How to access users when Identity project uses EF Core and Class Library uses EF6 with same database - asp.net

Question

We have a .NET Core project that uses Identity 3 and IdentityDbContext using EF Core for user management. The generated tables are stored in a common SQL server database that is also being used by another project in our solution that is a .NET 4.5.2 Framework DataLayer using EF6.
(Just some more background - the .NET Core project is an authorization server that uses OpenIddict to implement OpenIdConnect and Oauth2 and is configured with Identity so that we can save users to the database and login and authenticate)
Once we've authenticated, we make calls to our API end point. The API talks to a DataLayer that works with EF6. From this project I need to fetch the logged in user and work with users for various queries. Ideally, I wanted to use and extend the same AspNetUsers table.
I am wondering what the recommended approach is here? If I try to generate a User DbContext in the EF6 project I have to add a new migration and the scaffolding wants to create a new table - one that already exists in the database. I am a little unsure about having 2 separate contexts in 2 different projects and how these can "play nice" together.

Answer 1

I have handled similar scenario recently. I followed this approach.
I have a separate Class Library for Data Layer, which has Identity related Repositories/Stores, migrations and DbContext. The DbContext takes connection string from the host project.
.Net Core project has connection string specified in appSettings.json. This connection string points to same database. This project implements IdentityServer3 and acts as Token Service.
.Net 4.5.2 project has connection string specified in web.config . This also points to same database. This app gets token from .net core project and uses that Bearer Token to access other APIs.
I created another project to keep the Entities and this project is referenced in both .net core and .net hosts.
This way i have one common data layer for 2 host projects and 2 different service/business layers for 2 host projects. It is working nicely for me.
As EF 7.0 doesn't support seeding, I have a console app for seeding data into database. Even this console app accesses the same database through Data Layer.
So 3 different projects are accessing same database.
I can't share my code with public. I hope this helps.

Answer 2

I was able to get this to work. The main issue is that I just wanted to access my AspNetUsers table that was generated by Identity 3 in the DotNet Core project in my DotNet 4.51 DataLayer class library project.
I achieved this by creating a User.cs Entity class in the class library EF 6 project and making sure it's properties matched the columns from the Identity 3 generated ApplicationUser.cs class.
User.cs
public class User{
[Key]
public string Id { get; set; }
public int AccessFailedCount { get; set; }
public string ConcurrencyStamp { get; set; }
public string Email { get; set; }
public bool EmailConfirmed { get; set; }
public bool LockoutEnabled { get; set; }
public DateTimeOffset? LockoutEnd { get; set; }
public string NormalizedEmail { get; set; }
public string NormalizedUserName { get; set; }
public virtual string PasswordHash { get; set; }
public string PhoneNumber { get; set; }
public bool PhoneNumberConfirmed { get; set; }
public virtual string SecurityStamp { get; set; }
public bool TwoFactorEnabled { get; set; }
public string UserName { get; set; }
}
I then set up an EntityConfiguration to map to the AspNetUsers table
UserConfiguration.cs
public class UserConfiguration : EntityTypeConfiguration<User>
{
public UserConfiguration()
{
ToTable("AspNetUsers");
}
}
In my DbContext class I added a DbSet for my Users entity:
public virtual IDbSet<User> Users { get; set; }
I then ran the Add-Migration command to scaffold the changes. Once generated, I commented out the code and applied the migration to the database. This generates a row in the __MigrationsHistory table for the AspNetUsers table but doesn't try to recreate the table.
I was then able to successfully talk to the AspNetUsers table from the DataLayer EF6 project :)
Also it seems that I can also extend the AspNetUsers table with custom columns now by adding properties to my User.cs class and doing the migrations in the EF6 Datalayer project.