ApplicationDbContext - where it belongs in project [closed]

Question

I want to use one (EF) context file in my mvc 5 app and I want to use asp identity.

I have a few projects in solution DAL, GUI and WebAPI.

I want to just move ApplicationDbContext in DAL assembly and remove EF completly from my UI project.

What you do with ApplicationDbContext and asp identity when you start your new projects?

Do you leave it in UI layer or you moving it to data layer?

I really don't have any experienced dev to ask I hope it will not be downvoted.

Answer 1

I presume you're talking about Entity Framework's DbContext? If so then you're right to keep this in your DAL assembly.

Moving it and changing your namespace is all you need to do.

Answer 2

Separating Identity:

Separating Identity from the UI is much trickier. Here, Microsoft has entangled them so closely that I would recommend leaving it until you understand Identity, EF, and the Repository Pattern at an expert level.

But, in case you are interested in separating Identity from the UI Level, here is a great resource from Dino Esposito

---

• Notice the reference to ApplicationDbContext in your Account Controller's Constructor:

  public AccountController()
      : this(new UserManager<ApplicationUser>(new UserStore<ApplicationUser>
                           (new ApplicationDbContext())))
  

This can easily be a reference to a Context in your DAL.

• you will have great difficulty using a Repo over a context. That would require re-writing the UserManager which I highly doubt you want to do.

• You can create a child that inherits from ApplicationDbContext and is abstracted with an Interface

:

public class UserIdentityContext : ApplicationDbContext, IUserIdentityContext 

Now you can use Ninject to bind your Account Controller to an Abstract Pattern

public AccountController()
    : this(new UserManager<ApplicationUser>(new UserStore<ApplicationUser>
                         (IUserIdentityContext identityContext)))

But none of these moves allow you to remove EF assemblies from your UI Project. Here Microsoft bound the Data and UI elements too closely. You would have to re-write the Account Controller.

It's an issue they are dealing with and will probably improve on greatly in a MVC 6 / Identity 3

Answer 3

It is possible and not that difficult to remove the ApplicationDbContext from your ui project. The most complete way is to create a webapi project that will expose the functions of the IUserStore, or at least just the functions you need, and you won't need them all. The web api methods just delegate to the underlying entityframework, used in a DAL or not. Like (with a repository)

  [HttpGet]
  [Route("finduserbyid/{userId}")]
  public async Task<IHttpActionResult> FindByIdAsync(string userId)
  {
     var verifiedUser = await this.UnitOfWork.ApplicationUserRepository.FindByIdAsync(userId);

     if (verifiedUser == null)
     {
        return NotFound();
     }

     return Ok(verifiedUser);
  }

Then create a new class in your ui project, or a utility project that implments IUserStore and calles the webapi for the data. I was able to do this in a day or so, not very difficult. Like this:

public class RemoteUserStore<T> : IUserStore<ApplicationUser>
    , IUserPasswordStore<ApplicationUser>
    , IUserLoginStore<ApplicationUser>
    , IUserRoleStore<ApplicationUser>
    , IUserEmailStore<ApplicationUser>
{
    public RemoteUserStore(string identityServerUrl)
    {
        _appServerUrl = identityServerUrl;
    }

    private readonly string _appServerUrl;
    private string IdentityServerUrl
    {
        get
        {
            return _appServerUrl;
        }
    }


    public async Task CreateAsync(ApplicationUser user)
    {
        var client = new HttpClient();
        string url = string.Format("{0}/api/identity/createuser/{1}", IdentityServerUrl, user.Id);

        var userContent = MapApplicationUserToFormContent(user);
        var result = await client.PostAsync(url, userContent);
    }

   //snip
}

You will not be able to eliminate a reference to entity framework however, as the UI will actually use the ApplicationUser with IdentityUser as a base class and it is defined in the microsoft.aspnet.identity.entityframework package