SignalR Core 如何获取服务器端的连接参数

Question

按照这个答案How to send Parameter/Query in HubConnection SignalR Core

我正在设置客户端：

const connectionHub = new HubConnectionBuilder()
.withUrl(Constants.URL_WEB_SOCKET + '?token=123')
.build();

但是服务器端如何获取token值呢？

public override async Task OnConnectedAsync()
{
    _connectionId = Context.ConnectionId;

    var token = Context.Items["token"]; // this is null

    var token2 = Context.QueryString["token"]; // 'HubCallerContext' does not contain a definition for 'QueryString' 

    await base.OnConnectedAsync();
 }

Answer 1

如果要在.net core中获取token值，可以使用如下代码：

var httpContext = Context.GetHttpContext();
var tokenValue = httpContext.Request.Query["token"];

Answer 2

您可以在 QueryString 中发送参数。

在您的客户端中，声明一个字符串字典和连接

private Dictionary<string, string> _querystringdata = new Dictionary<string, string>();
private HubConnection _connection;
private const string HubUrl = "your hub url";

然后，分配您要发送的值

 _querystringdata.Add("key", "Value");
 _connection = new HubConnection(HubUrl, _querystringdata);

开始连接

if (_connection.State == ConnectionState.Disconnected)
        {

            // Creating the signalrHub proxy
            IHubProxy signalrHub = _connection.CreateHubProxy("SignalrHub");
            Console.WriteLine("Initiating Connection");
            // starting the signalr connection
            _connection.Start().ContinueWith(task =>
            {
                if (task.IsFaulted)
                {
                    Console.WriteLine("There was an error opening the connection:{0}", task.Exception.GetBaseException());

                }
                else
                {
                    Console.WriteLine("Connected to server");

                    //Client methods which server can invoke
                    signalrHub.On<dynamic>("sendMessage", (data) =>
                    {
                        Console.WriteLine("Message:- {0}", data);
                        // do something
                    });
                }
            }).Wait(); 
        }

然后在您的服务器 signalR 集线器类中

 public override Task OnConnected()
    {
        try
        {
            // getting the value sent with query string
            var token = Context.QueryString.Get("Key");
            // do something like connection mapping etc
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return (base.OnConnected());
    }