I am using SignalR to transfer data on a website. But SignalR should only be able to send data for a period of time and if the time period has passed the connection should be killed.
The Stop-Function $.connection.hub.stop() is cancelled if a request is still pending and is not completed. But this request should be forced to cancel no matter how much data has been sent.
How can I kill a SignalR-Connection?
As you can see in this Microsoft Documentation about Timeout and keepalive settings you can define the DisconnectTimeout in the options.
Example:
protected void Application_Start(object sender, EventArgs e)
{
// Make long-polling connections wait a maximum of 110 seconds for a
// response. When that time expires, trigger a timeout command and
// make the client reconnect.
GlobalHost.Configuration.ConnectionTimeout = TimeSpan.FromSeconds(110);
// Wait a maximum of 30 seconds after a transport connection is lost
// before raising the Disconnected event to terminate the SignalR connection.
GlobalHost.Configuration.DisconnectTimeout = TimeSpan.FromSeconds(30);
// For transports other than long polling, send a keepalive packet every
// 10 seconds.
// This value must be no more than 1/3 of the DisconnectTimeout value.
GlobalHost.Configuration.KeepAlive = TimeSpan.FromSeconds(10);
RouteTable.Routes.MapHubs();
}
Edit: Since you want to kill the connection from the client no matter what, you are talking about a CancellationToken behavior but unfortunately this is still not supported in SignalR as you can see here and here, the team wants to do that to SignalR but still there is no news about it.
Please read this microsoft document about Hub lifetime event. You can change the default values for these settings, set them in Application_Start in your Global.asax file. But this way you can't full control client side. So you use javascript setTimeout function and pass the time form server end when a new user connect.it's may be GlobalHost.Configuration.DisconnectTimeout or any time you want. I give a full example with demo project. Actually i use this logic in a very large ticketing system for real-time holding ticket.(please read all inline comment)
Model:
public class MyModel
{
public int Id { get; set; }
public string Name { get; set; }
public static string Send(MyModel my)
{
//Do Somthing
return $"Data Sending to {my.Name}...";
}
public static string Stop(string name)
{
//Do Somthing
return $"ForceStop {name}.";
}
public static string Delete()
{
//Do Somthing
return "Deleted";
}
}
Hub:
[HubName("myHub")]
public class MyHub : Hub
{
int connectionTimeOut = 10;//sec
[HubMethodName("connect")]
public void Connect()
{
//apply logic if any when user connected or reload page
//set connection Time Out as you need
connectionTimeOut= 10;// GlobalHost.Configuration.DisconnectTimeout
Clients.Client(Context.ConnectionId).onNewUserConnected(connectionTimeOut);
}
[HubMethodName("startSendingServer")]
public void StartSending(int id, string name)//pass anything you need
{
//apply logic if any when start sending data
var my = new MyModel
{
Id = id,
Name = name
};
var status = MyModel.Send(my);//example
var result = new
{
status,
name
};
Clients.Client(Context.ConnectionId).startSendingClient(result);
}
[HubMethodName("forceStopServer")]
public void ForceStop(string name)//pass anything you need
{
//apply logic if any when force stop sending data
var status = MyModel.Stop(name);
Clients.Client(Context.ConnectionId).forceStopClint(status);
}
public override Task OnDisconnected(bool stopCalled)
{
//apply logic if any when connection Disconnected
var status = MyModel.Delete();//example
if (stopCalled)
{
// status=String.Format("Client {0} explicitly closed the connection.", Context.ConnectionId)
//your code here
}
else
{
// status=String.Format("Client {0} timed out .", Context.ConnectionId);
//your code here
//Clients.Client(Context.ConnectionId).onUserDisconnected(status);
}
return base.OnDisconnected(stopCalled);
}
}
TestView:
<div class="row">
<div class="col-md-12">
<h1> Status: <span id="hubStatus"></span></h1>
<br />
<h4> Countdown : <span id="counter"></span></h4>
<br />
<button id="btnHub" class="btn btn-primary btn-lg">Start Sending Data</button>
</div>
</div>
#section scripts{
<script src="~/Scripts/app/hub.js"></script>
}
hub.js:
var proxyTimer = null;
var sendTimeLimit = 1;//sec
var sessionTime = sendTimeLimit * 1000;
$(function () {
var myProxy = $.connection.myHub;
$.connection.hub.start().done(function () {
registerServerEvents(myProxy);
});
clientMethods(myProxy);
});
function registerServerEvents(proxyHub) {
proxyHub.server.connect();
$(document).on("click", "#btnHub", function (e) {
$("#hubStatus").html("Sending..");
$("#btnHub").text("Count Down Start...");
//Logic Before start sending data.
