext
    {
        public ApplicationDbContext(DbContextOptions options) : base(options)
        {
        }
        public DbSet<SalesLeadEntity> SalesLead { get; set; }
    }
}

Now, open program.cs, and add the following service in the file.
builder.Services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(builder.Configuration.GetConnectionString("SalesCRMcnn")));

Step 6. Adding the migration to the database
To add migration to the database, Go to "Tools" -> "NuGet Package Manager" -> "Package Manager Console", and the package manager console will open.

In the console, run the following commands.
add-migration "Initial migration"
Update-database

After running the above commands, a migration file will be added to your project, having folder name Migrations, and the database will be updated.

Step 7. Adding Controller
Click on Controller and add a new Scaffolded Item and select "MVC Controller with views, using Entity Framework," and click on "Add". A popup will open like this.

Choose "SalesLeadEntity" as the model class and "ApplicationDbContext" as DbContext class. Also, name the controller "LeadsController". Click on "Add", and a new controller will get created with action methods in it.

Now, go to "_Layout.cshtml" and add the following lines to make a new menu for the Sales Lead.
<li class="nav-item">
    <a class="nav-link text-dark" asp-area="" asp-controller="Leads" asp-action="Index">Sales Lead</a>
</li>

Now, if you will run the project and open the index page, you will have an empty page like this.

Here, click "Create New" to create a new record.

Once you add the records on the index page, you will have that records.

Step 8. Securing the project using Identity

Before adding Identity to the project, update the "ApplicationDbContext.cs" with the below code, as now we will be inheriting IdentityDbContext instead of DbContext.
using CRMApp.Models;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
namespace CRMApp.Data
{
    public class ApplicationDbContext : IdentityDbContext
    {
        ...
    }
}

Now, Right Click on the project and click on "Add new Scaffolded Item". Click on "Identity" and then click "Add".

Here, I have selected all options, but you can select according to your need and project requirements. Choose DbContextClass as "ApplicationDbContext" and Click on "Add".
Now, you will have Identity added to your project using scaffolding. Now, you will see a folder named Areas which has a sub-folder named Identity which contains a sub-folder names Account which has endpoints for login register, logout, etc in the form of razor pages.

Step 9.  Adding necessary code and updating the database
Open "_Layout.cs", and add the following code in the <nav> section before the </nav>
<partial name="_LoginPartial"/>

Now, you should be able to see Login and Register options in the right-side menu when running the project.

Add the following line in the Program.cs.
app.MapRazorPages();

Now, you will have to add migration to the database; go to "Tools", click on "NuGet Package Manager" and then on "Package Manager Console", the package manager console will open.

In the console, run the following commands.
add-migration "Identity tables migration"
Update-database

Here, a new migration file will be added to the Migration folder, and necessary tables are added to the database.

Step 10. Create a new account
Run the project and click on register to register users. A Register page will open like the one below.

Here, you can register users by filling in the fields given.

But, if you click on Sales Lead, you will see you can still access the sales lead page without logging. So, to prevent this, follow the next step.

Step 11. Adding security
Go to "LeadsController.cs"  and add attribute [Authorize] at the controller level.
namespace CRMApp.Controllers
{
    [Authorize]
    public class LeadsController : Controller
    {
       ...
    }
}

Now, if you will open the application and click on Sales Lead, you will see that you cannot access the page without logging in yourself. A page for login will open for you, as shown below.

Once you log in yourself using the email and password. You will be able to access the Index page with Sales Lead Details. Also, you will have options to edit, get details and delete the records.

Here, you can see the details.

As you have seen, we have successfully added authentication to our ASP. NET 6 projects using the Identity Service.

Conclusion
ASP.NET Core Identity is a powerful tool for implementing user authentication and authorization in ASP.NET Core applications. By leveraging its features, developers can easily incorporate secure and scalable authentication mechanisms into their web applications, enhancing overall security and user trust. ASP.NET Core Identity simplifies the process of managing user accounts, passwords, and roles, allowing developers to focus on the core functionality of their applications. With its seamless integration with ASP.NET Core MVC, developers can create robust user management functionality and ensure that only authorized users can access specific resources or functionalities within the application.

By following the steps outlined in this article, developers can successfully set up ASP.NET Core Identity in their projects and enjoy the benefits of a secure and efficient authentication system.

ASP.NET Core MVC is a framework used to develop web applications, also used for building modern and dynamic web applications. It is developed to run on multiple environments like Windows, Linux, and macOS. These operating systems provide a rich set of features that make it easy to build and deploy web applications. Some of the key features of ASP.NET Core MVC include dependency injection, routing, model binding, validation, and Razor views for building UI. It also provides support for building RESTful APIs, where developers can create scalable and flexible web applications.

The main problem arises when we want to redirect to the page which we want to occur when we perform any specific event or action like submitting the form or login into the application but by default, it reloads and shows the same page again, and if we want to redirect into the desired page where it is showing the actual updated record, then we can use redirectToAction("page name")method.

How to use the redirectToAction() method?
The redirectToAction() method is used in frameworks like ASP.NET and ASP.NET Core. This method is used to redirect from one web page to the desired page. The RedirectToAction() method is part of the Controller class, which is used to handle incoming HTTP requests. The method takes one or more parameters to specify the action and controller to redirect to.

Here's an example to demonstrate the usage of the RedirectToAction() method in ASP.NET MVC.

Let's say you have a controller named HomeController with two action methods: Index() and About(). The Index() action method displays the home page, and the About() action method displays information about the website.
using System.Web.Mvc;

public class HomeController : Controller
{
    public ActionResult Index()
    {
        return View();
    }
    public ActionResult About()
    {
        return View();
    }
}

Let's assume that you want to redirect the user from the Index() action method to the About() action method when a certain condition is met. You can achieve this using the RedirectToAction() method.
public class HomeController : Controller
{
    public ActionResult Index()
    {
        if (/* check condition */) // Replace this with your condition
        {
            return RedirectToAction("About");
        }
        return View();
    }
    public ActionResult About()
    {
        return View();
    }
}

In the example above, if the condition inside the Index() action method evaluates to true, the RedirectToAction() method is called with the parameter "About". This redirects the user to the About() action method, and the associated view is rendered.

The RedirectToAction()  method can also accept additional parameters to pass data between actions. For example

return RedirectToAction("About", new { id = 123 });

In this case, the About() action method can receive the id parameter to perform further processing.

The RedirectToAction() method in ASP.NET is used to redirect users from one action method to another within the same or different controller. It is commonly used in MVC applications for navigation and routing purposes. Using this method, you can control the flow of your application and redirect users based on specific conditions or events.
FAQ'S

Q1. What's the difference between RedirectToAction() and Redirect() methods?
A. The RedirectToAction() method is used to redirect users to another action method within the application, while the Redirect() method is used to redirect users to a different URL or external website.

Q2. Can I redirect to an action method in a different controller?
A. Yes, you can use the RedirectToAction() method to redirect to an action method in a different controller by specifying the controller name as a parameter.

Q3. Is it possible to redirect to an external URL using RedirectToAction()
A. No, the RedirectToAction() method is specifically designed for redirecting within the application. If you need to redirect to an external URL, you should use the Redirect() method and provide the URL as a parameter.