Injecting IHttpContextAccessor into ApplicationDbContext ASP.NET Core 1.0

Question

I am trying to figure out how to get access to the current logged in username outside of an ASP.NET Controller.

For example I am trying to do this:

Track Created and Modified fields Automatically with Entity Framework Code First

To setup tracking on entities in the DbContext.

Here is my ApplicationDbContext but I keep getting an error saying _httpContextAccessor is null:

private readonly IHttpContextAccessor _httpContextAccessor;

public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options, IHttpContextAccessor httpContextAccessor)
    : base(options)
{
    _httpContextAccessor = httpContextAccessor;
}

See https://learn.microsoft.com/en-us/aspnet/core/fundamentals/http-context there is a `AddHttpContextAccessor` extension method. — Fred, Nov 21 '19 at 14:27

Nkosi · Accepted Answer · 2019-09-20T19:01:21.153

13

Try injecting the IHttpContextAccessor Interface

You can even abstract it further by creating a service to provide just the information you want (Which is the current logged in username)

public interface IUserResolverService {
    string GetUser();
}

public class UserResolverService : IUserResolverService {
    private readonly IHttpContextAccessor accessor;
    public UserResolverService(IHttpContextAccessor accessor) {
        this.accessor = accessor;
    }

    public string GetUser() {
        var username = accessor?.HttpContext?.User?.Identity?.Name ;
        return username ?? "unknown";
    }
}

You need to setup IHttpContextAccessor now in Startup.ConfigureServices in order to be able to inject it:

services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
//OR
//services.AddHttpContextAccessor();
services.AddTransient<IUserResolverService, UserResolverService>();

and pass that to your repository as needed to record associated username

edited Sep 20 '19 at 19:01

answered Aug 24 '16 at 19:53

Nkosi

235,767
35
427
472

I just saw a post on this actually. Should I just inject it into my ApplicationDbContext and create a private property? – Blake Rivell Aug 24 '16 at 19:54
More or less. yes – Nkosi Aug 24 '16 at 19:55
Alright, I am going to give it a go hoping that it is automatically injected. – Blake Rivell Aug 24 '16 at 19:57
And one from the same site to linked to in your post http://benjii.me/2015/07/using-sessions-and-httpcontext-in-aspnet5-and-mvc6/ – Nkosi Aug 24 '16 at 20:00
Hmm look at my updated post. I keep getting _httpContextAccessor is null – Blake Rivell Aug 24 '16 at 20:02
Update article says the same thing should work http://benjii.me/2016/07/using-sessions-and-httpcontext-in-aspnetcore-and-mvc-core/ – Nkosi Aug 24 '16 at 20:04
Do you really think I need to install Session just so HttpContextAccessor can be injected into my controller? – Blake Rivell Aug 24 '16 at 20:07
No. I'm just showing that for an example as it also shows how to use `IHttpContextAccessor` – Nkosi Aug 24 '16 at 20:08
@BlakeRivell, Apparently it is not setup automatically. You have to add it to the services collection in order to be able to inject it. – Nkosi Aug 24 '16 at 20:17
I added it and still getting the same null error. I used services.AddScoped – Blake Rivell Aug 24 '16 at 20:34
hmm i don't have an IUserResolverService. Resharper or Intellisense isnt showing an reocmmendations. – Blake Rivell Aug 24 '16 at 21:09
1

No. that is a custom interface you can create yourself to abstract the direct calls to the http context accessor. – Nkosi Aug 24 '16 at 21:30

score 6 · Answer 2 · answered Sep 29 '16 at 22:04

6

@Nkosi has the correct answer but please note that IHttpContextAccessor is now under the namespace:

Microsoft.AspNetCore.Http;

And no longer under:

Microsoft.AspNet.Http;

answered Sep 29 '16 at 22:04

Stephen Brickner

2,584
1
11
19

Injecting IHttpContextAccessor into ApplicationDbContext ASP.NET Core 1.0

2 Answers2

Linked