var id = 1;
var name = "AzR";
proxyHub.server.startSendingServer(id,name);
// $.connection.hub.disconnected(function () {
// setTimeout(function () { $.connection.hub.start(); }, 5000); // Restart connection after 5 seconds.
//});
$.connection.hub.disconnected(function () {
$("#hubStatus").html("Disconnected");// you can restart on here.
$("#btnHub").text("Stat Again after reload window");
});
});
}
function clientMethods(proxyHub) {
//proxyHub.on('onConnected', function (sendTimeLimit) {
// sendTimeLimit = sendTimeLimit;
//});
proxyHub.on('onNewUserConnected', function (serverItem) {
sendTimeLimit = serverItem;
sessionTime = sendTimeLimit * 1000;
});
proxyHub.on('startSendingClient', function (serverItem) {
//Logic after start sending data.
var name = serverItem.name;
var status = serverItem.status;
$("#hubStatus").html(status);
$("#counter").html(sendTimeLimit);
timeCounter();
startTimer(proxyHub, name );
});
proxyHub.on('forceStopClint', function (serverItem) {
clearClintPendingTask(serverItem);//Logic before proxy stop.
$("#btnHub").text("Force Stop...");
$.connection.hub.stop();
});
proxyHub.on('onUserDisconnected', function (serverItem) {
//Logic after proxy Disconnected (time out).
$("#hubStatus").html(serverItem);
$("#btnHub").text("Stat Again after reload window");
});
}
//Logic before proxy stop.
function clearClintPendingTask(status) {
//do all you need
$("#hubStatus").html(status);
stopTimer();
}
function startTimer(proxyHub,data) {
stopTimer();
proxyTimer = setTimeout(function () {
proxyHub.server.forceStopServer(data);
}, sessionTime);
}
function stopTimer() {
if (proxyTimer) {
clearTimeout(proxyTimer);
proxyTimer = null;
}
}
function timeCounter() {
var counter = sendTimeLimit;
var interval = setInterval(function () {
counter--;
$("#counter").html(counter);
if (counter == 0) {
//Do something
$("#counter").html("Countdown ended!");
// Stop the counter
clearInterval(interval);
}
}, 1000);
}
(Tested)
You need to define a timeout. On the server you can set DisconnectTimeout, like this:
GlobalHost.Configuration.DisconnectTimeout = TimeSpan.FromMinutes(30);
https://zzz.buzz/2016/05/11/setting-timeout-for-signalr-for-easier-debugging/
Updated Edit, please see Option 3 below. All the others are relying on timeout, I posted a forced disconnect.
If you are trying a Force Disconnect -- you can get the list of the Connected Users and call the ForceLogOut Function on the server side, I saw this somewhere on code project, I hope it helps. If you only want to forceLogout/kill some of the users, just loop through and kill that connection only.
Server Side
public class User
{
public string Name { get; set; }
public HashSet<string> ConnectionIds { get; set; }
}
public class ExtendedHub : Hub
{
private static readonly ConcurrentDictionary<string, User> ActiveUsers =
new ConcurrentDictionary<string, User>(StringComparer.InvariantCultureIgnoreCase);
public IEnumerable<string> GetConnectedUsers()
{
return ActiveUsers.Where(x => {
lock (x.Value.ConnectionIds)
{
return !x.Value.ConnectionIds.Contains
(Context.ConnectionId, StringComparer.InvariantCultureIgnoreCase);
}
}).Select(x => x.Key);
}
public void forceLogOut(string to)
{
User receiver;
if (ActiveUsers.TryGetValue(to, out receiver))
{
IEnumerable<string> allReceivers;
lock (receiver.ConnectionIds)
{
allReceivers = receiver.ConnectionIds.Concat(receiver.ConnectionIds);
}
foreach (var cid in allReceivers)
{
// ***************** log out/KILL connection for whom ever your want here
Clients.Client(cid).Signout();
}
}
}
}
Client Side
// 1- Save your connection variable when you start it, and later on you can use it to stop.
