AspNetCoreIdentity.MongoDriver

A provisioner for AspNetCore Identity using MongoDB as the backing store.

Features

This implements all of the interfaces required by the AspNetCore Identity system.

It also includes a UserStore and RoleStore implementation that can be used with the UserManager and RoleManager classes.

A typical connection string for local development would be mongodb://localhost:27017/Identity.

This would create a database called Identity and store the collections in there.

Usage

Register the provider in Program.cs:

builder.Services.AddIdentityMongoDbProvider<MongoUser<Guid>, MongoRole<Guid>, Guid>(identity =>
{
    identity.User.RequireUniqueEmail = true;
}, mongo =>
{
    mongo.ConnectionString = builder.Configuration.GetConnectionString("MongoDb")!;
});

Then take UserManager<MongoUser<Guid>> and RoleManager<MongoRole<Guid>> as constructor or handler parameters wherever you need them; they are registered as scoped services and the container manages their lifetime. Do not call BuildServiceProvider() yourself or cache the managers in long-lived objects.

public class AccountController(UserManager<MongoUser<Guid>> userManager) : Controller
{
    // ...
}

Note

The MongoUser and MongoRole classes are provided by the library and are generic. This allows you to use any type for the key, not just a Guid.

If you want to use a Guid as the key, you need to insert the line BsonSerializer.RegisterSerializer(new GuidSerializer(GuidRepresentation.Standard)); somewhere above this.

If you use string keys and do not assign an Id yourself, the store generates an ObjectId-style string on create.

Initialization, indexes, and migrations

On the first store operation (not during service registration) the library:

• applies any pending schema migrations, guarded by a distributed lock so multiple application instances starting at once apply them exactly once, and
• creates its indexes: a unique index on NormalizedUserName, an index on NormalizedEmail, a compound index on Logins.LoginProvider/Logins.ProviderKey, and a unique index on the role NormalizedName.

Because the unique index on NormalizedUserName enforces real uniqueness, index creation will fail if existing data already contains duplicate user names — clean those up before upgrading. Set mongo.DisableIndexCreation = true if you manage indexes yourself, and mongo.DisableAutoMigrations = true if you manage schema upgrades yourself. You can also warm up eagerly at startup by resolving MongoIdentityInitializer from the container and awaiting EnsureInitializedAsync().

Concurrency

Updates and deletes use optimistic concurrency via the Identity ConcurrencyStamp. If the document changed since your copy was loaded, the operation fails with a ConcurrencyFailure error instead of silently overwriting the other write — reload the user/role and retry.

Limitations

options.Stores.ProtectPersonalData is not supported: the store does not encrypt personal data at rest, and enabling that option will throw at runtime by design rather than silently storing data unprotected.