Adding ASP.NET MVC5 Identity Authentication to an existing project

Question

Configuring Identity to your existing project is not hard thing. You must install some NuGet package and do some small configuration.

First install these NuGet packages with Package Manager Console:

PM> Install-Package Microsoft.AspNet.Identity.Owin 
PM> Install-Package Microsoft.AspNet.Identity.EntityFramework
PM> Install-Package Microsoft.Owin.Host.SystemWeb 

Add a user class and with IdentityUser inheritance:

public class AppUser : IdentityUser
{
    //add your custom properties which have not included in IdentityUser before
    public string MyExtraProperty { get; set; }  
}

Do same thing for role:

public class AppRole : IdentityRole
{
    public AppRole() : base() { }
    public AppRole(string name) : base(name) { }
    // extra properties here 
}

Change your DbContext parent from DbContext to IdentityDbContext<AppUser> like this:

public class MyDbContext : IdentityDbContext<AppUser>
{
    // Other part of codes still same 
    // You don't need to add AppUser and AppRole 
    // since automatically added by inheriting form IdentityDbContext<AppUser>
}

If you use the same connection string and enabled migration, EF will create necessary tables for you.

Optionally, you could extend UserManager to add your desired configuration and customization:

public class AppUserManager : UserManager<AppUser>
{
    public AppUserManager(IUserStore<AppUser> store)
        : base(store)
    {
    }

    // this method is called by Owin therefore this is the best place to configure your User Manager
    public static AppUserManager Create(
        IdentityFactoryOptions<AppUserManager> options, IOwinContext context)
    {
        var manager = new AppUserManager(
            new UserStore<AppUser>(context.Get<MyDbContext>()));

        // optionally configure your manager
        // ...

        return manager;
    }
}

Since Identity is based on OWIN you need to configure OWIN too:

Add a class to App_Start folder (or anywhere else if you want). This class is used by OWIN. This will be your startup class.

namespace MyAppNamespace
{
    public class IdentityConfig
    {
        public void Configuration(IAppBuilder app)
        {
            app.CreatePerOwinContext(() => new MyDbContext());
            app.CreatePerOwinContext<AppUserManager>(AppUserManager.Create);
            app.CreatePerOwinContext<RoleManager<AppRole>>((options, context) =>
                new RoleManager<AppRole>(
                    new RoleStore<AppRole>(context.Get<MyDbContext>())));

            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/Home/Login"),
            });
        }
    }
}

Almost done just add this line of code to your web.config file so OWIN could find your startup class.

<appSettings>
    <!-- other setting here -->
    <add key="owin:AppStartup" value="MyAppNamespace.IdentityConfig" />
</appSettings>

Now in entire project you could use Identity just like any new project had already installed by VS. Consider login action for example

[HttpPost]
public ActionResult Login(LoginViewModel login)
{
    if (ModelState.IsValid)
    {
        var userManager = HttpContext.GetOwinContext().GetUserManager<AppUserManager>();
        var authManager = HttpContext.GetOwinContext().Authentication;

        AppUser user = userManager.Find(login.UserName, login.Password);
        if (user != null)
        {
            var ident = userManager.CreateIdentity(user, 
                DefaultAuthenticationTypes.ApplicationCookie);
            //use the instance that has been created. 
            authManager.SignIn(
                new AuthenticationProperties { IsPersistent = false }, ident);
            return Redirect(login.ReturnUrl ?? Url.Action("Index", "Home"));
        }
    }
    ModelState.AddModelError("", "Invalid username or password");
    return View(login);
}

You could make roles and add to your users:

public ActionResult CreateRole(string roleName)
{
    var roleManager=HttpContext.GetOwinContext().GetUserManager<RoleManager<AppRole>>();

    if (!roleManager.RoleExists(roleName))
        roleManager.Create(new AppRole(roleName));
    // rest of code
} 

You could also add a role to a user, like this:

UserManager.AddToRole(UserManager.FindByName("username").Id, "roleName");

By using Authorize you could guard your actions or controllers:

[Authorize]
public ActionResult MySecretAction() {}

or

[Authorize(Roles = "Admin")]]
public ActionResult MySecretAction() {}

You can also install additional packages and configure them to meet your requirement like Microsoft.Owin.Security.Facebook or whichever you want.