var myHubProxy = $.connection.myHub
// 2- Use it when you need to stop it, IF NOT YOU WILL GET AN ERROR
myHubProxy.client.stopClient = function() {
$.connection.hub.stop();
};
// With a button for testing
$('#SomeButtonKillSignalr').click(function () {
$.connection.hub.stop();
});
Updated with Option 3: based on request... the other solutions rely on time out, but you can also force it directly by disposing the connection yourself
I opened the SignalR code up, and inside you can see DisposeAndRemoveAsync the actual termination of a client connection.
1- You can modify or call DisposeAndRemoveAsync with your connection.
2- Then call RemoveConnection(connection.ConnectionId);
public async Task DisposeAndRemoveAsync(HttpConnectionContext connection)
{
try
{
// this will force it
await connection.DisposeAsync();
}
catch (IOException ex)
{
_logger.ConnectionReset(connection.ConnectionId, ex);
}
catch (WebSocketException ex) when (ex.InnerException is IOException)
{
_logger.ConnectionReset(connection.ConnectionId, ex);
}
catch (Exception ex)
{
_logger.FailedDispose(connection.ConnectionId, ex);
}
finally
{
// Remove it from the list after disposal so that's it's easy to see
// connections that might be in a hung state via the connections list
RemoveConnection(connection.ConnectionId);
}
}
Caution, do any clean up yourself when this is done.
Related
(I'm new to Signalr)
I'm developing an web application which uses Signalr-core to update the page in realtime.
The problem i walk into is that when i run multiple clients the method i'm running wil run as many times at once as there are clients.
so i want to know if there is any way to make the first client call the hub method and then keep it running and broadcasting to all connected clients.
this is what i'm doing with my client:
connection.on('update', (id, Color) => {
var x = document.getElementById(id);
if (Color === "green" && x.classList.contains("red"))
{
//console.log("green");
x.classList.remove("red");
x.classList.add("green");
}
else if (Color === "red" && x.classList.contains("green"))
{
//console.log("Red");
x.classList.remove("green");
x.classList.add("red");
}});
connection.start()
.then(() => connection.invoke('updateclient', updating));
and this is what i'm doing with my hub:
public void UpdateClient(bool updating)//this must run only once
{
while (updating == true)
{
Thread.Sleep(2000);
foreach (var item in _context.Devices)
{
IPHostEntry hostEntry = Dns.GetHostEntry(item.DeviceName);
IPAddress[] ips = hostEntry.AddressList;
foreach (IPAddress Ip in ips)
{
Ping MyPing = new Ping();
PingReply reply = MyPing.Send(Ip, 500);
if (reply.Status == IPStatus.Success)
{
Color = "green";
Clients.All.InvokeAsync("update", item.DeviceID, Color);
break;
}
else
{
Color = "red";
Clients.All.InvokeAsync("update", item.DeviceID, Color);
}
}
}
}
}
please let me know if i'm unclear about something.
and thank you in advance.
As I mention in the comment, you can invoke UpdateClient method on first appearance of any client. The option I came up with is as follows;
It is quite common to use a static list for clients connected to hub
public static class UserHandler
{
public static List<string> UserList = new List<string>();
}
In your hub, override OnConnected and OnDisconnected methods to add/remove clients to/from the list and define the very first client connected to hub for your purpose.
public class MyHub : Hub
{
private static IHubContext context = GlobalHost.ConnectionManager.GetHubContext<MyHub>();
public override Task OnConnected()
{
//Here check the list if this is going to be our first client and if so call your method, next time because our list is filled your method won't be invoked.
if(UserHandler.UserList.Count==0)
UpdateClient(true);
UserHandler.UserList.Add(Context.ConnectionId)
return base.OnConnected();
}
public override Task OnDisconnected(bool stopCalled)
{
UserHandler.UserList.RemoveAll(u => u.ConnectionId == Context.ConnectionId);
return base.OnDisconnected(stopCalled);
}
}
I didn't take your business logic or your needings into consideration, this is just a general idea. For example, you might want to add some logic for when all the clients goes off, you should stop the loop inside UpdateClient with using updating flag.
