Using Dependency Injection in Custom Filter .net Core always null

Question

When I am using the DI in TokenAuthorizeFilter, the _User always return null.Not only the _User, this is only an example of what I am encountered. I've tried different ways but still doesn't work.

I'm confused now, please tell me why. Thank you

public class BaseAuthorizeFilter : IAuthorizationFilter, IActionFilter
{
    public static ClaimsIdentity _User;
    public static IHttpContextAccessor _accessor;

    public BaseAuthorizeFilter(UserResolverService userService, IHttpContextAccessor accessor)
    {
        _User = userService.GetUser();
        _accessor = accessor;
    }
}
...

UserResolverService.cs

public class UserResolverService : IUserResolverService
{
    private readonly IHttpContextAccessor _context;

    public UserResolverService(IHttpContextAccessor context)
    {
        _context = context;
    }

    public ClaimsIdentity GetUser()
    {
        return _context.HttpContext.User.Identity as ClaimsIdentity;
        //await
    }
}

public interface IUserResolverService
{
    ClaimsIdentity GetUser();
}

TokenAuthorizeFilter.cs

public class TokenAuthorizeFilter : BaseAuthorizeFilter
{
    var identity = _User;
}

Sorry, I didn’t mentioned something in my question. I am calling a method in TokenAuthorizeFilter from another class so I defined it as static. Now I change my way writing it, and I found the answer from Microsoft’s website. Thanks a lot.

https://learn.microsoft.com/en-us/aspnet/core/mvc/controllers/filters?view=aspnetcore-2.1#ifilterfactory-implemented-on-your-attribute

Where are you registering your filter? Is it just _User that's null, or also _accessor? — ProgrammingLlama
– ProgrammingLlama, Commented Oct 5, 2018 at 7:44
Also the _accessor in Startup.cs: services.AddSingleton<TokenAuthorizeFilter>(); Do you mean this? — 李韋德
– 李韋德, Commented Oct 5, 2018 at 7:45
Why are you registering it as a singleton? That's very likely to be your problem. — ProgrammingLlama
– ProgrammingLlama, Commented Oct 5, 2018 at 7:48
I think that's OK, but BaseAuthorizeFilter should not be a singleton. — ProgrammingLlama
– ProgrammingLlama, Commented Oct 5, 2018 at 7:52
You showed me this: services.AddSingleton<TokenAuthorizeFilter>();? — ProgrammingLlama
– ProgrammingLlama, Commented Oct 5, 2018 at 7:59

Edward · Accepted Answer · 2018-10-08 07:42:35Z

There are multiple issues in your post.

You register IUserResolverService by services.AddSingleton<IUserResolverService, UserResolverService>();, but you inject UserResolverService userService,
You should not define ClaimsIdentity _User as static, it should be request isolation

try to change like below:

    public class BaseAuthorizeFilter : IAuthorizationFilter, IActionFilter
{
    public ClaimsIdentity _User;
    public IHttpContextAccessor _accessor;

    public BaseAuthorizeFilter(IUserResolverService userService, IHttpContextAccessor accessor)
    {
        _User = userService.GetUser();
        _accessor = accessor;
    }

Check the difference between your TokenAuthorizeFilter and below code:

public class TokenAuthorizeFilter : BaseAuthorizeFilter
{
   public TokenAuthorizeFilter(IUserResolverService userService
       , IHttpContextAccessor accessor):base(userService, accessor)
  {
      var identity = _User;
  }
}

Register TokenAuthorizeFilter as AddScoped

    services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
    services.AddSingleton<IUserResolverService, UserResolverService>();
    services.AddScoped<TokenAuthorizeFilter>();

Collectives™ on Stack Overflow

Using Dependency Injection in Custom Filter .net Core always null

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related