Account confirmation and password recovery in ASP.NET Core

By Rick Anderson and Joe Audette

This tutorial shows you how to build an ASP.NET Core app with email confirmation and password reset. This tutorial is not a beginning topic. You should be familiar with:

See this PDF file for the ASP.NET Core MVC 1.1 and 2.x versions.

Prerequisites

.NET Core 2.1.4 SDK or later.

Create a new ASP.NET Core project with the .NET Core CLI

dotnet new razor --auth Individual -o WebPWrecover
cd WebPWrecover
  • --auth Individual specifies the Individual User Accounts project template.
  • On Windows, add the -uld option. It specifies LocalDB should be used instead of SQLite.
  • Run new mvc --help to get help on this command.

Alternatively, you can create a new ASP.NET Core project with Visual Studio:

  • In Visual Studio, create a new Web Application project.
  • Select ASP.NET Core 2.0. .NET Core is selected in the following image, but you can select .NET Framework.
  • Select Change Authentication and set to Individual User Accounts.
  • Keep the default Store user accounts in-app.

New Project dialog showing "Individual User Accounts radio" selected

Test new user registration

Run the app, select the Register link, and register a user. Follow the instructions to run Entity Framework Core migrations. At this point, the only validation on the email is with the [EmailAddress] attribute. After submitting the registration, you are logged into the app. Later in the tutorial, the code is updated so new users can't log in until their email has been validated.

View the Identity database

See Working with SQLite in an ASP.NET Core MVC project for instructions on how to view the SQLite database.

For Visual Studio:

  • From the View menu, select SQL Server Object Explorer (SSOX).
  • Navigate to (localdb)MSSQLLocalDB(SQL Server 13). Right-click on dbo.AspNetUsers > View Data:

Contextual menu on AspNetUsers table in SQL Server Object Explorer

Note the table's EmailConfirmed field is False.

You might want to use this email again in the next step when the app sends a confirmation email. Right-click on the row and select Delete. Deleting the email alias makes it easier in the following steps.


Require HTTPS

See Require HTTPS.

Require email confirmation

It's a best practice to confirm the email of a new user registration. Email confirmation helps to verify they're not impersonating someone else (that is, they haven't registered with someone else's email). Suppose you had a discussion forum, and you wanted to prevent "yli@example.com" from registering as "nolivetto@contoso.com." Without email confirmation, "nolivetto@contoso.com" could receive unwanted email from your app. Suppose the user accidentally registered as "ylo@example.com" and hadn't noticed the misspelling of "yli". They wouldn't be able to use password recovery because the app doesn't have their correct email. Email confirmation provides only limited protection from bots. Email confirmation doesn't provide protection from malicious users with many email accounts.

You generally want to prevent new users from posting any data to your web site before they have a confirmed email.

Update ConfigureServices to require a confirmed email:

public void ConfigureServices(IServiceCollection services)
{
    // Requires using Microsoft.AspNetCore.Mvc;
    services.Configure<MvcOptions>(options =>
    {
        options.Filters.Add(new RequireHttpsAttribute());
    });

    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    services.AddIdentity<ApplicationUser, IdentityRole>(config =>
    {
        config.SignIn.RequireConfirmedEmail = true;
    })
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

    services.AddMvc()
        .AddRazorPagesOptions(options =>
        {
            options.Conventions.AuthorizeFolder("/Account/Manage");
            options.Conventions.AuthorizePage("/Account/Logout");
        });

config.SignIn.RequireConfirmedEmail = true; prevents registered users from logging in until their email is confirmed.

Configure email provider

In this tutorial, SendGrid is used to send email. You need a SendGrid account and key to send email. You can use other email providers. ASP.NET Core 2.x includes System.Net.Mail, which allows you to send email from your app. We recommend you use SendGrid or another email service to send email. SMTP is difficult to secure and set up correctly.

The Options pattern is used to access the user account and key settings. For more information, see configuration.

Create a class to fetch the secure email key. For this sample, the AuthMessageSenderOptions class is created in the Services/AuthMessageSenderOptions.cs file:

public class AuthMessageSenderOptions
{
        public string SendGridUser { get; set; }
        public string SendGridKey { get; set; }
}

Set the SendGridUser and SendGridKey with the secret-manager tool. For example:

C:\WebAppl\src\WebApp1>dotnet user-secrets set SendGridUser RickAndMSFT
info: Successfully saved SendGridUser = RickAndMSFT to the secret store.

On Windows, Secret Manager stores keys/value pairs in a secrets.json file in the %APPDATA%/Microsoft/UserSecrets/<WebAppName-userSecretsId> directory.

The contents of the secrets.json file aren't encrypted. The secrets.json file is shown below (the SendGridKey value has been removed.)

 {
   "SendGridUser": "RickAndMSFT",
   "SendGridKey": "<key removed>"
 }

Configure startup to use AuthMessageSenderOptions

Add AuthMessageSenderOptions to the service container at the end of the ConfigureServices method in the Startup.cs file:

public void ConfigureServices(IServiceCollection services)
{
    // Requires using Microsoft.AspNetCore.Mvc;
    services.Configure<MvcOptions>(options =>
    {
        options.Filters.Add(new RequireHttpsAttribute());
    });

    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    services.AddIdentity<ApplicationUser, IdentityRole>(config =>
    {
        config.SignIn.RequireConfirmedEmail = true;
    })
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

    services.AddMvc()
        .AddRazorPagesOptions(options =>
        {
            options.Conventions.AuthorizeFolder("/Account/Manage");
            options.Conventions.AuthorizePage("/Account/Logout");
        });

    services.AddSingleton<IEmailSender, EmailSender>();

    services.Configure<AuthMessageSenderOptions>(Configuration);
}

Configure the AuthMessageSender class

This tutorial shows how to add email notifications through SendGrid, but you can send email using SMTP and other mechanisms.