Note: Don't forget to add relevant namespaces to your files:

using Microsoft.AspNet.Identity;
using Microsoft.Owin.Security;
using Microsoft.AspNet.Identity.Owin;
using Microsoft.AspNet.Identity.EntityFramework;
using Microsoft.Owin;
using Microsoft.Owin.Security.Cookies;
using Owin;

You could also see my other answers like this and this for advanced use of Identity.

This is what I did to integrate Identity with an existing database.

1. Create a sample MVC project with MVC template. This has all the code needed for Identity implementation - Startup.Auth.cs, IdentityConfig.cs, Account Controller code, Manage Controller, Models and related views.

2. Install the necessary nuget packages for Identity and OWIN. You will get an idea by seeing the references in the sample Project and the answer by @Sam

3. Copy all these code to your existing project. Please note don't forget to add the "DefaultConnection" connection string for Identity to map to your database. Please check the ApplicationDBContext class in IdentityModel.cs where you will find the reference to "DefaultConnection" connection string.

4. This is the SQL script I ran on my existing database to create necessary tables:

   USE ["YourDatabse"]
   GO
   /****** Object:  Table [dbo].[AspNetRoles]    Script Date: 16-Aug-15 6:52:25 PM ******/
   SET ANSI_NULLS ON
   GO
   SET QUOTED_IDENTIFIER ON
   GO
   CREATE TABLE [dbo].[AspNetRoles](
   [Id] [nvarchar](128) NOT NULL,
   [Name] [nvarchar](256) NOT NULL,
   CONSTRAINT [PK_dbo.AspNetRoles] PRIMARY KEY CLUSTERED 
   (
     [Id] ASC
   )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
   ) ON [PRIMARY]
   
   GO
   /****** Object:  Table [dbo].[AspNetUserClaims]    Script Date: 16-Aug-15 6:52:25 PM ******/
   SET ANSI_NULLS ON
   GO
   SET QUOTED_IDENTIFIER ON
   GO
   CREATE TABLE [dbo].[AspNetUserClaims](
      [Id] [int] IDENTITY(1,1) NOT NULL,
      [UserId] [nvarchar](128) NOT NULL,
      [ClaimType] [nvarchar](max) NULL,
      [ClaimValue] [nvarchar](max) NULL,
   CONSTRAINT [PK_dbo.AspNetUserClaims] PRIMARY KEY CLUSTERED 
   (
      [Id] ASC
   )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
   ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
   
   GO
   /****** Object:  Table [dbo].[AspNetUserLogins]    Script Date: 16-Aug-15 6:52:25 PM ******/
   SET ANSI_NULLS ON
   GO
   SET QUOTED_IDENTIFIER ON
   GO
   CREATE TABLE [dbo].[AspNetUserLogins](
       [LoginProvider] [nvarchar](128) NOT NULL,
       [ProviderKey] [nvarchar](128) NOT NULL,
       [UserId] [nvarchar](128) NOT NULL,
   CONSTRAINT [PK_dbo.AspNetUserLogins] PRIMARY KEY CLUSTERED 
   (
       [LoginProvider] ASC,
       [ProviderKey] ASC,
       [UserId] ASC
   )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
   ) ON [PRIMARY]
   