Hub-code
public class TestHub : Hub
{
public void Message(string message)
{
Clients.Group("testGroup").displayMessage(message);
}
public override Task OnConnected()
{
Groups.Add(Context.ConnectionId, "testGroup");
return base.OnConnected();
}
}
Javascript Code with generated Proxy
var myHub = $.connection.testHub;
myHub.on('message', this.displayMessage);
$.connection.hub.start();
function displayMessage(message) {
console.log(message);
}
If I do the above it seems like the hub.start() is running correctly and it returns some form of object. But when i debug with a breakpoint inside OnConnected I never hit.
Any suggestions?
Basiclly, you can invoke hub methods but the OnConnect won't work if you don't have subscriptions on the hub.
It's weird but that's the way it works.
Do it like this:
var myHub = $.connection.testHub;
//add subscriptions
$.extend(myHub.client, {
stupidLogicSignalR: function () {}
});
myHub.on('message', this.displayMessage);
$.connection.hub.start();
Here's a similar question.
Also this issue can help
Worked with other syntax for the subscribe
myHub.client.displayMessage = () => {console.log('message');};
enable logging at front end by(do it after var myHub = $.connection.testHub;):
$.connection.hub.logging = true;
or assign a callback to .start by:
$.connection.hub.start().done(function () {
console.log("connection started")
});
I am new to SignalR. I need to send message from SignalR to all connected clients automatically with some delay without client input ?
The above process has to be repeated, while recursively?
Is it possible?
Without client input, the SignalR can send messages automatically to clients repeatedly?
This is my JavaScript cleint code:
$(function () {
var chat = $.connection.timehub;
$.connection.hub.start();
chat.client.broadcastMessage = function (current) {
var now = current;
console.log(current);
$('div.container').append('<p><strong>' + now + '</strong></p>');
}
};
and this is my Timehub
public class timehub : Hub
{
public void Send(string current)
{
current = DateTime.Now.ToString("HH:mm:ss:tt");
Clients.All.broadcastMessage(current);
System.Threading.Thread.Sleep(5000);
Send(current);
}
}
and this is my Owin Startup Class:
public class Startup
{
public void Configuration(IAppBuilder app)
{
app.MapSignalR();
}
}
Could anyone provide me an solution for this?
If you will keep calling the Send() method recursively like you do right now, you will get a stackoverflow exception. Just wrap the code inside the method in a while(true) loop:
public class timehub : Hub
{
public void Send()
{
while(true)
{
var current = DateTime.Now.ToString("HH:mm:ss:tt");
Clients.All.broadcastMessage(current);
System.Threading.Thread.Sleep(5000);
}
}
}
I would suggest moving the Send() method to another thread, because the current thread will get stuck forever in this while loop.
I am trying to implement CometD in our application. But it is taking more time compared to the existing implementation in our project. The existing system is taking time in milliseconds where as CometD is taking 2 seconds to push the message.
I am not sure where I am going wrong. Any guidance will help me lot.
