Authentication, email / password and knowing which bank is correct

Question

The idea is a Saas application.

Where there will be only 1 single deploy. and customers will be separated by bank

Once this is done, there will be a login screen, where login(email)/password is entered

But how do I forward it to the correct database ? how could this table/class structure be?

Answer 1

1: Make two contexts: one of users, the other of tables of the system

I think the idea is to have all the same contexts, with just the Connection String different. In this case, it is interesting to have a common context:

public class MeuContexto : DbContext 
{
    public MeuContexto(String connectionString) : base(connectionString) 
    { }
    // Coloque seus DbSets aqui
}

And another context that only stores user data:

public class UsersContext : DbContext 
{
    public MeuContexto() : base("DefaultConnection") 
    { }
    // Coloque seus DbSets de usuário aqui
}

In this user context, you can have a Model keep the Connection Strings.

2: Implement a ActionFilter which determine which Connection String will be used

public class CustomActionFilter : ActionFilterAttribute, IActionFilter
{
    void IActionFilter.OnActionExecuting(ActionExecutingContext filterContext)
    {
        var usersContext = new usersContext();

        var user = usersContext.Users.SingleOrDefault(u => u.Name == User.Identity.Name);

        filterContext.HttpContext.Items["connectionString"] = user.Company.ConnectionString;

        this.OnActionExecuting(filterContext);
    }
}

3. Recover the Connection String within your Action

In this case, you will have to start a context for each Action.

[CustomActionFilter]
public class MeuController : Controller
{
    public ActionResult Index()
    {
        using (var context = new MeuContexto(HttpContext.Items["connectionString"].ToString()))
        {
            // Use seu contexto aqui normalmente
        }
    }
}