Install the SendGrid NuGet package:

  • From the command line:

    dotnet add package SendGrid

  • From the Package Manager Console, enter the following command:

    Install-Package SendGrid

See Get Started with SendGrid for Free to register for a free SendGrid account.

Configure SendGrid

To configure SendGrid, add code similar to the following in Services/EmailSender.cs:

using Microsoft.Extensions.Options;
using SendGrid;
using SendGrid.Helpers.Mail;
using System.Threading.Tasks;

namespace WebPWrecover.Services
{
    public class EmailSender : IEmailSender
    {
        public EmailSender(IOptions<AuthMessageSenderOptions> optionsAccessor)
        {
            Options = optionsAccessor.Value;
        }

        public AuthMessageSenderOptions Options { get; } //set only via Secret Manager

        public Task SendEmailAsync(string email, string subject, string message)
        {
            return Execute(Options.SendGridKey, subject, message, email);
        }

        public Task Execute(string apiKey, string subject, string message, string email)
        {
            var client = new SendGridClient(apiKey);
            var msg = new SendGridMessage()
            {
                From = new EmailAddress("Joe@contoso.com", "Joe Smith"),
                Subject = subject,
                PlainTextContent = message,
                HtmlContent = message
            };
            msg.AddTo(new EmailAddress(email));
            return client.SendEmailAsync(msg);
        }
    }
}

Enable account confirmation and password recovery

The template has the code for account confirmation and password recovery. Find the OnPostAsync method in Pages/Account/Register.cshtml.cs.

Prevent newly registered users from being automatically logged on by commenting out the following line:

await _signInManager.SignInAsync(user, isPersistent: false);

The complete method is shown with the changed line highlighted:

public async Task<IActionResult> OnPostAsync(string returnUrl = null)
{
    ReturnUrl = returnUrl;
    if (ModelState.IsValid)
    {
        var user = new ApplicationUser { UserName = Input.Email, Email = Input.Email };
        var result = await _userManager.CreateAsync(user, Input.Password);
        if (result.Succeeded)
        {
            _logger.LogInformation("User created a new account with password.");

            var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
            var callbackUrl = Url.EmailConfirmationLink(user.Id, code, Request.Scheme);
            await _emailSender.SendEmailConfirmationAsync(Input.Email, callbackUrl);

            // await _signInManager.SignInAsync(user, isPersistent: false);
            return LocalRedirect(Url.GetLocalUrl(returnUrl));
        }
        foreach (var error in result.Errors)
        {
            ModelState.AddModelError(string.Empty, error.Description);
        }
    }

    // If we got this far, something failed, redisplay form
    return Page();
}

Register, confirm email, and reset password

Run the web app, and test the account confirmation and password recovery flow.

  • Run the app and register a new user

    Web application Account Register view

  • Check your email for the account confirmation link. See Debug email if you don't get the email.

  • Click the link to confirm your email.
  • Log in with your email and password.
  • Log off.

View the manage page

Select your user name in the browser: browser window with user name

You might need to expand the navbar to see user name.

navbar

The manage page is displayed with the Profile tab selected. The Email shows a check box indicating the email has been confirmed.

manage page

Test password reset

  • If you're logged in, select Logout.
  • Select the Log in link and select the Forgot your password? link.
  • Enter the email you used to register the account.
  • An email with a link to reset your password is sent. Check your email and click the link to reset your password. After your password has been successfully reset, you can log in with your email and new password.

Debug email

If you can't get email working:

  • Create a console app to send email.
  • Review the Email Activity page.
  • Check your spam folder.
  • Try another email alias on a different email provider (Microsoft, Yahoo, Gmail, etc.)
  • Try sending to different email accounts.

A security best practice is to not use production secrets in test and development. If you publish the app to Azure, you can set the SendGrid secrets as application settings in the Azure Web App portal. The configuration system is set up to read keys from environment variables.

Combine social and local login accounts

To complete this section, you must first enable an external authentication provider. See Enabling authentication using Facebook, Google, and other external providers.

You can combine local and social accounts by clicking on your email link. In the following sequence, "RickAndMSFT@gmail.com" is first created as a local login; however, you can create the account as a social login first, then add a local login.

Web application: RickAndMSFT@gmail.com user authenticated

Click on the Manage link. Note the 0 external (social logins) associated with this account.

Manage view

Click the link to another login service and accept the app requests. In the following image, Facebook is the external authentication provider:

Manage your external logins view listing Facebook

The two accounts have been combined. You are able to log on with either account. You might want your users to add local accounts in case their social login authentication service is down, or more likely they've lost access to their social account.

Enable account confirmation after a site has users

Enabling account confirmation on a site with users locks out all the existing users. Existing users are locked out because their accounts aren't confirmed. To work around exiting user lockout, use one of the following approaches:

  • Update the database to mark all existing users as being confirmed
  • Confirm exiting users. For example, batch-send emails with confirmation links.