My code:
Java script at client side
(function($)
{
var cometd = $.cometd;
$(document).ready(function()
{
function _connectionEstablished()
{
$('#body').append('<div>CometD Connection Established</div>');
}
function _connectionBroken()
{
$('#body').append('<div>CometD Connection Broken</div>');
}
function _connectionClosed()
{
$('#body').append('<div>CometD Connection Closed</div>');
}
// Function that manages the connection status with the Bayeux server
var _connected = false;
function _metaConnect(message)
{
if (cometd.isDisconnected())
{
_connected = false;
_connectionClosed();
return;
}
var wasConnected = _connected;
_connected = message.successful === true;
if (!wasConnected && _connected)
{
_connectionEstablished();
}
else if (wasConnected && !_connected)
{
_connectionBroken();
}
}
// Function invoked when first contacting the server and
// when the server has lost the state of this client
function _metaHandshake(handshake)
{
if (handshake.successful === true)
{
cometd.batch(function()
{
cometd.subscribe('/java/test', function(message)
{
$('#body').append('<div>Server Says: ' + message.data.eventID + ':'+ message.data.updatedDate + '</div>');
});
});
}
}
// Disconnect when the page unloads
$(window).unload(function()
{
cometd.disconnect(true);
});
var cometURL = "http://localhost:8080/cometd2/cometd";
cometd.configure({
url: cometURL,
logLevel: 'debug'
});
cometd.addListener('/meta/handshake', _metaHandshake);
cometd.addListener('/meta/connect', _metaConnect);
cometd.handshake();
});
})(jQuery);
Comet service class
#Listener("/service/java/*")
public void processMsgFromJava(ServerSession remote, ServerMessage.Mutable message)
{
Map<String, Object> input = message.getDataAsMap();
String eventId = (String)input.get("eventID");
//setting msg id
String channelName = "/java/test";
// Initialize the channel, making it persistent and lazy
bayeux.createIfAbsent(channelName, new ConfigurableServerChannel.Initializer()
{
public void configureChannel(ConfigurableServerChannel channel)
{
channel.setPersistent(true);
channel.setLazy(true);
}
});
// Publish to all subscribers
ServerChannel channel = bayeux.getChannel(channelName);
channel.publish(serverSession, input, null);
}
Is there any thing I need to change in server side code.
You have made your channel lazy, so a delay in message broadcasting is expected (that is what lazy channels are all about).
Please have a look at the documentation for lazy channels.
If you want immediate broadcasting don't set the channel as lazy.
I have searched for several days now, and have tried about every solution that I could find. I know this is something I am not doing correctly, however, I am not sure what the correct way is.
I have an ASP.Net C# web site, running on .Net Framework 4.5. I have a link button on a form, that when clicked fires off a long running process using the ThreadPool. I have a delegate callback setup, and the code does fire when the process is canceled or when it finishes. (I am using the Cancelation Token for canceling the process and the process is Active Reports in case that matters.)
Like I said, everything works great, except for when the callback code fires it does not execute the javascript. (FYI -- this is NOT a javascript callback, just trying to fire off some javascript code when the process finishes.)
Here is the code that i start the report...
string sThreadID = Thread.CurrentThread.ManagedThreadId.ToString();
ThreadPool.QueueUserWorkItem(new WaitCallback(StartReport), cts.Token);
Here is the code for the StartReport....
public static void StartReport(object obj) {
try {
OnTaskCompleteDelegate callback = new OnTaskCompleteDelegate(OnTaskComplete);
BoyceReporting.CallReport(boyce.BoyceThreadingEnvironment.OBRO, "THREADING");
if (boyce.BoyceThreadingEnvironment.CTS.Token.IsCancellationRequested) {
boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute = "alert('Report Canceled By User');";
callback("CANCELED");
} else {
callback("FINISHED");
}
} catch {
throw;
}
}
Here is the code for the CallBack code.....
public static void OnTaskComplete(string ReportResult) {
try {
sReportResult = ReportResult;
if (ReportResult == "CANCELED") {
// In case we need to do additional things if the report is canceled
}
string sThreadID = Thread.CurrentThread.ManagedThreadId.ToString();
boyce.BoyceThreadingEnvironment.THISPAGE.ClientScript.RegisterStartupScript(boyce.BoyceThreadingEnvironment.THISPAGE.GetType(), "FireTheScript" + DateTime.Now.ToString(), boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute, true);
ScriptManager.RegisterStartupScript(boyce.BoyceThreadingEnvironment.THISPAGE, boyce.BoyceThreadingEnvironment.THISPAGE.GetType(), "DisplayReport" + DateTime.Now.ToString(), boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute, true);
} catch {
throw;
}
}
Here is the issue that I am having.....
Everything works fine except i can not get the last line of code to fire the script.
ScriptManager.RegisterStartupScript
Here is what I think is happening.....
From looking at the thread ID, I am sure the reason that the code is not firing is because the ScriptManager code that I am trying to fire in the Call Back event is on a different thread, other than the main thread.
Here is my question(s).....
