.net - SignalR长轮询5秒断线

Question

我的应用程序在公司网络下工作(丑陋的代理和东西)。它不能很好地工作。我希望使用 https 会有所帮助，但没有。这是我在日志中看到的一个奇怪的模式:

[14:13:32 GMT+0600 (N. Central Asia Standard Time)] SignalR: Client subscribed to hub 'modemshub'.
[14:13:32 GMT+0600 (N. Central Asia Standard Time)] SignalR: Negotiating with '/signalr/negotiate?clientProtocol=1.5&connectionToken=6aktO0sramoQKhQ9DC7Cs7EbXMUou8LooQRxfup4R0oZCHpBmWBFjyLup%2F3wJLloR8GtJEiUk10YOZJBaSqN8aiGAfXRR4G9hujTFTyiJiz%2FyJ4oMlBIdxqeCc5anI6k&connectionData=%5B%7B%22name%22%3A%22modemshub%22%7D%5D'.
[14:13:32 GMT+0600 (N. Central Asia Standard Time)] SignalR: longPolling transport starting.
[14:13:32 GMT+0600 (N. Central Asia Standard Time)] SignalR: Opening long polling request to 'https://example.com/signalr/connect?transport=longPolling&clientProt…rlCzGHl5kVLClT5ex8&connectionData=%5B%7B%22name%22%3A%22modemshub%22%7D%5D'.
[14:13:33 GMT+0600 (N. Central Asia Standard Time)] SignalR: Long poll complete.
[14:13:33 GMT+0600 (N. Central Asia Standard Time)] SignalR: LongPolling connected.
[14:13:33 GMT+0600 (N. Central Asia Standard Time)] SignalR: longPolling transport connected. Initiating start request.
[14:13:33 GMT+0600 (N. Central Asia Standard Time)] SignalR: Opening long polling request to 'https://example.com/signalr/poll?transport=longPolling&clientProtoco…rlCzGHl5kVLClT5ex8&connectionData=%5B%7B%22name%22%3A%22modemshub%22%7D%5D'.
[14:13:33 GMT+0600 (N. Central Asia Standard Time)] SignalR: The start request succeeded. Transitioning to the connected state.
[14:13:38 GMT+0600 (N. Central Asia Standard Time)] SignalR: Long poll complete.
[14:13:38 GMT+0600 (N. Central Asia Standard Time)] SignalR: Stopping connection.
[14:13:38 GMT+0600 (N. Central Asia Standard Time)] SignalR: Fired ajax abort async = true.

因此连接建立并在 5 秒后中止(而 ConnectionTimeout 等于 110 秒)。并且这种模式一次又一次地重复。那太奇怪了。

Answer 1

背景

根据 Asp.net :

SignalR uses the transport API to create a transport connection, and the transport API depends on the existence of a physical network connection to create the transport connection. The transport connection ends when SignalR terminates it or when the transport API detects that the physical connection is broken.

Physical connections might be slow or there might be interruptions in connectivity. Depending on factors such as the length of the interruption, the transport connection might be dropped. SignalR then tries to re-establish the transport connection. Sometimes the transport connection API detects the interruption and drops the transport connection, and SignalR finds out immediately that the connection is lost. In other scenarios, neither the transport connection API nor SignalR becomes aware immediately that connectivity has been lost. For all transports except long polling, the SignalR client uses a function called keepalive to check for loss of connectivity that the transport API is unable to detect.

Troubleshooting

请注意 SignalR 2.1 为长轮询引入了保活。如果某些东西干扰了分块的 HTTP 响应，这可能会出现问题。如果您想 disable keepalive功能，设置 KeepAlive至 null . Keepalive功能是自动的 disabled对于长轮询传输。

如果您是 using a Self-Host , 使用以下 带 3 个参数 反而:

GlobalHost.Configuration.ConnectionTimeout = new TimeSpan(0,0,110);
GlobalHost.Configuration.DisconnectTimeout = new TimeSpan(0,0,30);
GlobalHost.Configuration.KeepAlive = new TimeSpan(0,0,10);

作为支持长轮询保持事件“喜欢”功能的不同替代方案，创建一个服务器方法，将其命名为 Ping :

public class MyHub : Hub
{
    public void Ping()
    {
    }
}

然后，在客户端上创建一个区间，您将在该区间内 Ping服务器:

var proxy = $.connection.myHub,
    intervalHandle;  
...
$.connection.hub.disconnected(function() {
    clearInterval(intervalHandle);
});  
...  
$.connection.hub.start().done(function() {
    // Only when long polling
    if($.connection.hub.transport.name === "longPolling") {
        // Ping every 10s
        intervalHandle = setInterval(function() {
            // Ensure we're connected (don't want to be pinging in any other state).
            if($.connection.hub.state === $.signalR.connectionState.connected) {
                proxy.server.ping().fail(function() {
                    // Failed to ping the server, we could either try one more time to ensure we can't reach the server
                    // or we could fail right here.
                    TryAndRestartConnection(); // Your method
                });
            }
        }, 10000); 
    }
});

我希望有用。