将当前用户注入OWIN Self-Host Web API的服务

Question

我在OWIN Self-Host Web API中使用带有业务逻辑的服务，我想将当前用户注入此服务。

这是我的IdentityService with CurrentUser属性：

public class IdentityService : IIdentityService
{
    private readonly UserManager<User, int> userManager;

    public IdentityService(UserManager<User, int> userManager)
    {
        if (userManager == null)
        {
            throw new ArgumentNullException("userManager");
        }

        this.userManager = userManager;
    }

    public User CurrentUser
    {
        get
        {
            var identity = Thread.CurrentPrincipal;

            if (identity == null || identity.Identity == null || !identity.Identity.IsAuthenticated)
            {
                if (HttpContext.Current == null || HttpContext.Current.User == null)
                {
                    return null;
                }

                identity = HttpContext.Current.User;
            }

            var user = this.userManager.FindByName(identity.Identity.Name);
            return user;
        }
    }
}

对于自托管的Web API，HttpContext.Current为null，我应该检查一下吗？也许是确定当前用户的更好方法？