Question

我正在与SignalR 2.0进行一些聊天应用程序（就像每个人一样）。

我有一个win8.1应用程序，当应用程序关闭时，集线器接收OnDisconnected事件并从集线器上的列表中删除用户。集线器向每个客户端发送用户已离开聊天的内容，因此我们可以看到用户已离开。

但是当我在网页中使用SignalR和Javascript并且页面关闭时，集线器不会收到关闭标签/浏览器的通知......

任何人都知道如何关闭连接？

我编码的内容：

启动中心

[assembly: OwinStartup(typeof(ChatServer.Startup))]

namespace ChatServer
{
public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        // Map all hubs to "/signalr"
        app.MapSignalR();
    }
}
}

集线器

[HubName("ChatHub")]
public class ChatHub : Hub
{
    private static List<User> Users = new List<User>();
    public void Send(string name, string message)
    {
        // Call the broadcastMessage method to update clients.
        Clients.All.broadcastMessage(name, message, DateTime.Now);
    }

    public void UserConnected(string name)
    {
        Clients.Caller.connected(JsonConvert.SerializeObject(Users));
        User user = new User() { Name = name, ConnectionID = Context.ConnectionId };
        Clients.Others.userConnected(JsonConvert.SerializeObject(user));
        Users.Add(user);
    }

    public void UserLeft()
    {
        if(Users.Any(x=>x.ConnectionID == Context.ConnectionId))
        {
            User user = Users.First(x => x.ConnectionID == Context.ConnectionId);
            Users.Remove(user);
            Clients.Others.userLeft(JsonConvert.SerializeObject(user), Context.ConnectionId);
        }
    }

    public override System.Threading.Tasks.Task OnDisconnected()
    {
        // Only called when win8.1 app closes
        // Not called when browsers closes page
        UserLeft();
        return base.OnDisconnected();
    }
}

HTML - Javascript：

使用Javascript：

chat = new function () {

var ChatHub;
// Connecting to the hub
this.attachEvents = function () {
    if ($.connection != null) {
        ChatHub = $.connection.ChatHub;
       $.connection.hub.start({ transport: 'auto' }, function () {
            // Register client on hub
            ChatHub.server.userConnected("web name");
        });
    }

    this.send = function (name,message) {
        if ($.connection != null) {
                //Send chat message
                ChatHub.server.send(name, message).fail(function (e) {
                    alert(e);
                });
        }
    }
  }
};

 window.onbeforeunload = function (e) {
    //This is called when we close the page
    $.connection.hub.stop();
    return "You killed me! :'(";
};

Win8.1客户端

    internal async void ConnectToHub(string userName)
    {
        try
        {
            HubConnection hubConnection = new HubConnection(SERVER_PROXY);
            chat = hubConnection.CreateHubProxy("ChatHub");
            Context = SynchronizationContext.Current;

            MakeHubFunctionsAvailableOnClient();

            await hubConnection.Start();
            // Register client on hub
            await chat.Invoke("UserConnected", userName);
        }
        catch (Exception)
        {
            throw;
        }
    }

    private void MakeHubFunctionsAvailableOnClient()
    {
        //Receive chat messages
        chat.On<string, string, DateTime>("broadcastMessage",
                (name, message, date) => Context.Post(
                    delegate {
                        Messages.Add(new UserMessage() { Message = message, User = name, Date = date }); 
                    }, null
                )
        );

        //Receive all online users
        chat.On<string>("connected",
                (users) => Context.Post(
                    delegate
                    {
                        List<User> userList = JsonConvert.DeserializeObject<List<User>>(users);
                        foreach (User user in userList)
                        {
                            Users.Add(user);
                        }
                        Messages.Add(new UserMessage() { Message = "CONNECTED", User = "System", Date = DateTime.Now }); 
                    }, null
                )
        );

        //New user connected
        chat.On<string>("userConnected",
                (user) => Context.Post(
                    delegate
                    {
                        User newUser = JsonConvert.DeserializeObject<User>(user);
                        Users.Add(newUser);
                        Messages.Add(new UserMessage() { Message = newUser.Name + " CONNECTED", User = "System", Date = DateTime.Now }); 
                    }, null
                )
        );