   GO
   /****** Object:  Table [dbo].[AspNetUserRoles]    Script Date: 16-Aug-15 6:52:25 PM ******/
   SET ANSI_NULLS ON
   GO
   SET QUOTED_IDENTIFIER ON
   GO
   CREATE TABLE [dbo].[AspNetUserRoles](
      [UserId] [nvarchar](128) NOT NULL,
      [RoleId] [nvarchar](128) NOT NULL,
   CONSTRAINT [PK_dbo.AspNetUserRoles] PRIMARY KEY CLUSTERED 
   (
       [UserId] ASC,
       [RoleId] ASC
   )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
   ) ON [PRIMARY]
   
   GO
   /****** Object:  Table [dbo].[AspNetUsers]    Script Date: 16-Aug-15 6:52:25 PM ******/
   SET ANSI_NULLS ON
   GO
   SET QUOTED_IDENTIFIER ON
   GO
   CREATE TABLE [dbo].[AspNetUsers](
       [Id] [nvarchar](128) NOT NULL,
       [Email] [nvarchar](256) NULL,
       [EmailConfirmed] [bit] NOT NULL,
       [PasswordHash] [nvarchar](max) NULL,
       [SecurityStamp] [nvarchar](max) NULL,
       [PhoneNumber] [nvarchar](max) NULL,
       [PhoneNumberConfirmed] [bit] NOT NULL,
       [TwoFactorEnabled] [bit] NOT NULL,
       [LockoutEndDateUtc] [datetime] NULL,
       [LockoutEnabled] [bit] NOT NULL,
       [AccessFailedCount] [int] NOT NULL,
       [UserName] [nvarchar](256) NOT NULL,
   CONSTRAINT [PK_dbo.AspNetUsers] PRIMARY KEY CLUSTERED 
   (
       [Id] ASC
   )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
   ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
   
    GO
    ALTER TABLE [dbo].[AspNetUserClaims]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])
    REFERENCES [dbo].[AspNetUsers] ([Id])
    ON DELETE CASCADE
    GO
    ALTER TABLE [dbo].[AspNetUserClaims] CHECK CONSTRAINT [FK_dbo.AspNetUserClaims_dbo.AspNetUsers_UserId]
    GO
    ALTER TABLE [dbo].[AspNetUserLogins]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])
    REFERENCES [dbo].[AspNetUsers] ([Id])
    ON DELETE CASCADE
    GO
    ALTER TABLE [dbo].[AspNetUserLogins] CHECK CONSTRAINT [FK_dbo.AspNetUserLogins_dbo.AspNetUsers_UserId]
    GO
    ALTER TABLE [dbo].[AspNetUserRoles]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId] FOREIGN KEY([RoleId])
    REFERENCES [dbo].[AspNetRoles] ([Id])
    ON DELETE CASCADE
    GO
    ALTER TABLE [dbo].[AspNetUserRoles] CHECK CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetRoles_RoleId]
    GO
    ALTER TABLE [dbo].[AspNetUserRoles]  WITH CHECK ADD  CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId] FOREIGN KEY([UserId])
    REFERENCES [dbo].[AspNetUsers] ([Id])
    ON DELETE CASCADE
    GO
    ALTER TABLE [dbo].[AspNetUserRoles] CHECK CONSTRAINT [FK_dbo.AspNetUserRoles_dbo.AspNetUsers_UserId]
    GO
   

5. Check and solve any remaining errors and you are done. Identity will handle the rest :)

I recommend IdentityServer.This is a .NET Foundation project and covers many issues about authentication and authorization.

Overview

IdentityServer is a .NET/Katana-based framework and hostable component that allows implementing single sign-on and access control for modern web applications and APIs using protocols like OpenID Connect and OAuth2. It supports a wide range of clients like mobile, web, SPAs and desktop applications and is extensible to allow integration in new and existing architectures.

For more information, e.g.

• support for MembershipReboot and ASP.NET Identity based user stores
• support for additional Katana authentication middleware (e.g. Google, Twitter, Facebook etc)
• support for EntityFramework based persistence of configuration
• support for WS-Federation
• extensibility

check out the documentation and the demo.