如何访问 Blazor 服务器客户端的当前电路

Question

我正在开发一个使用 ASP.NET Core Identity 的 Blazor 服务器项目。我正在尝试实现一个组件来管理当前的活动用户。我可以访问当前客户端的当前身份用户，但我似乎无法访问与当前客户端关联的电路，因为我想跟踪每个用户何时离开浏览器（电路断开连接）。

从'@enet' (link) 的回答中，我尝试实现CircuitHandler，并且我可以获得所有当前电路，但我如何知道哪个电路与哪个用户相关联？

using Microsoft.AspNetCore.Components.Server.Circuits;
using System;
using System.Collections.Concurrent;
using System.Threading;
using System.Threading.Tasks;


namespace BlazorCircuitHandler.Services
{
    public class CircuitHandlerService : CircuitHandler
    {
        public ConcurrentDictionary<string, Circuit> Circuits { get; 
            set; }
        public event EventHandler CircuitsChanged;

        protected virtual void OnCircuitsChanged()
             => CircuitsChanged?.Invoke(this, EventArgs.Empty);

        public CircuitHandlerService()
        {
             Circuits = new ConcurrentDictionary<string, Circuit>();
        }

        public override Task OnCircuitOpenedAsync(Circuit circuit, 
                             CancellationToken cancellationToken)
       {
             Circuits[circuit.Id] = circuit;
             OnCircuitsChanged();
             return base.OnCircuitOpenedAsync(circuit, 
                                   cancellationToken);
       }

       public override Task OnCircuitClosedAsync(Circuit circuit, 
                 CancellationToken cancellationToken)
      {
           Circuit circuitRemoved;
           Circuits.TryRemove(circuit.Id, out circuitRemoved);
           OnCircuitsChanged();
           return base.OnCircuitClosedAsync(circuit, 
                             cancellationToken);
      }

      public override Task OnConnectionDownAsync(Circuit circuit, 
                            CancellationToken cancellationToken)
      {
          return base.OnConnectionDownAsync(circuit, 
                           cancellationToken);
      }

      public override Task OnConnectionUpAsync(Circuit circuit, 
                          CancellationToken cancellationToken)
      {
          return base.OnConnectionUpAsync(circuit, cancellationToken);
      }
   }
 }

Answer 1

如果您使用 AddHttpContextAccessor 服务

services.AddHttpContextAccessor();

您可以在创建电路时获取用户：

public class MyCircuitIdStashingHandler: CircuitHandler
{
    public override Task OnCircuitOpenedAsync(Circuit circuit, CancellationToken cancellationToken)
    {
        IHttpContextAccessor accessor = new HttpContextAccessor();
        accessor.HttpContext.User.Identity; // store in dictionary somewhere
        return base.OnCircuitOpenedAsync(circuit, cancellationToken);
    }
}

...然后您可以跟踪哪个用户正在使用哪个电路