(1) Am I correct in why this is not firing the JavaScript
(2) How can I (from inside of the CallBack) get this JavaScript to fire? Is there a way to force this to execute on the main Thread?
It's not firing in JS because you're spinning off a new thread. In the meantime, the request has long since returned to the client and closed the connection. By the time the thread tries to write something out to the Response, it's already finished.
Instead of doing it this way, just have your button click (or whatever it is that kicks off the report), inside of an UpdatePanel. Then, you don't need to fire off a new thread.
Here is the cod I used in the C# Code Behind to call the web service to start monitoring this process.
----------------------------------------------------------------------------------------------
CurrentSession.bIsReportRunning = true;
ScriptManager.RegisterStartupScript(this, this.GetType(), "WaitForReport" + DateTime.Now.ToString(), "jsWaitOnCallReport();", true);
MultiThreadReport.RunTheReport(HttpContext.Current, CurrentSession, this, oBRO);
Here is the code that calls the method, using the threadpool, and the method called..
----------------------------------------------------------------------------------------------
ThreadPool.QueueUserWorkItem(new WaitCallback(StartReport), cts.Token);
public static void StartReport(object obj) {
try {
OnTaskCompleteDelegate callback = new OnTaskCompleteDelegate(OnTaskComplete);
BoyceReporting.CallReport(boyce.BoyceThreadingEnvironment.OBRO, "THREADING");
HttpContext.Current = boyce.BoyceThreadingEnvironment.CONTEXT;
if (boyce.BoyceThreadingEnvironment.CTS.Token.IsCancellationRequested) {
boyce.BoyceThreadingEnvironment.SESSION.sScriptToExecute = "alert('Report Canceled By User');";
boyce.BoyceThreadingEnvironment.SESSION.bIsReportRunning = false;
callback("CANCELED");
} else {
boyce.BoyceThreadingEnvironment.SESSION.bIsReportRunning = false;
callback("FINISHED");
}
} catch {
throw;
}
}
Here is the web service method I created to monitor the process, with a built in safety net
--------------------------------------------------------------------------------------------
[WebMethod(EnableSession = true)]
public string WaitOnReport() {
try {
HttpContext.Current = boyce.BoyceThreadingEnvironment.CONTEXT;
SessionManager CurrentSession;
CurrentSession = (SessionManager)boyce.BoyceThreadingEnvironment.SESSION;
DateTime dtStartTime = DateTime.Now;
DateTime dtCurrentTime = DateTime.Now;
if (CurrentSession != null) {
do {
// Build a safety limit into this loop to avoid an infinate loope
// If this runs longer than 20 minutes, then force an error due to timeout
// This timeout should be lowered when they find out what the issue is with
// the "long running reports". For now, I set it to 20 minutes but shoud be MUCH lower.
dtCurrentTime = DateTime.Now;
TimeSpan span = dtCurrentTime-dtStartTime;
double totalMinutes = span.TotalMinutes;
if (totalMinutes>=20) {
return "alert('Error In Creating Report (Time-Out)');";
}
} while (CurrentSession.bIsReportRunning == true);
// If all goes well, return the script to either OPEN the report or display CANCEL message
return CurrentSession.sScriptToExecute;
} else {
return "alert('Error In Creating Report (Session)');";
}
} catch {
throw;
}
}
And here is the JavaScript code I used to initiate the Web Service Call and Also The Postback
--------------------------------------------------------------------------------------------
function jsWaitOnCallReport() {
try {
var oWebService = BoyceWebService.WaitOnReport(jsWaitOnCallReport_CallBack);
} catch (e) {
alert('Error In Calling Report Screen -- ' + e);
}
}
function jsWaitOnCallReport_CallBack(result) {
try {
eval(result);
var myExtender = $find('ModalPopupExtenderPROGRESS');
if (myExtender != null) {
try {
myExtender.hide();
} catch (e) {
// Ignore Any Error That May Be Thrown Here
}
}
$find('PROGRESS').hide();
} catch (e) {
alert('Error In Opening Report Screen -- ' + e);
}
}
Hope this helps someone else out.. Like I said, I am not sure this is the best solution, but it works.. I would be interested in other solutions for this issue to try... Thanks.