AspNetCoreMultiTenantIdentity

(Or ASP.NET Core Multi-Tenant Identity)

Long name for a simple purpose: add multi-tenant support to ASP.NET Core Identity.

Requirements

This project is built on .NET Standard 2.0. It currently works with ASP.NET Core Identity version 2.1.

The Basics

Installation

To get the basics, install the core package from NuGet:

Install-Package Eleven41.AspNetCore.MultiTenantIdentity

Setup

1. Add using directives where required:

using Eleven41.AspNetCore.MultiTenantIdentity;

2. Derive your user class from MultiTenantUser rather than IdentityUser:

class ApplicationUser : MultiTenantUser
{
}

You can also derive from MultiTenantUser<> to indicate the key type.

The MultiTenantUser class adds a TenantId member to your users to indicate the tenant they are a member of. This new property is required. So it must be set on your user before the user is added to your store.

Please see the samples for a registration example.

3. If you are also using roles, derive your role class from MultiTenantRole rather than IdentityRole:

class ApplicationRole : MultiTenantRole
{
}

Similarly, you can template the MultiTenantRole<> with the key type.

4. This package introduces a new class called IdentityTenant that represents the tenants (groups, organizations, companies) that your users are contained within. This class can be templated using IdentityTenant<> to indicate the key type.

Note: Key types should be the same between users, roles, and tenants.

5. In Startup.cs, install the core services after your

services.AddDefaultIdentity<ApplicationUser>()
    .AddMultiTenantIdentity<ApplicationTenant>()
    ;

This will add TenantManager<ApplicationUser, ApplicationTenant> into the dependency injection services.

Usage

In your controllers, access the tenant manager as follows:

class HomeController
{
    TenantManager<ApplicationUser, ApplicationTenant> _tenantManager;

    public HomeController(TenantManager<ApplicationUser, ApplicationTenant> tenantManager)
    {
        _tenantManager = tenantManager ?? throw new ArgumentNullException(nameof(tenantManager));
    }

    public async Task<IActionResult> Index()
    {
        if (this.User.Identity.IsAuthenticated)
        {
            var user = await _userManager.GetUserAsync(this.User);
            var tenant = await _tenantManager.FindByIdAsync(user.TenantId.ToString());
            ViewData["TenantName"] = await _tenantManager.GetNameAsync(tenant);
        }
        return View();
    }
}

Entity Framework Core Usage

Installation

If you are using Entity Framework Core for your identity storage, you should also install the Entity Framework middleware:

Install-Package Eleven41.AspNetCore.MultiTenantIdentity.EntityFrameworkCore

Setup

1. Add using directives where required:

using Eleven41.AspNetCore.MultiTenantIdentity.EntityFrameworkCore;

2. Derive your Identity context from MultiTenantIdentityDbContext (if you are using roles) or MultiTenantIdentityUserContext if you are not using roles. Basically, just put MultiTenant at the start of the base class you're using.

public class ApplicationIdentityContext : MultiTenantIdentityUserContext<ApplicationUser, ApplicationTenant> 
{
    public ApplicationIdentityContext(DbContextOptions<ApplicationIdentityContext> options)
            : base(options)
    {
    }
}

3. In Startup.cs, call AddMultiTenantEntityFrameworkStores with your identity context class.

services.AddDefaultIdentity<ApplicationUser>()
    .AddEntityFrameworkStores<IdentityContext>()

    .AddMultiTenantIdentity<ApplicationTenant>()
    .AddMultiTenantEntityFrameworkStores<ApplicationIdentityContext>()
    ;

4. Add a database migration.

   dotnet ef migrations add AddMultiTenancy

5. Update your database.

   dotnet ef database update

At this point, you should see 2 things in your database:

• A new table was added called AspNetTenants.
• The AspNetUsers table should have a new column called TenantId with a foreign key pointing to AspNetTenants.

Current Functionality

• User names and emails must still follow the normal Identity uniqueness requirements. Users are not isolated within tenants.
• Adding multi-tenancy to an existing database is currently problematic since the TenantId added to users is non-null and required.

Goals

• Add user management pages to add to your MVC applications to add/remove users within a tenant.
• Add optional user isolation to allow the same username and email in multiple tenants.