        //User left, remove user from list on client
        chat.On<string>("userLeft",
                (user) => Context.Post(
                    delegate
                    {
                        User newUser = JsonConvert.DeserializeObject<User>(user);
                        User y = Users.First(x=>x.ConnectionID == newUser.ConnectionID);
                        bool ux  = Users.Remove(y);
                        Messages.Add(new UserMessage() { Message = newUser.Name + " left the conversation", User = "System", Date = DateTime.Now });
                    }, null
                )
        );
    }

当我关闭标签/浏览器/导航到其他网站时，我的集线器不会触发OnDisconnected 该网站是一个单页网站（暂时）

我使用的浏览器是什么？
Chrome：版本32.0.1700.68 beta-m
Internet Explorer 11

Answer 1

我想您的问题是如何检测特定用户是否离开或关闭了浏览器。当用户进入或离开时，向其他用户发送通知。

我认为问题是你没有正确处理OnConnected和OnDisconnected。要使其工作，首先您需要知道连接到集线器的每个客户端都传递唯一的连接ID。您可以在集线器上下文的Context.ConnectionId属性中检索此值。当每个客户都进来时，他们会经过OnConnected，当他们离开时，他们会经过OnDisconnected。以下是一个工作示例：

集线器类

[HubName("ChatHub")]
    public class ChatHub : Hub
    {
        private static List<User> Users = new List<User>();
        public void Send(string message)
        {
            var name = Context.User.Identity.Name;
            Clients.All.broadcastMessage(name, message, DateTime.Now.ToShortDateString());
        }
        public override Task OnConnected()
        {
            User user = new User() { Name = Context.User.Identity.Name, ConnectionID = Context.ConnectionId };
            Users.Add(user);
            Clients.Others.userConnected(user.Name);
            return base.OnConnected();
        }
        public override Task OnDisconnected()
        {
            if (Users.Any(x => x.ConnectionID == Context.ConnectionId))
            {
                User user = Users.First(x => x.ConnectionID == Context.ConnectionId);
                Clients.Others.userLeft(user.Name);   
                Users.Remove(user);
            }
            return base.OnDisconnected();
        }
    }

查看

<input type="text" id="message" /> <button class="btn">Send</button> <ul id="contents"></ul> @section scripts { <script src="~/Scripts/jquery-1.10.2.js"></script> <script src="~/Scripts/jquery.signalR-2.0.1.js"></script> <script src="/signalr/hubs"></script> <script> var chatHub = $.connection.ChatHub; chatHub.client.broadcastMessage = function (name, message, time) { var encodedName = $('<div />').text(name).html(); var encodedMsg = $('<div />').text(message).html(); var encodedTime = $('<div />').text(time).html(); $('#contents').append('<li><strong>' + encodedName + '</strong>:  ' + encodedMsg + '</strong>:  ' + encodedTime + '</li>'); }; chatHub.client.userConnected = function (data) { $('#contents').append('<li>Wellcome<strong>' + '</strong>:' + data + '</li>'); }; chatHub.client.userLeft = function (data) { $('#contents').append('<li>Bye<strong>' + '</strong>:' + data + '</li>'); }; $(".btn").on("click", function() { chatHub.server.send($("#message").val()); }); $.connection.hub.start().done(function() { console.log("connected..."); }); </script> }

Answer 2

您可能遇到此处描述的问题：https://github.com/SignalR/SignalR/issues/2719

tl; dr：Chrome 31中引入了一个已在Chrome Canary中修复的错误，可防止SignalR立即触发OnDisconnected。

如果您是，您可以使用我在问题中建议的解决方法，即将以下内容添加到您的JS代码中。

window.onbeforeunload = function (e) {
    $.connection.hub.stop();
};

即使有这个错误并且没有解决方法，我希望SignalR在浏览器退出主持SignalR的页面后大约35s引发OnDisconnected。

您能否提供有关您遇到此问题的浏览器以及在何种情况下的更多详细信息？（例如，关闭选项卡，关闭窗口，刷新，导航到同一站点上的另一个页面，导航到其他站点等）。

何时使用来自浏览器的SignalR关闭连接

2 个答案: